September 18-21, 2012 University of Graz

62nd Annual Meeting Austrian Physical Society September 18-21, 2012 University of Graz

Karl-Franzens-Universit¨atGraz ReSoWi-Zentrum, Universit¨atsstrasse15 8010 Graz, Austria Impressum

Herausgeber Fürdie OPG:¨ Michael Ramsey Karl-Franzens-UniversitätGraz Institut fürPhysik Surface- and Interface Physics Universitätsplatz5 8010 Graz Austria

Tel: +43 316 380 5203 Fax: +43 316 380 9816 E-mail: [email protected] Layout M. Wagner, A. Windisch

Druck Karl-Franzens-Universit¨atGraz Danksagung / Acknowledgements

Die Organisatoren danken f¨urdie freundliche Unterst¨utzungvon:

The organizers wish to thank the support of:

Organisation Committee

Michael Ramsey Georg Koller Joachim Krenn Leopold Mathelitsch Reinhard Alkofer Falko Netzer

1 2 3 Programme of the 62nd Annual Meeting ÖPG 2012 Tuesday, 18th September Wednesday, 19th September Registration: 9:00 – 16:30 Registration: 08:30 – 16:30 9:00 – 10:00, HS 15.03 Plenary Talk John Swain (Boston) Cosmic Rays: An Ongoing Clear Window into New Physics 10:00 – 11:00, HS 15.03 Plenary Talk Franz Gießibl (Regensburg) Simultaneous atomic force- and 10:00 – 12:30, HS 15.03 scanning tunneling microscopy Energietag 11:00 – 11:20 “Mehr Licht” Coffee break AKE, PIE 11:20 – 12:30, HS 15.03 Prize Awards Ceremony Fritz Kohlrausch Prize, Victor Franz Hess Prize, Anton Paar Prize, Max Auwärter Prize, Roman Ulrich Sexl Prize, Young Physicists’ Tournament, Physics Olympiad, Physik-Fachbereichsarbeiten 12:45 – 13:30 12:30 – 13:30 Lunch Lunch break 13:30 – 14:30, HS 15.03 Prize Winner Talks Fritz Kohlrausch Prize 13:30 – 16:00, HS 15.03 Max Auwärter Prize Energietag Roman Ulrich Sexl Prize 13:30 – 16:00 “Mehr Licht” 14:30 – 15:30, HS 15.03 FAKT Plenary Talk LHS HS 15.02 Hans Briegel (Innsbruck) HS Quantum physics, simulation, 15.02 and computation 15:00, SR 15.15 15:30 – 16:00 ÖPG Board meeting Coffee break 16:00 – 16:45, HS 15.03 LHS Wolfgang Adam HS The Higgs Boson search at the LHC: 16:30 – 17:00, HS 15.03 results and perspectives 15.02 Opening 17:00 – 18:00, HS 15.03 16:45 – 17:45, HS 15.03 Plenary/Public Lecture ÖPG General Assembly James Cronin (Nobel Laureate) of Members Spontaneous Ionization to Subatomic Physics: Some Vignettes from Cosmic Ray History 17:45 – 20:00 Poster Session

19:00 Reception 20:15 – 21:15 Location: Rathaus Graz Theatre, HS 05.01 “Kosmische Strahlen: Das Leben des Victor F. Hess” 4 Programme of the 62nd Annual Meeting ÖPG 2012 Thursday, 20th September Friday, 21st September Registration: 08:30 – 16:30 Registration: 08:30 – 12:00

9:00 – 11:00 Parallel Sessions 9:00 – 11:00 AKU: LS 15.02 Parallel Sessions AMP: LS 15.01 FAKT: HS 15.03 FAKT: HS 15.03 FKP+NESY: HS 15.12 FKP+NESY: HS 15.12 OGD: HS 15.02 OGD: HS 15.02

11:00 – 11:30 11:00 – 11:30 Coffee break Coffee break 11:30 – 12:30, HS 15.03 Plenary Talk Vahid Sandoghdar (Erlangen) 11:30 – 13:30 On the efficient interaction of single Parallel Sessions photons and single emitters FAKT: HS 15.03 12:30 – 13:00 FKP+NESY: HS 15.12 Lunch break OGD: HS 15.02 13:00 – 14:30, HS 15.03 Careers in Physics HS 15.03 GEP: HS 05.01 ÖPG Scientific Commitees 14:30 – 15:30 and ÖPG Working Groups Parallel Sessions AKU, AMP, FAKT, FKP+NESY, OGD ACP: Equal Opportunities in Physics MBU: SR 15.15 AKE: Energy AKU: Acoustics 15:30 15:45 – AMP: Atoms, Molecules, Quantum Coffee break Optics and Plasmas FAKT: Nuclear and Particle Physics FKP: Solid State Physik 15:45 – 18:00 GEP: History of Physics LHS: Physics in Schools Parallel Sessions MBU: Medical Physics, Biophysics, AKU, AMP, FAKT, FKP+NESY, Environmental Physics GEP, OGD, MBU NESY: Research with Neutron and Synchrotron Radiation OGD: Surfaces, Interfaces, and Thin Layers 18:00 – 20:00 PIE: Physics - Industry - Energy Refreshments at the PMP: Polymer Physics UniGraz@Museum

Contents

1 Allgemeine Informationen / General information ...... 9

2 Plenary Sessions HS 15.03 ...... 15

3 Energy (AKE): Energietag “Mehr Licht!” HS 15.03 ...... 27

4 Nuclear and Particle Physics (FAKT) Tue: HS 15.02; Thu, Fri: HS 15.03 ...... 35

5 Physics Teachers (LHS) HS 15.02 ...... 61

6 Acoustics (AKU) LS 15.02 ...... 63

7 Atoms, Molecules, Quantum Optics and Plasmas (AMP) LS 15.01 ...... 73

8 Solid State Physics (FKP) & Research with Neutron and Synchrotron Radiation (NESY) HS 15.12 ...... 83

9 History of Physics (GEP) HS 05.01 (Physics Building) ...... 103

10 Medical, Bio and Environmental Physics (MBU) SR 15.15 ...... 109

11 Surfaces, Interfaces and Thin Films (OGD) HS 15.02 ...... 115

12 Careers in Physics (PIE) HS 15.03 ...... 133

13 Posters ...... 137

14 Contributors ...... 179

15 Maps ...... 187

7 8 1 Allgemeine Informationen / General information

Aktuelle Informationen k¨onnen von der Website der Konferenz abgerufen werden: http://www.oepg.at

Actual information can be downloaded from the conference website: http://www.oepg.at

Tagungsort Die Jahrestagung der Osterreichischen¨ Physikalischen Gesellschaft findet an der Karl-Franzens-UniversitätGraz, ReSoWi-Zentrum, Universitätsstrasse15 C, 8010 Graz, Osterreich,¨ statt. Das Tagungsbürobefindet sich fürdie Dauer der Jahresta- gung im Gang C. Den Campus- und Raumplan des ReSoWi-Zentrums finden Sie am Ende dieses Tagungsbandes. Die Theateraufführung“Kosmische Strahlen: Das Leben des Victor F. Hess” sowie die Sitzung der Arbeitsgruppe GEP (History of Physics) finden im Hörsaal05.01 des Physikinstitutes statt. Das UniGraz@Museum befindet sich im Hauptgebäude und ist über den Seiteneingang zu betreten (siehe Campusplan).

Vom Hauptbahnhof Graz aus kann die Universitätmit den Bussen 63 (Haltestelle “Universität”)oder 58 (Haltestelle “Mozartgasse”) erreicht werden (Fahrtdauer: 15– 25 Minuten). Die Haltestellen sind im Campusplan eingezeichnet. Des weiteren befinden sich vor dem Hauptbahnhof und vor dem Hauptgebäudeder UniversitätTaxis.

Conference venue The Annual Meeting of the Austrian Physical Society is held at the University of Graz, ReSoWi-Zentrum, Universitätsstrasse15 C, 8010 Graz, Austria. The conference office is situated at the entrance of the ReSoWi building, floor C, for the duration of the conference. A map of the campus and the ReSoWi center is added at the end of this book. The play “Kosmische Strahlen: Das Leben des Victor F. Hess” as well as the session of the working group GEP (History of Physics) take place in the lecture hall 05.01 of the physical institute. The UniGraz@Museum is situated in the main building and can be entered via the side entrance indicated in the campus map.

At the railway station of Graz (“Hauptbahnhof Graz”) take the bus 63 until to the bus stop “Universit¨at”or 58 to the stop “Mozartgasse” (time required: 15–25 minutes). Bus stops are indicated in the campus map. Moreover, in the front of the railway station as well as in front of the main building of the university are also taxi stands.

9 Tagungsgebühren/ Conference fees Kategorie Vor 31. Juli Nach 31. Juli Category Before 31 July After 31 July OPG¨ Mitglieder, assoz. Mitglieder EURO 70 EURO 80 OPG¨ members, assoc. members Mitglieder im Ruhestand EURO 35 EURO 40 OPG¨ retired members Nicht-Mitglieder EURO 90 EURO 100 OPG¨ non-members Lehrer Teacher EURO 15 EURO 20 Bachelor und Master Studenten Bachelor and Master students frei/free frei/free Doktoranden Ph.D. students EURO 15 EURO 20 Tagesgebühr Daily fee EURO 35 EURO 35 TagesgebührDoktoranden Daily fee for Ph.D. students EURO 10 EURO 10

Anmeldung und Zahlungsmodalit¨aten/ Registration and Pay- ment Bank¨uberweisung an / Payments should be made to: Universitaet Graz Bank Austria IBAN: AT32 1200 0500 9550 0605 BIC: BKAUATWW Verwendungszweck / Reference: OePG2012 + A28165301035 +participant’s names

Bei der Tagesrezeption: Es wird um Bargeld ersucht. Die Anmeldung vor Ort beginnt am Dienstag, 18. September 9:00–16:30, Mittwoch, 19. September 8:30– 16:30, Donnerstag, 20. September 8:30–16:30, und Freitag, 21. September 8:30–12:00 (siehe auch Tagungsprogramm).

At the conference registration: You are kindly requested to pay in cash at the registration. The registration times are as follows: Tuesday, 18th September 9:00– 16:30, Wednesday, 19th September 8:30–16:30, Thursday, 20th September 8:30–16:30, and Friday, 21st September 8:30–12:00 (see also program).

10 Reisekostenzuschuss fürstudentische OPG-Mitglieder¨ Studentische OPG-Mitglieder¨ könneneinen Reisekostenzuschuss mittels des im Ta- gungsbüroaufliegenden Formulars beantragen (Befürwortung durch Betreuer not- wendig). Die Höheder Zuschüsserichtet sich nach den zur Verfügungstehenden Mitteln, der Zahl der Ansuchen sowie der tatsächlichen Höheder Reisekosten.

Travel support for student members of the OPG¨ Student members of OPG¨ can apply for travel support via the form available at the registration. The signature (approval) of the applicants tutor is necessary on the form. The amount of support depends of the funds available, the number of applications and the actual travel costs.

Unterbringungsmöglichkeiten Unterkünftein Graz könnenüber http://www.booking.com oder über Graz Touris- mus, http://www.graztourismus.at, Tel. +43-316-8075-0, E-mail: [email protected] gebucht werden.

Accommodation Hotels can be booked via http://www.booking.com or the Tourist Oﬃce Graz, http://www.graztourismus.at, Tel. +43-316-8075-0, email: [email protected].

Hörsäleund Ausstattung Alle Hörsälesind mit einem PC und einem Beamer ausgestattet, sodass die Mit- nahme eines USB-Sticks genügt.Das Betriebssystem ist MS Windows XP mit Pow- erPoint als Standard-Präsentations-Software. Sollten Sie ein anderes Betriebssys- tem bzw. eine andere Präsentations-Software benötigen,so ist ein eigenes Notebook mitzubringen. Technische Unterstützungvor Ort ist möglich. Die Erfahrung zeigt, dass es bei den Beamer-Präsentationen immer wieder zu zeit- lichen Verzögerungenbeim Ablauf der Sitzungen kommen kann (Inkompatibilitäten von Soft- und Hardware, Nicht-Standard-Schriftsätze,etc.). Füreinen reibungslosen Ablauf der Fachsitzungen sind die Vorsitzenden der Fachausschüsseverantwortlich.

11 Lecture rooms and equipment All lecture rooms are equipped with computer and video projector for which you only need to bring your USB-stick. The operating system is MS Windows XP with PowerPoint as standard presentation software. Should you need another operation system resp. another presentation software it is recommended to supply your own laptop. Technical assistance will be available in the lecture rooms. Experience has proved that there are always delays with preparation of lectures due to incompatibility of software, etc. The chairmen of the topical sessions are respon- sible for the smooth operation of the session.

Poster Format: Breite max. 97 cm, Höhemax. 147 cm, bzw. A0 Format. Posters können bei Beginn der Tagung (Dienstag, 18. Sept. 2012) angebracht werden, und sollten möglichst bis zum Abend des 20. Sept. 2012 ausgestellt bleiben. Bei der allgemeinen Postersitzung am Mittwoch, 19. Sept. 2012, ab 17:45 Uhr, sollte mindestens ein Au- tor beim Poster anwesend sein.

Der Gewinner des Posterpreises, zur Verf¨ugung gestellt von EPL, wird zu Beginn des Plenarvortrages am Donnerstag um 11:30 bekanntgegeben.

Posters Format: Width: 97 cm, height 147 cm (A0 format). You can ﬁx your poster on the ﬁrst of day of the conference (Tuesday, 18 Sept. 2012). On Wednesday, 19th Sept. 2012, at 17:45 there should be at least one author presenting the poster at the general poster session.

The cash prize for the best poster will be announced on Thursday, at the begin- ning of the plenary talk at 11:30.

12 Buffets und Erfrischungen Das Buffet wird währendder Poster Session am Mittwoch von 17:45–20:00 Uhr geöffnetsein. Am Donnerstag, von 18:00–20:00 Uhr, werden im Museum der Karl- Franzens-Universität(UniGraz@Museum) Erfrischungen zur Verfügungstehen.

Buﬀets and Refreshments During the poster session on Wednesday, 17:45–20:00, food and drinks will be provided. Refreshments will be also provided at the University Museum (Uni- Graz@Museum) at the end of the Thursday sessions.

13 14 2 Plenary Sessions HS 15.03 Tuesday, 18th September 2012, HS 15.03 Time Presenter Title 16:30 Opening James Cronin Spontaneous Ionization to Sub- 17:00 (Nobel Laureate) atomic Physics: Some Vignettes from Cosmic Ray History

Wednesday, 19th September 2012, HS 15.03 Time Presenter Title Cosmic Rays: An Ongoing Clear 09:00 - 10:00 John Swain Window into New Physics Simultaneous atomic force- and scanning tunneling microscopy – 10:00 - 11:00 Franz Gießibl a new view on two distinct aspects of the atomic structure of matter

11:20 - 12:30 Prize Award Session

12:30 - 13:30 Lunch Break

Time Presenter Title Enhancing image contrast in Alexander Jesacher 13:30 - 13:40 Joint Fritz Kohlrausch Prize wide-field CARS microscopy by tailored phase matching Advances in understanding Daniel Kiener 13:40 - 13:50 Joint Fritz Kohlrausch Prize small-scale plasticity through in-situ TEM Giuseppe Mercurio Unfolding Molecule-Metal Inter- 13:50 - 14:10 Max AuwärterPrize actions using X-ray Standing Waves Physik erfahren, Physik erleben Nicolette Doblhoff-Dier 14:10 - 14:30 Roman Ulrich Sexl Prize – auf vielen Wegen zur Physik

Quantum physics, simulation 14:30 - 15:30 Hans Briegel and computation 15:30 - 16:00 Coﬀee break

15 Wednesday, 19th September 2012, HS 15.03 Time Presenter Title The Higgs Boson search at the 16:00 - 16:30 Wolfgang Adam LHC - results and perspectives

16:45 - 17:45 OPG¨ General Assembly of Members

17:45 - 20:00 Poster Session (see chapter Posters)

20:15 Theatre (see page 22), HS 05.01, Physics Building

Thursday, 20th September 2012, HS 15.03 Time Presenter Title On the eﬃcient interaction of 11:30 - 12:30 Vahid Sandoghdar single photons and single emitters

16 Tue, 17:00 - 18:00, HS 15.03

Tue, 17:00, Plenary Spontaneous Ionization to Subatomic Physics: Some Vignettes from Cosmic Ray History James Cronin1,2 1The University of Chicago,The Kavli Institute for Cosmological Physics, 933 East 56th Street, Chicago, IL 60637 USA 2Enrico Fermi Institute, University of Chicago, 5640 S. Ellis Avenue, RI-183, Chicago, IL 60637 USA

In the 1879 Crookes discovered that air seemed to ionize spontaneously. With the discovery in 1896 of radioactivity by Henri Becquerel it appeared that the mystery was solved. However a number of physicists sought a quantitative agreement between the “spontaneous ionization” and the radioactivity in the earth. The persistence of these physicists led to the discovery of another source of radiation which appeared to come from the heavens. The nature of this “cosmic radiation” involved phenomena that were completely unknown. Coming to an understanding of the nature of this cosmic radiation took about 40 years between 1912 and 1953. This history involves extraordinary scientists and the invention of dramatic new detection techniques. The story finishes with a remarkable conference organized by Patrick Blackett and Louis Leprince-Ringuet 1953 in the Pyrenees town of Bagneres de Bigorre. James Cronin and co-researcher Val Logsdon Fitch were awarded the 1980 Nobel Prize in Physics for a 1964 experiment that proved that certain subatomic reactions do not adhere to fundamental symmetry principles. Specifically, they proved, by examining the decay of kaons, that a reaction run in reverse does not merely retrace the path of the original reaction, which showed that the interactions of subatomic particles are not indifferent to time. Thus the phenomenon of CP violation was discovered. Cronin received the Ernest Orlando Lawrence Award in 1976 for major experimental contributions to particle physics including fundamental work on weak interactions culminating in the discovery of asymmetry under time reversal. He is Professor Emeritus at the University of Chicago and a spokesperson emeritus for the Auger project. The Pierre Auger Ob- servatory, which he proposed, is an international cosmic ray observatory spread over 3000 square kilometers in Argentina, designed to detect ultra-high-energy cosmic rays.

Wed, 09:00 - 10:00, HS 15.03

Wed, 09:00, Plenary Cosmic Rays: An Ongoing Clear Window into New Physics John Swain1 1Northeastern University, Physics Department, 360 Huntington Ave, 111 Dana Research Center, Boston, MA 02115, USA

Since Victor Hess’s pioneering work in 1912, cosmic rays have provided not only a window into energetic processes in space, but also the first glimpses of many aspects of particle physics. This talk reviews and highlights some of the major achievements in the field, what has been learned, and what major scientific puzzles remain, emphasizing the uniqueness of cosmic rays as a probe of both exotic objects in the far reaches of the universe, and into the deep heart of matter beyond the reach of even modern terrestrial particle accelerators. An outlook for the future is given showing that cosmic ray physics will continue to provide key insights into nature unavailable through any other means.

17 Wed, 10:00 - 11:00, HS 15.03

Wed, 10:00, Plenary Simultaneous atomic force- and scanning tunneling microscopy – a new view on two distinct aspects of the atomic structure of matter Franz Gießibl1 1University of Regensburg, Faculty of Natural and Applied Physics II - Physics, Universit¨atsstrasse 31, D-93053 Regensburg, Germany

Frequency-modulation AFM can be combined with scanning tunneling microscopy, yielding a simultaneous data set for current and average force gradient. Ternes et al. [1] have shown that for some metallic contacts, force and current are proportional. The figure below [2] shows an example, where combined AFM/STM reveals two strongly distinct aspects of the atomic structure of matter. The gray veil depicts the inverted tunneling current between a CO molecule adsorbed on Cu(111) and a tungsten tip, while the colored surface shows the corresponding force profiles, where the left image corresponds to a W tip oriented in a h100i direction, the right to a h110i direction and the bottom to a h111i direction [3]. While the simultaneous acquisition of current and force can reveal new information about the atomic and electronic structure of matter, the tunneling current can modify the atomic forces. This “phantom force” [4,5], a modification of the electrostatic attraction between tip and sample, originates in an alteration of the effective potential difference between tip and sample caused by strongly localized voltage drop induced by the tunneling current. The talk discusses the merits of combined STM/AFM as well as the challenges, in particular with respect to tip preparation and characterization.

[1] M. Ternes et al., Phys. Rev. Lett. 106, 016802 (2011). [2] Created by Joachim Welker (2012). [3] J. Welker, F.J. Giessibl, Science 326, 444 (2012). [4] A.J. Weymouth et al. Phys. Rev. Lett. 106, 226801 (2011). [5] T. Wutscher et al. Phys. Rev. B 85, 195426 (2012).

Wed, 11:00 - 11:20, Coﬀee break

Wed, 11:20 - 12:30, HS 15.03, Prize Award Session Fritz Kohlrausch Prize, Victor Franz Hess Prize, Anton Paar Prize, Max Auw¨arterPrize, Roman Ulrich Sexl Prize, Young Physicists’ Tournament, Physics Olympiad, Physik-Fachbereichsarbeiten

18 Wed, 12:30 - 13:30, Lunch break

Wed, 13:30 - 14:30, HS 15.03, Prize Winner Talks

Wed, 13:30, Joint Fritz Kohlrausch Prize Winner Enhancing image contrast in wide-ﬁeld CARS microscopy by tailored phase matching Alexander Jesacher1, Clemens Roider1, Saranjam Kahn1, Gregor Thalhammer1, Stefan Bernet1, Monika Ritsch-Marte1 1Innsbruck Medical University, Division of Biomedical Physics, M¨ullerstrasse 44, 6020 Innsbruck, Austria

Coherent anti Stokes Raman scattering (CARS) is a four-wave mixing process that allows identifying the chemical composition of target substances by recording their molecular vibrational spectra. Combined with microscopy, this technique opens a door to investigating specimens at micrometer scale. A sensitivity limit in CARS microscopy is commonly set by the non-resonant backgrounda parasitic signal component that arises from off-resonantly driven molecular vibrations and/or electronic transitions. In particular for the application of investigating small particles, the non-resonant background generated in the immersion liquid can easily overwhelm the signal of the particles. We introduce a wide-field CARS microscope implementation that allows for effective suppression of the solvent signal by precisely controlling the pump/probe beam incidence angles. Our method relies on the fact that the importance of phase-matching for CARS increases with the size of the target object. Thus, de-tuning these angles by only as much as a degree can lead to a significant loss in the undesired solvent signal while leaving that of the particles almost unaltered. We present experimental results where the ratio of the signals of 500nm polystyrene beads and the surrounding solvent was improved by a factor of about 100.

Wed, 13:40, Joint Fritz Kohlrausch Prize Winner Advances in understanding small-scale plasticity through in-situ TEM Daniel Kiener1 1Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

The uncommon mechanical properties of small volumes, in particular their size-dependent strength and hardening behavior, have received significant interest over the last few years. To exploit these effects for future design of nano-structured materials, it is detrimental to understand the underlying deformation mechanisms that govern the observed sample size effects in micron- and sub-micron dimensions. Miniaturized tensile and compression samples were fabricated using a focused ion beam microscope and tested in-situ in a transmission electron microscope. Besides providing precise mechanical data, such highly localized in-situ experiments allow to directly observe the dynamics of crystal defects in real time, and to correlate them to the mechanical signature, thereby delivering valuable insight regarding the governing strengthening mechanisms. It is shown that plastic deformation is governed by the operation of spiral dislocation sources at high stresses. The hardening behavior correlates directly to the exhaustion of such dislocation sources and the ability to create new sources by dislocation interaction. Finally, it is demonstrated that an internal micro-structural length scale smaller than the sub-micron sample size causes a transition from size-dependent to size-independent material properties, allowing to measure bulk properties from nano-scale samples.

19 Wed, 13:50, Max Auw¨arterPrize Winner Unfolding Molecule-Metal Interactions using X-ray Standing Waves Giuseppe Mercurio1,2

1Peter Grünberg Institut (PGI-3), Forschungszentrum Jülich,52425 Jülich,Germany 2JülichAachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Jülich,Germany

Functional surfaces based on monolayers of organic molecules are currently subject of an intense research effort due to their applications in molecular electronics, sensing and catalysis. Because of the strong dependence of organic-based devices on the local properties of the molecule-metal interface, a direct investigation of the interface chemistry is of paramount importance. In this context, the bonding distance, measured by means of the normal incidence x-ray standing wave technique (NIXSW), provides a direct access to the molecule-metal interactions. At the same time, NIXSW adsorption heights are used to benchmark different density functional theory (DFT) schemes and determine the ones with predictive power to be employed for similar systems. The talk will focus on three molecule-metal interfaces pointing out the physical properties common to other metal-organic systems. The study of a multifunctional organic molecule (perylenetetracarboxylic acid dianhydride, PTCDA) adsorbed on the Ag(110) surface reveals the presence of two distinct bonding channels which depends on the affinity of the respective part of the molecule towards the substrate. The coupling between these bonding channels is probed by means of a local modification of the Ag(110) surface through alkali induced reconstruction. The delicate balance of intermolecular and molecule-substrate interactions for terephthalic acid adsorbed on Cu(100) is investigated by a combined NIXSW-DFT study that suggests the presence of a substrate-mediated interaction, besides the intermolecular H-bonding, as stabilizing force of the molecular islands. Finally, with the aim to better understand the switching properties of photo-active molecules (azobenzene derivatives) adsorbed on metal surfaces, a novel NIXSW analysis scheme, developed to determine the bonding conformation of complex organic molecules adsorbed on single metal crystals with unprecedented accuracy, is presented.

Wed, 14:10, Roman Ulrich Sexl Prize Winner Physik erfahren, Physik erleben – auf vielen Wegen zur Physik Nicolette Doblhoﬀ-Dier1 1AHS-Professorin f¨urPhysik, Mathematik und Informatik, Gymnasium Maria-Regina, 1190 Wien

Physik im Unterricht soll Interesse, ja sogar Begeisterung hervorrufen, Neugier wecken, genaues Beobachten lehren, logisches Denken fördern,zum Nachdenken und Fragen anregen, Diskussionen vom Zaun brechen und Begreifen ermöglichen. Physik im Unterricht soll neue Welten eröffnen, Zusammenhängezeigen und Brücken schlagen. SchülerInnenwollen in ihren Interessen angesprochen werden und erkennen, dass Physik überall ist, in der Geschichte, Kunst und Religion (Projekt “Physik im Stephansdom”), in der Musik und Mathematik (“Was macht das Klavier wohltemperiert?”), in der Medizin (“Hochenergie und Med-Austron”), ja sogar beim Vereinbaren von Terminen (“Von Sonnenuhren über die gregorianische Kalenderreform bis zur Atomuhr”). Einen Schwerpunkt des Vortrags bildet das Projekt “Die vielen Gesichter des Sir Isaac Newton”, in Kooperation mit der Osterreichischen¨ Akademie der Wissenschaften, im Rahmen dessen zahlreiche wissenschaftliche Plakate entstanden, sowie fiktive Zeitungsartikel, Fernsehdiskussionen und Rätsel,die das Leben von Newton aus unterschiedlichen Blickwinkeln betrachten. Die SchülerInnen schauten staunend durch die gebastelten Fernrohre und Mikroskope und diskutierten heftig über die von ihnen übersetzten Originaltexte von Isaac Newton aus dem Trinity-College und Voltaires Buch “Les elémensde la philosophie de Neuton”. Ich möchte zeigen wie wichtig es ist, den SchülerInnen viele unterschiedliche Wege zur Physik zu ermöglichen. Ich möchte sie lehren zu fragen und zu staunen!

20 Wed, 14:30 - 15:30, HS 15.03

Wed, 14:30, Plenary Quantum physics, simulation, and computation Hans Briegel1

1Universit¨atInnsbruck, Institut f¨urTheoretische Physik, Technikerstrasse 25, 6020 Innsbruck, Austria

The ultimate scope and power of computers will be determined by the laws of physics. Quantum computers exploit the rules of quantum mechanics, using quantum coherence and entanglement for new ways of information processing. Up to date, the realization of these systems requires extremely precise control of matter on the atomic scale and a nearly perfect isolation from the environment. The question, to what extent quantum information processing can also be exploited in “natural” and less controlled systems, including biological ones, is exciting but still open. In this talk, I will present some of our recent work on (quantum) physically and biologically motivated models of information processing.

Wed, 16:00 - 16:45, HS 15.03

Wed, 16:00, Plenary The Higgs Boson search at the LHC - results and perspectives Wolfgang Adam1

1Austrian Academy of Sciences, Nikolsdorfergasse 18, 1050 Vienna, Austria

Two experiments have recently announced the discovery of a new boson with a mass near 125 GeV at the CERN LHC. This new particle matches the expectations for the Higgs boson, the missing piece of the Standard Model of particle physics, which has been one of the main targets of experiments in the last decades. This talk will give details on the experimental evidence, focussing on results of the Compact Muon Solenoid (CMS) experiment. First measurements of the properties of the new particle will be compared to the expectations of the Standard Model. The fundamental implications of the existence of a Higgs boson for particle physics will be explained. The plans for further measurements of the properties of this boson and the implications for discovery of Physics beyond the Standard Model will be discussed.

21 Wed, 20:15, HS 05.01 (Physics Building)

Wed, 20:15, HS 05.01 (Physics Building), Theatre Play Kosmische Strahlen - Das Leben des Victor F. Hess Klaus Reitberger1, Stadttheater Kufstein1

1http://www.stadttheater-kufstein.at/de/index.php

Insights into the eventful life and scientific struggle of Victor F. Hess are presented in this one-hour play. Based on historic accounts and personal letters, the unique character of the much acclaimed scientist is portrayed through several key episodes of his life. From the famous balloon- flight in 1912 to the research at the Hafelekar-observatory high above Innsbruck, from receiving the Nobel prize in physics to the dramatic escape from Nazi-Germany on the eve of World War II. Written and directed by a physicist and performed by actors of the Stadttheater Kufstein [1], this project attempts to let history and science meet on stage. The play has already been performed in Vienna, Innsbruck and Kufstein. Further performance are foreseen in Pöllau, Siegen, Berlin and Hamburg. A six-minute video-trailer of the play can be viewed on [2]. The play will be performed in German. An English translation will soon be published by University Press Innsbruck. The German script is already available. [1] http://stadttheater-kufstein.at/de/kosmische strahlen.php [2] http://www.youtube.com/watch?feature=player embedded&v=4 8Udh2HoW8.

22 23 Thu, 11:30 - 12:30, HS 15.03

Thu, 11:30, Plenary On the eﬃcient interaction of single photons and single emitters Vahid Sandoghdar1

1Max-Planck Institut, G¨unther-Scharowsky-Strasse 1 / Bau 24, 91058 Erlangen, Germany

In the 1990s, many pioneering experiments demonstrated the potential of single organic molecules embedded in solids as quantum mechanical two-level systems. However, coherent interactions were not studied because those experiments relied on recording the fluorescence signal, which only ac- cesses populations of the excited state and not the coherences. Recently, we showed theoretically that in the linear excitation regime, an atom can block a propagating light beam by up to 100% if it is confined to an area comparable with its scattering cross section [1]. I will present an overview of our recent experimental work on the efficient interaction of light and single organic molecules both in the near and far fields [2, 3]. We will see that at T<2K, a single molecule can attenuate [2, 3], transmit, amplify [4] or phase-shift [5] a focused laser beam. Furthermore, I will report on the first direct long-distance communication of two optical emitters via single photons [6]. I will then discuss strategies for the optimization of the interaction between single photons and single emitters via, e.g. ultra-high collection efficiency [7, 8] or enhancement of spontaneous emission [9] by using plasmonic and dielectric antennas. [1] G. Zumofen, et al., Phys. Rev. Lett. 101, 180404 (2008). [2] I. Gerhardt, et al., Phys. Rev. Lett. 98, 033601 (2007). [3] G. Wrigge, et al., Nature Phys. 4, 60 (2008). [4] J. Hwang, et al., Nature 460, 76 (2009). [5] M. Pototschnig, et al. Phys. Rev. Lett. 107, 063001 (2011). [6] Y. Rezus, et al., Phys. Rev. Lett. 108, 093601 (2012). [7] K-G. Lee, et al., Nature Photonics 5, 166 (2011). [8] X-W. Chen, S. Götzinger,V. Sandoghdar, Opt. Lett. 36, 3545 (2011). [9] X-W. Chen, M. Agio, V. Sandoghdar, Phys. Rev. Lett. 108, 233001 (2012).

24 25 26 3 Energy (AKE): Energietag “Mehr Licht!” HS 15.03

AKE: Norbert Pillmayr, [email protected]

Tuesday, 18th September 2012, HS 15.03 Time Presenter Title Mehr Licht! – Das Vorwort zum En- 10:00 - 10:15 Norbert Pillmayr ergietag 2012 Bio-analoge Energie- und Material- 10:15 - 10:45 Helmut Tributsch wirtschaft Strom fürdie Welt – und wie uns die 10:45 - 11:15 Robin Hirschl Sonne dabei helfen kann Bedarfsgerecht und energieeffizient 11:15 - 11:45 Thomas Posch beleuchten Das kann Sonnenschutz: Energie, 11:45 - 12:15 Johann Gerstmann Licht und Wärme– zum Nulltarif! 12:15 - 12:45 Günther Leising Leuchtdioden verändernunsere Welt

12:45 - 13:30 Lunch

“Oma Glühbirne, Enkerl LED und der 13:30 - 13:50 HAK/HAS Mistelbach wilde Onkel Scheinwerfer erzählen” LED – Die Lichtquelle der Zukunft rev- 13:50 - 14:20 Dieter Parth olutioniert auch die Automobilindus- trie! PHOTO-TEKTUR: Qualitativer 14:20 - 14:50 Gregor Radinger Lichteintrag und photobiologische Grundlagen fürArchitektInnen 14:50 - 15:20 Wilfried Pohl Licht und Energie im Gebäude Smart Lighting for Smart Citizens – 15:20 - 15:50 Mathias Schaffer Mehr Licht !? und innovative Beleuch- tungskonzepte fürSmart Cities 15:50 - 16:00 Norbert Pillmayr Schlussworte

Tue, 10:00 - 12:45, HS 15.03

27 Tue, 10:00 Mehr Licht! - Das Vorwort zum Energietag 2012 Norbert Pillmayr1

1KELAG - K¨arntnerElektrizit¨ats-Aktiengesellschaft, Klagenfurt, Austria

Nach den Energietagen 2010 in Salzburg (Thema: Realisierung der Klimaziele) und 2011 in Wien mit dem Schwerpunkt “Energie effizient nutzen” ist 2012 in Graz die – oftmals unter- schätzte– Thematik der Lichtenergie das Hauptthema des Energietags. Licht macht ca. 20% des weltweiten und 14% des europäischen Stromverbrauchs aus. Diverse Innovationen in der Lichttech- nik könnenbei der Erreichung der Kyoto-Ziele helfen, da Kosten gespart, die Umwelt geschütztund die Beleuchtungsqualitätverbessert werden. Licht kommt eine wesentliche Bedeutung fürKom- fort, Emotion, Motivation und Leistungsbereitschaft zu. In gewerblich genutzten Gebäudenwie Produktions-, Verkaufs- und Bürogebäudenentfallen zwischen 30% und 40% auf Energiekosten. Hier könnendurch eine effiziente Lichtgestaltung Energieeinsparungen erzielt und somit Betrieb- skosten gesenkt werden. Energieeffiziente Beleuchtung leistet damit einen wesentlichen Beitrag zur Erreichung der Klimaziele. Die Umwelt wird durch verringerten Energieverbrauch und einer Re- duktion der Kohlendioxydbelastung geschont, Kosten werden gesenkt und die Lichtqualitätfürdas Wohl des Menschen wird gleichzeitig verbessert. Der Arbeitskreis (AK) Energie ist ein sehr aktiver Arbeitskreis in der Osterreichischen¨ Physikalischen Gesellschaft (OPG),¨ der Interessensvertretung der Physiker in Osterreich.¨ Ein dreiköpfigerVorstand vertritt gleichberechtigt Wissenschaft, Indus- trie und Lehre. Zentrales Thema des AK Energie ist die Behandlung der physikalischen Aspekte und Perspektiven von Energiefragen unter besonderer Berücksichtigung der österreichischen Situ- ation. Diese sollen in Zusammenarbeit mit Vertretern aller relevanten Fachrichtungen diskutiert werden. Es wird vor allem Konsens in der Einschätzungder naturwissenschaftlich–technologischen Aspekte der Energieproblematik angestrebt.

Tue, 10:15 Bio-analoge Energie- und Materialwirtschaft Helmut Tributsch1,2 1Freie UniversitätBerlin, Takustraße 3, 14195 Berlin, Germany 2Helmholtz-Zentrum Berlin fürMaterialien und Energie Kekuléstrasse 5, 12489 Berlin, Germany

Die Menschheit hätteeine reelle Chance, durch massive Forschung, über eine solar betriebene Energie-Wirtschaft, längerfristigins Gleichgewicht mit der Natur zurück zu finden. Das von der Natur vorgegebene und über Hunderte von Jahrmillionen Jahren bewährteVorbild beinhaltet die Spaltung von Wasser mit Licht und die Anhaftung des freigesetzten Wasserstoffs an einen Kohlenstoff-Träger,Kohlendioxid, zur Bereitstellung von Energieträgernund Baustoffen. Die Um- setzung dieser Produkte durch die Pflanzen- und Tierwelt führtzu geschlossenen, nachhaltigen Energie-Stoff-Kreisläufen.Sie wird wirksam unterstütztdurch eine Reihe bisher von unserer Tech- nik nicht beherrschte beziehungsweise nicht erschlossenen Technologien. Sie reichen von “kinetisch” funktionierenden Solarzellen, zu photo-katalytischer Wasserspaltung, Kohlendioxid-Fixierung, zu effektiver Energie-Katalyse und “tensiler” Wasser-Technologie. Es wird analysiert, wie die Men- schheit sich diesen von der Natur realisierten Zielen mit zunächst vereinfachten Techniken schrit- tweise annähernkönnte. Angelpunkt wäreanfangs die massive Bereitstellung von billigem Wasser- stoff, der dann mit vergaster Biomasse zu nachhaltigen Brenn- und Rohstoffen verbunden werden könnte. Die gegenwärtigeBrennstoff-Infrastruktur bliebe im Wesentlichen erhalten. Der Einstieg in diese Natur-nahe Strategie besteht darin, die Quellen höchster nachhaltiger Energiedichte, die stürmischen Meere, fürdie Wasserstoff-Gewinnung zu nutzen. Dies wäreüber eine Unter-Wasser- Technologie denkbar, bei der nur die sich mit den Wellen bewegenden, energiewandelnden Bojen an die Wasseroberfläche reichen. Diese Wasserstoff- Technologie sollte in zwei bis drei Jahrzehnten re- alisierbar sein. Weitere nötige und nützliche Technologien in Richtung einer bio-analogen, globalen Energiewirtschaft könnten innerhalb dieses Jahrhunderts verfügbarsein. Die Herausforderungen und Vorteile werden diskutiert.

28 Tue, 10:45 Strom f¨urdie Welt – und wie uns die Sonne dabei helfen kann Robin Hirschl1 1ENcome Energy Performance GmbH, Klagenfurt, Austria

Die Sonne: Ein gigantischer Kernfusionsreaktor, 150 Millionen Kilometer von der Erde entfernt. Und trotz der Entfernung liefert dieser Reaktor jährlich mehr als das 10.000-fache des weltweiten Bedarfs an Primärenergie.Im Vortrag sollen zunächst die verschiedenen Möglichkeiten solare En- ergie zu nutzen diskutiert werden. Anschließend wird auf die physikalischen und wirtschaftlichen Details der Photovoltaik nähereingegangen. Sowohl der derzeitige Stand der Technik als auch die theoretischen Grenzen der Technologie werden beschrieben. In weiterer Folge soll mit einigen Vorurteilen rund um die Photovoltaik aufgeräumt werden, wie zum Beispiel dass die Photovoltaik bei der Erzeugung mehr Energie verbraucht als währendder Lebensdauer der Anlagen produziert wird, oder dass die Photovoltaik nicht ohne Subventionen wirtschaftlich sein kann. Im zweiten Teil werden, ausgehend von den derzeitigen technischen und ökonomischen Auswirkungen der Imple- mentierung von PV Anlagen in europäische Stromnetze, die Möglichkeiten und Herausforderun- gen von signifikanten PV Kapazitätenim Netzverbund behandelt. Insbesondere mangelt es noch an einer effizienten und langzeitstabilen Möglichkeit zur Energiespeicherung, um Photovoltaik in lokalen autarken Netzen exklusiv einsetzen zu können. Andererseits könnengrößereGruppierun- gen von PV Anlagen schon jetzt dazu beitragen, einige der technischen Schwierigkeiten heutiger Verteil- und Ubertragungsnetze¨ zu meistern. Abschließend soll ein Blick in die Zukunft helfen zu verstehen, welche Möglichkeiten realistisch in der Solarenergie stecken und in welchem Kontext eine echte Energiewende hin zu erneuerbaren Energien tatsächlich möglich erscheint.

Tue, 11:15 Bedarfsgerecht und energieeffizient beleuchten Thomas Posch1 1UniversitätWien, Universitätsring1, 1010 Wien, Austria

Künstliche Beleuchtung macht unser Leben (scheinbar) leichter: die Gestaltung unserer Arbeits- und Freizeit wird flexibler, sogenannte “Angsträume”verschwinden, Produktionsvorgängekönnen - auch ohne Mitternachtssonne - 24 Stunden und 7 Tage pro Woche aufrecht erhalten werden. Erst in den letzten Jahren hat sich durch wissenschaftliche Untersuchungen gezeigt, dass künstliches Licht nicht immer und in jeder Menge dem Menschen und der Natur gut tut. Chronobiologen, En- tomologen, Ornithologen, aber auch Lichttechniker fanden heraus, dass künstliche Beleuchtung mit Maß und Ziel eingesetzt werden sollte - im Innen- wie im Außenraum. Das “Glühlampenverbot” der EU rückte Licht als bedeutenden Faktor im Energiekonsum in unser Bewusstsein (wenn auch auf unglückliche Weise!). Der Vortrag zeigt, dass und wie Beleuchtung nicht nach dem “Gießkannen- prinzip”, sondern bedarfsgerecht erfolgen sollte. Es wird auch darauf aufmerksam gemacht, dass Energieeffizienz alleine nicht zu umfassend “besserem Licht” führt.Grundlage der Ausführungen ist das Buch “Das Ende der Nacht – Die globale Lichtverschmutzung und ihre Folgen” von Thomas Posch, Anja Freyhoff, Thomas Uhlmann (Hg.) Wiley-VCH Verlag, Weinheim 2010.

29 Tue, 11:45 Das kann Sonnenschutz: Energie, Licht und W¨arme- zum Nulltarif! Johann Gerstmann1 1Bundesverband Sonnenschutztechnik Osterreich,¨ Guntramsdorf, Austria

Um solare Energie richtig nutzen zu können, muss die Kraft der Sonne je nach Tages- und Jahreszeit sowie entsprechend bautechnischer Parameter wie Raumnutzung, Bauweise, Glasqualität, Fensterflächen-anteil, Orientierung der Fassaden, bedarfsgerecht geregelt werden. So wie ein Ther- mostatventile die Heizung regelt, so sollte temporärerund intelligent gesteuerter Sonnenschutz den Wärmeeintrag über Fenster und Glasfassaden regeln. Im Gegensatz zur Notwendigkeit den En- ergieeintrag dem Außenklima anzupassen, gilt es diffuses Tageslicht maximal zu nutzen – füreine hohe Tageslichtautonomie im Sinne der Energieeffizienz aber vor allem in Hinblick darauf, dass die Wirkung von Tageslicht auf den Menschen durch Kunstlicht nicht ersetzt werden kann. Vor Sonne schützenaber gleichzeitig Tageslicht nützenmuss kein Widerspruch sein, ist aber eine spannende Herausforderung sowohl fürdie Architektur als auch fürdie Industrie! Sonnenschutz ist eine passive Technologie um thermischen und visuellen Komfort in Gebäudenbei geringstem Energiebedarf zu sichern. Neben Photovoltaik und Solarthermie ist die Sonnenschutztechnik - also das Managen des Energie- und Lichteintrages über transparente Flächen – die dritte aber inoffizielle Säulesolarer Energienutzung, die zum Erreichen der EU 20-20-20 Ziele noch eine große Rolle spielen kann.

Tue, 12:15 Leuchtdioden ver¨andernunsere Welt G¨unther Leising1

1Technische Universit¨atGraz, Petersgasse 16/1.Sotck, 8010 Graz, Austria

Wir sehen mit unseren Augen Licht im Bereich von violett (400 nm) bis rot (750 nm). Da jeder Mensch ein individuelles Lichtempfinden hat, wurde fürden technischen Vergleich ein “Normauge” festgelegt, das bei 555 nm (grün)die maximale Sehempfindlichkeit hat. Damit wir alle Farben eines Objekts tatsächlich wahrnehmen können,muss die Lichtquelle mit der es beleuchtet wird, Licht aller Farben im Bereich des Sichtbaren aussenden. Nur die Glühbirne (und die Halogenlampe) hat- ten bisher annähernddiese Eigenschaft. LED sind kleine (typisch 0.3x0.3 mm), dünn-schichtweise aufgebaute Festkörper-Lichtquellen die mit Spannungen einiger Volt betrieben werden. Mit einer blauen, grünenund roten LED oder mit einer blauen LED und neuartigen Farbstoffumhüllungen kann praktisch Licht aller Farben und auch weißes Licht mit hoher Farbwiedergabequalitäterzeugt werden. Wichtige Eigenschaften neben der Farbwiedergabe einer Lichtquelle sind die Effizienz (Lu- men/Watt) und die Farbtemperatur in Kelvin (K). Eine Glühbirne hat eine Effizienz von 10 bis 15 lm/W und je nach Betrieb Farbtemperaturen zwischen 2700K und 6500K. Die Effizienz einer Halogenlampe liegt bei 20 lm/Watt. Energiesparlampen und Leuchtstoffröhrenhaben typischer- weise um die 80 lm/W. Gute “weisse” LEDs liegen derzeit zwischen 70 und 100 Lumen/Watt und das erreichbare Ziel fürLEDs liegt bei 200 Lumen/Watt. Die anvisierte Lebensdauer von LED Lichtquellen liegt weit über 50.000 Stunden. Mit der LED Technologie erlebt die Lichttechnik und damit die Beleuchtung eine längstfälligeErneuerung und Bereicherung.

30 Tue, 12:45 - 13:30: Lunch

Tue, 13:30 - 16:00, HS 15.03

Tue, 13:30 “Oma Gl¨uhbirne, Enkerl LED und der wilde Onkel Scheinwerfer erz¨ahlen” Mistelbach HAK/HAS1

1HAK/HAS Mistelbach, Brennerweg 8, 2130 Mistelbach, Austria

Vorstellung und Diskussion (Film der HAK/HAS Mistelbach)

Tue, 13:50 LED – Die Lichtquelle der Zukunft revolutioniert auch die Automobilindustrie! Dieter Parth1 1Inﬁneon Technologies Austria AG, Application Specialist Power LED Drivers, Villach, Austria

Die Verwendung von LEDs ist heute einer der Designtrends im Automobilbereich, um den Wiedererkennungswert unterschiedlicher Automarken zu steigern. Mittlerweile sind jedoch die Leuchtstärken der LEDs so hoch, dass auch Auf- und Abblendlichter und damit komplette Voll- LED Scheinwerfer Lösungen realisiert werden können.Der LED Trend beschränkt sich nicht nur auf die Fahrzeugaußenbeleuchtung. Im Fahrzeuginnenraum wird durch die Verwendung von RGB LEDs eine individuelle Anpassung der Innenbeleuchtung möglich. Aufgrund der kleinen Baugröße, der geringen Stoßempfindlichkeit sowie hohen Effizienzen werden völligneuartige LED-Lichtdesigns möglich. Die Lebensdauer von LEDs (50.000 Stunden) ist bei richtiger Handhabung um ein Vielfaches höherals bei gewöhnlichen Glühlampen (1000 Stunden). Gerade bei Heckleuchten profitiert man vom schnellen Ansprechverhalten der LEDs, welche beim Anzeigen des Bremsvorganges einen Sicherheitsvorteil bieten. Intelligente Halbleiterlösungenzur Ansteuerungen von Glüh-oder Halogenlampen haben bereits lange Tradition beim Villacher Chiphersteller Infineon - er ist seit Jahren Marktführerauf diesem Gebiet. Die Infineon AUTO LED Familie beinhaltet Produkte zur Ansteuerung von LED Licht-Funktionen. Deren Hauptaufgaben sind die genaue Regelung des zur Funktion benötigtenLaststromes, die Diagnose und der Schutz der Lasten vor Ubertemperatur¨ und Boardnetzschwankungen. Dass sich der LED Trend auch im Automobil voll durchsetzt zeigen bereits zahllose Beispiele auf unseren Straßen. Laut Experten soll es im Jahr 2030 bereits keine Glühbirnen mehr im Auto geben. Infineon trägtmaßgeblich zur Entwicklung und Markteinführung von LED-Beleuchtungslösungenim Automobil bei.

31 Tue, 14:20 PHOTO-TEKTUR: Qualitativer Lichteintrag und photobiologische Grundlagen f¨urArchitektInnen Gregor Radinger1

1Donau-Universit¨atKrems, Department f¨urBauen und Umwelt, Dr.-Karl-Dorrek-Straße 30, 3500 Krems, Austria

Hintergrund: Beim Durchgang durch Verglasungen werden wesentliche Bereiche des solaren Strahlungs-spektrums ausgefiltert. Natürliches Licht, das derart spektral ausgedünnt den Innen- raum erreicht, ist aus humanphysiologischer Sicht reduziert oder gar nicht wirksam. Vor diesem Hintergrund werden tatsächliche Gegebenheiten der Tageslichtversorgung in Innenräumen,mit Fo- cus auf den ultravioletten und sichtbaren Spektralbereich aufgezeigt. Planungsrelevanz: Aufbauend auf diesen Erkenntnissen werden Empfehlungen fürphotobiolo- gisch notwendige Eigenschaften von transparenten Bauteilen und gesundheitsförderlicher Raumkon- figurationen erstellt. Darüber hinaus wird die Bedeutung direkter und diffuser Lichteinträgeauf die qualitative Wahrnehmung von Räumenuntersucht, um den wichtigen Stellenwert von Licht für die allgemeine Akzeptanz von Architektur zu unterstreichen.

Vortragsthemen: • Strahlungsangebot im Außenraum • Strahlungsangebot im Innenraum • Visuelle und nicht visuelle Lichtwahrnehmung • Qualitative Raumwahrnehmung bei diﬀusem und direktem Lichteintrag • Ableitungen f¨urarchitektonische Entwurfsstrategien

Tue, 14:50 Licht und Energie im Geb¨aude Wilfried Pohl1 1Bartenbach LichtLabor GmbH, Aldrans, Austria

Im Vortrag wird die Rolle des Lichtes fürden Energiehaushalt eines Gebäudeserläutert.Dabei spielt nicht nur die elektrische Beleuchtung sondern insbesondere auch die Tagesbelichtung eine wichtige Rolle. Es wird ein Uberblick¨ und Ausblick über energiesparende Beleuchtungstechnolo- gien gegeben und der Zusammenhang mit visuellem Komfort und dem Wohlbefinden erläutert. Die Richtlinie 2010/31/EU des europäischen Parlaments und des Rates vom 19. Mai 2010 über die Gesamtenergieeffizienz von Gebäudenbesagt, dass neue Gebäudeab 2021 als Niedrigsten- ergiegebäudeerrichtet werden sollen. In diesem Zusammenhang spielt der elektrische Energiever- brauch fürBeleuchtung eine zunehmend wichtigere Rolle. Der Vortragende ist als Prokurist bei der Fa. Bartenbach LichtLabor in Aldrans fürForschung zuständig. Er ist in zahlreiche internationale Energieforschungsprojekte involviert, u.a. hat er im Auftrag des BMVIT Osterreich¨ im internationalen IEA- Projekt “Energy efficient electric Lighting for Buildings” vertreten und die Arbeitsgruppe “Zukünftige Lichttechnologien” geleitet (die Internationale Energieagentur IEA ist eine zwischenstaatliche Einrichtung zur Förderungenergiesparender Technologien und Aktivitäten), sowie im EU-Projekt “Commoncense” (Comfort monitoring for CEN standard EN15251 linked to EPBD) die österreichische Beteiligung geleitet (ein Projekt der Intelligent Energy Europe, kurz IEE). Hier wird u.a. die Rolle der Beleuchtung (Kunst- und Tageslicht) fürden Energieverbrauch von Gebäudenuntersucht.

32 Tue, 15:20 Smart Lighting for Smart Citizens - Mehr Licht !? und innovative Beleuchtungskonzepte f¨urSmart Cities. Mathias Schaﬀer1 1Energie Steiermark, Graz, Austria

Die Energie Steiermark beschäftigtsich seit 2010 systematisch mit dem Thema “Innovation” bzw. Innovationsmanagement. Zielsetzung der Innovation ist dabei primärdie Entwicklung neuer Ideen zu marktfähigenProdukten und Energie-Dienstleistungen im Kontext zum beginnenden Wandel der Energiesysteme sowie des gesellschaftlichen Wertewandels. Neben der aktuellen, kun- denorientierten Entwicklung von innovativen Produkten und Dienstleistungen u.a. auch fürden Bereich der Beleuchtung werden die Haupt-Innovationsthemen der Branche wie z.B. Smart Me- ter/Grid, dezentrale Erzeugung und Elektromobilitätals Teil großflächiger Modellversuche sog. “Smart Cities” demonstriert. Energie und deren Verwendung bzw. Anwendung unter Einsatz neuester und hocheffizienter Technologie ist auch in der ”Stadt der Zukunft” ein Schlüsselthema – wie leben und arbeiten wir im Jahr 2050, welche Energieformen und Technologien stehen uns zur Verfügung?Eine (mögliche) Projektion der “Vision 2050” einer “Smart City” fürdas Thema “Licht”...

Tue, 15:50 Schlussworte Norbert Pillmayr1

1KELAG - K¨arntnerElektrizit¨ats-Aktiengesellschaft, Klagenfurt, Austria

33 34 4 Nuclear and Particle Physics (FAKT) Tue: HS 15.02; Thu, Fri: HS 15.03

Nuclear and Particle Physics Kern- und Teilchenphysik Daniel Grumiller, [email protected]

Tuesday, 18th September 2012, HS 15.02 13:30 - 16:00 Time Presenter Title Gravity Resonance Spectroscopy 13:30 - 13:50 Tobias Jenke within the qBounce experiments 13:50 - 14:10 Johann Marton New experiments on light kaonic atoms Comparison of the yields in kaonic 14:10 - 14:22 Barbara Wünschek helium-3 and helium-4 Measuring the hyperfine-splitting of 14:22 - 14:34 Clemens Sauerzopf Antihydrogen An apparatus for the production of a 14:34 - 14:46 Martin Diermaier mono atomic hydrogen beam AMS Measurements of Supernova- 14:46 - 14:58 Jenny Feige Produced Radionuclides in Deep-Sea Sediment Cores AMS detection of 10Be with a sili- 14:58 - 15:10 Edith Schmidt con nitride foil stack: higher efficiency, lower background The age of olfactory bulb neurons in humans: an application of dating mi- 15:10 - 15:22 Jakob Liebl crogram DNA samples with the C14 bomb peak

35 Thursday, 20th September 2012, HS 15.03 09:00 - 11:00 Time Presenter Title Recent results from the CMS experi- 09:00 - 09:20 Wolfgang Adam ment at the LHC The CMS simplified models results in- 09:20 - 09:32 Wolfgang Waltenberger terpreted for your favorite theory – a how-to Search for Supersymmetry in final 09:32 - 09:44 Robert Schöfbeck states with b-jets and leptons with the CMS experiment Measurement of Upsilon(nS) Polariza- 09:44 - 09:56 Ilse Krätschmer tion with CMS Recent Heavy Flavour Results at the 09:56 - 10:08 Patrick Jussel ATLAS Experiment at the LHC Search for rare Bs → µ + µ− decay 10:08 - 10:20 Anna Usanova with the ATLAS detector Measurement of charged-particle mul- 10:20 - 10:32 Wolfgang Lukas tiplicities with the ATLAS detector at the LHC 10:32 - 10:52 Christoph Schwanda Physics at the Belle II experiment Study of B0s → J/ψK + K− decays 10:52 - 11:04 Felicitas Thorne at Belle experiment 11:04 - 11:30 Coffee break

Thursday, 20th September 2012, HS 15.03 14:30 - 15:30 Time Presenter Title Holographic dilepton and prompt pho- 14:30 - 14:42 Stefan Stricker ton production in a thermalizing plasma Status of the g-2 of the muon: trou- 14:42 - 14:54 Richard Williams ble for the standard model or theorists overconfidence Electron-Positron Pair Production in 14:54 - 15:06 Christian Kohlfürst Structured Pulses of Electric Fields Zwei- und Dreipunktfunktionen zwei- 15:06 - 15:18 Markus Huber dimensionaler Yang-Mills-Theorie in Landau Eichung Polyakov-Loops and the QCD Phase 15:18 - 15:30 Tina Herbst Structure 15:30 - 15:50 Coffee break

36 Thursday, 20th September 2012, HS 15.03 15:50 - 18:00 Time Presenter Title Consequences of an Infrared Divergent 15:50 - 16:02 Mario Mitter Quark 4-Point Function Renormalization in Functional Ap- 16:02 - 16:14 Valentin Mader proaches 16:14 - 16:26 Andreas Windisch What is (not) a Glueball? The Role of the Quark-Gluon Vertex 16:26 - 16:38 Markus Hopfer Function in the QCD Phase Transition Properties of the Delta and Omega 16:38 - 16:58 Reinhard Alkofer Baryons from QCD Bound State Equa- tions The sigma meson in a covariant Dyson- 16:58 - 17:10 Matthias Blatnik Schwinger - Bethe-Salpeter approach Nucleon Compton scattering in the 17:10 - 17:22 Gernot Eichmann Dyson-Schwinger approach Matrix Models as uniﬁed models of 17:22 - 17:34 Harold Steinacker fundamental interactions

Friday, 21st September 2012, HS 15.03 09:00 - 11:00 Time Presenter Title Producing a new in-house C-14 stan- 09:00 - 09:12 Thomas Wieninger dard by irradiating graphite A multi-anode ionisation chamber for 09:12 - 09:24 Josef Buchriegler AMS at VERA 09:24 - 09:44 Gertrud Konrad Status Report on PERC Ein Neutronenspinresonator zur 09:44 - 09:56 Christoph Gösselsberger Erzeugung Wellenlängen-selektierter Neutronenpulse 09:56 - 10:08 Xiangzun Wang Magnetic Field System of PERC Calibration of the ATLAS electromag- 10:08 - 10:20 Florian Teischinger netic calorimeter at the per mill level The Integrated Simulation Framework 10:20 - 10:32 Elmar Ritsch – A novel Detector Simulation Ap- proach in the ATLAS Experiment Radiation-hard silicon sensors for the 10:32 - 10:44 Bernhard Lutzer CMS tracker upgrade Development and Production of Sili- 10:44 - 10:56 Edwin Frühwirth con Particle Detectors in Austria 11:00 - 11:30 Coffee break

37 Friday, 21st September 2012, HS 15.03 11:30 - 13:30 Time Presenter Title Monitoring of the radiation induced ef- 11:30 - 11:42 Wolfgang Treberer-Treberspurg fects of the CMS Tracker Belle II Silicon Vertex Detector: Me- 11:42 - 11:54 Immanuel Gfall chanics Belle II Silicon Vertex Detector: Cool- 11:54 - 12:06 Annekathrin Frankenberger ing Low-momentum track reconstruction 12:06 - 12:18 Jakob Lettenbichler in the vertex detector of Belle II Forward Tracking in a Linear Collider 12:18 - 12:30 Winfried Mitaroﬀ Detector Computational Uncertainties in Public 12:30 - 12:42 Sebastian Frank BR(B → Xsγ) Codes Recovery Time and Double Hit Reso- 12:42 - 12:54 Lukas Gruber lution Measurements of SiPMs Using a Double Pulsed Laser

38 Tue, 13:30 - 16:00, HS 15.02

Tue, 13:30 Gravity Resonance Spectroscopy within the qBounce experiments Tobias Jenke1 1Technische Universit¨at Wien, Stadionallee 2, 1020 Wien, Austria

Newton’s Inverse Square Law of Gravity may be tested at micron distances deeply into the theoretically interesting regime by quantum interference with ultra-cold neutrons. Our newly developed method is based on a resonance spectroscopy technique related to Rabi spectroscopy, which has been adapted to gravitationally bound quantum systems: By coupling such a quantum system to mechanical vibrations, we observe resonant transitions, devoid of electromagnetic interaction. As Newtonian gravity and hypothetical Fifth Forces evolve with diﬀerent phase information, the experiment has the potential to test the equivalence principle and Newton’s gravity law at the micron scale. This experiment can therefore test speculations on large extra dimensions of sub- millimetre size of space-time or the origin of the cosmological constant in the universe, where eﬀects are predicted in the interesting range of this experiment and might give a signal in an improved setup.

Tue, 13:50 New experiments on light kaonic atoms Johann Marton1, The LEANNIS network2, The SIDDHARTA Collaboration3

1Osterreichische¨ Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria 2http://www.oeaw.ac.at/smi/research/topics/strong-interaction/leannis/ 3http://www.lnf.infn.it/esperimenti/siddharta/

The antikaon interaction on nucleons and nuclei in the low-energy regime is neither simple nor well understood. Even the kaonic hydrogen and kaonic deuterium cases are complicated due to sub-threshold resonances – most prominent is the Lambda(1405) resonance of still heavily debated nature. New experimental studies via x-ray spectroscopy of the lightest kaonic atomic systems (kaonic hydrogen and helium isotopes) have successfully performed by the SIDDHARTA Collabo- ration at LNF (Frascati, Italy) recently. Consequently new precision data on the strong interaction observables were delivered giving important impact for the theory. The talk will give an overview of the progress and present status of experimental studies and will provide an outlook to future perspectives in this fascinating research ﬁeld.

39 Tue, 14:10 Comparison of the yields in kaonic helium-3 and helium-4 Barbara W¨unschek1, Tomoichi Ishiwatari1, Eberhard Widmann1, Johann Zmeskal1, Michael Cargnelli1, Johann Marton1

1Osterreichische¨ Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria

Kaonic helium is an exotic atom where a kaon replaces a shell electron, well suited for the study of the strong interaction at low energies. The strong interaction between the kaon and the nucleus affects the low-lying atomic states in the kaonic helium atom by causing a shift compared to its purely electromagnetic value. This shift can be measured with spectroscopic tools, which was recently performed by the SIDDHARTA experiment. Via a measurement of the X-ray transitions to the 2p level, the X-ray transitions in kaonic helium-3 and helium-4 (at different densities) were measured with a complex SDD detector system. With the data set of these measurements, the X-ray yields (i.e. the net production of characteristic X-rays) of the kaonic helium gases have been determined for the first time. The absolute yields were obtained with inputs from a Monte Carlo simulation. Since the previous measurements on the kaonic helium X-ray transitions solely used liquid helium targets, these results give crucial information on theoretical calculations of the den- sitydependence of the yields. The evaluation procedure and the results are going to be presented in detail.

Tue, 14:22 Measuring the hyperfine-splitting of Antihydrogen Clemens Sauerzopf1, Martin Diermaier1, Silke Federmann1, ChloéMalbrunot1, Oswald Massiczek1, Barbara Wünschek1, Johann Zmeskal1, Eberhard Widmann1, The ASACUSA Collaboration2

1Osterreichische¨ Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria 2http://asacusa.web.cern.ch/ASACUSA/

In our current understanding of the standard model of particle physics, the CPT (charge, parity, time) symmetry states that the laws of physics do not change under inversion. The ASACUSA Collaboration intends to test this fundamental property of the model by measuring a hyperfine transition in Antihydrogen, the antimatter pendant to ordinary matter Hydrogen, using a Rabi like experimental setup. Compared to the number of cosmic particles and background radiation from Antiproton annihilation a proper Antihydrogen event is quite rare. To accomplish a good measurement we need a fine discrimination between proper events and background hits. To this purpose, our counting system consists of a veto detector to single out upstream annihilations, a central segmented detector, and a hodoscope which provides a good detection probability for decay pions. In this talk I will discuss the development of the Antihydrogen counter and present first preliminary results of measurements at the CERN Antiproton Decelerator (AD).

40 Tue, 14:34 An apparatus for the production of a mono atomic hydrogen beam Martin Diermaier1, Oswald Massiczek1, Eberhard Widmann1, Johann Zmeskal1

1Osterreichische¨ Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria

CPT (charge, parity, time) symmetry plays a fundamental role in our understanding of physical laws – under the simultaneous inversion of charge, parity and time the physics law do not change. The CPT symmetry will be tested by the ASACUSA collaboration at the CERN facility. This test will be done in a Rabi like experiment with antihydrogen atoms, the antimatter pendant to normal hydrogen atoms. Since the creation of antihydrogen atoms is very complicated the whole setup has to be tested and calibrated with hydrogen. Therefore an atomic hydrogen beam apparatus has been setup, using a microwave discharge source for the production and a quadrupole mass spectrometer for the detection of the mono atomic hydrogen beam. In this talk the apparatus and ﬁrst test measurements will be discussed.

Tue, 14:46 AMS Measurements of Supernova-Produced Radionuclides in Deep-Sea Sediment Cores Jenny Feige1, Anton Wallner2, Stephan Winkler1, Silke Merchel3, Keith Fiﬁeld2, Gunther Korschinek4, Georg Rugel3, Robin Golser1

1University of Vienna, WähringerStrasse 17, 1090 Vienna, Austria 2Australian National University,Building No. 57, The Australian National University, Canberra, ACT 0200, Australia 3Helmholtz Institute Freiberg for Resource Technology, HalsbrückerStraße 34, 09599 Freiberg, Germany 4Technische UniversitätMünchen,James-Franck-Str. 1, 85748 Garching, Germany

Accelerator Mass Spectrometry (AMS) provides the highest sensitivity for measurements of long-lived radionuclides with half-lifes in the order of million years. We apply this method to search for live supernova (SN)-produced radionuclides on Earth. An indication to recent SN activity in our solar neighborhood is the existence of a thin, hot cavity in the local interstellar medium, embedding our solar system. This so called superbubble, the Local Bubble, was produced by multiple SN explosions, starting ∼14 Myr ago. Nuclides, which are synthesized in massive stars and during their explosions, are then entrained in the SN shell and may be transported to the solar system and thus into Earth archives, if such an event happens within a short distance. Two deep-sea sediment cores originating from the Indian Ocean have been selected to search for the SN-produced radionuclides 26Al, 53Mn, 60Fe and 244Pu in the time range of 2-3 Myr. We aim to measure these isotopes at different laboratories with high time resolution with the goal to confirm a previously found SN signal in a ferromanganese crust from the Pacific Ocean.

41 Tue, 14:58 AMS detection of 10Be with a silicon nitride foil stack: higher eﬃciency, lower background Edith Schmidt1, Peter Steier1, Josef Buchriegler1, Jenny Feige1, Martin Martschini1, Leonard Michlmayer1, Alfred Priller1, Anton Wallner1, Eva-Maria Wild1, Robin Golser1

1University of Vienna, W¨ahringerStrasse 17, 1090 Vienna, Austria

10Be, with a half-life of 1.39 Ma, is a long-lived, naturally occurring radioisotope with versatile applications. It is a cosmogenic nuclide, produced in the atmosphere and in-situ in surface rocks. 10Be therefore carries valuable signals for climate research [1,2] and also is the primary tool for exposure dating [3] in geology. Accelerator Mass Spectrometry (AMS) with its outstanding abundance sensitivity is the only technique capable of measuring 10Be at natural levels and separating it from abundant isobaric 10B. Based on extremely homogeneous silicon nitride foils, we have developed a new AMS-method to detect 10Be at the Vienna Environmental Research Accelerator (VERA). The new method has a signiﬁcantly higher overall eﬃciency, provides superior precision and is simpler to implement. For comparison, we also present the two other methods, which are available at VERA and commonly used at other facilities: absorption of 10B in a gas cell, and the use of a degrader foil followed by a magnetic separator. [1] RAISBECK et. al. (2006) 10Be evidence for the Matuyama-Brunhes geomagnetic reversal in the EPICA Dome C ice core. Nature 444, 82. [2] WILLENBRING, J.K., VON BLANCKENBURG, F. (2010) Long-term stability of global ero- sion rates and weathering during late-Cenozoic cooling. Nature 465, 211. [3] JOHN, C., GOSSE, F., PHILLIPS, M.(2001) Terrestrial in situ cosmogenic nuclides: theory and application. Quaternary Science Reviews 20, 1475.

Tue, 15:10 The age of olfactory bulb neurons in humans: an application of dating microgram DNA samples with the C14 bomb peak Jakob Liebl1,2,3, Peter Steier1, Olaf Bergmann4, Jonas Fris´en4, Kirsty Spalding4, Robin Golser1, Klaus Mair1, Alfred Priller1, Eva-Maria Wild1, Walter Kutschera1

1University of Vienna, W¨ahringerStrasse 17, 1090 Vienna, Austria 2MedAustron, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria 3Medizinische Universit¨atGraz, Auenbruggerplatz 32, 8036 Graz, Austria 4Karolinska Institutet, SE-171 77 Stockholm, Sweden

The determination of C14 levels in genomic DNA can be used to retrospectively establish the birth date of cells in the human body which was pioneered at the Karolinska Institute. Above- ground nuclear weapons testing between 1950 and 1963 doubled the atmospheric C14 content. After the Partial Nuclear Test Ban Treaty in 1963 the excess C14 decreased again by exchange of carbon dioxide between atmosphere, biosphere and the ocean. As a consequence all humans who lived in the second half of the 20th century have been labelled with this rapidly changing excess C14. During the last years the amount of carbon required for a C14 Accelerator Mass Spectrometry (AMS) measurement at the VERA Laboratory in Vienna was reduced to such an extent (mg to µg) that investigations of neurons of particularly interesting small sections of the human brain became possible. C14 measurements of < 5µg carbon DNA samples with an overall precision of 2.0 to 2.5% were achieved. This allowed to study neurogenesis in the human olfactory bulb [1], which turned out to take place primarily at birth with <1% of these neurons being exchanged at a later time. This identifies a fundamental difference in the plasticity of the human brain compared to other mammals. [1] O. Bergmann, J. Liebl, S. Bernard, K. Alkass, M.S.Y. Yeung, P. Steier, W. Kutschera, L. Johnson, M. Landén,H. Druid, K.L. Spalding, J. Frisén,“The Age of Olfactory Bulb Neurons in Humans”, Neuron 74, 634 (2012)

42 Thu, 09:00 - 11:00, HS 15.03

Thu, 09:00 Recent results from the CMS experiment at the LHC Wolfgang Adam1

1Institut f¨urHochenergiephysik, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The CMS experiment is in its third full year of data taking at the LHC, recording proton-proton collisions at a record centre-of-mass energy of 8 TeV. The total integrated luminosity is expected to clearly exceed the 5 fb−1 available for the analysis of 2011 data. CMS pursues a wide research programme with highlights ranging from the search for the Higgs boson and supersymmetric particles to precision measurements in top- and b-quark physics. An overview of the most signiﬁcant CMS results with emphasis on those obtained from the ﬁrst part of 2012 data will be presented.

Thu, 09:20 The CMS simpliﬁed models results interpreted for your favorite theory – a how-to Wolfgang Waltenberger1

1Institut f¨urHochenergiephysik, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The year 2011 was a fruitful one for the CMS teams that searched for physics beyond the standard model. The results of many analyses have been interpreted in the context of simplified models, i.e. effective Lagrangians which introduce only a minimal set of hypothetical, new particles. In this talk, a description and summary of these simplified models results will be given. An application of these results that can be performed by physicists outside the CMS collaboration will be presented.

Thu, 09:32 Search for Supersymmetry in ﬁnal states with b-jets and leptons with the CMS experiment Robert Sch¨ofbeck1 1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

A large class of supersymmetric models predict an enhanced production of 3rd generation fermions at the LHC. In particular, the supersymmetric partners of bottom and top quarks could be among the lightest charged supersymmetric particles and would give rise to jets originating from the fragmentation of b-quarks. Results from searches for Supersymmetry with the CMS experiment using ﬁnal states including with b-jets are reported based on proton-proton collision data at a centre-of-mass energy of 7 TeV and 8TeV. In particular, a searches for events with (b-)jets, isolated leptons and high missing transverse energy are presented. The results are also interpreted in the framework of “simpliﬁed models”.

43 Thu, 09:44 Measurement of Upsilon(nS) Polarization with CMS Ilse Kr¨atschmer1 1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

An introduction to the measurements of quarkonia polarization with the CMS detector at the LHC is presented. The measurement is based on the angular distributions of decays into muons. ˜ The polarization parameters λθ, λφ and λθφ as well as a frame invariant quantity λ are determined. This frame-invariant quantity provides an intrinsic test of the reliability of the whole analysis chain and gives supplementary physical information. Results for the Y(1S), Y(2S) and Y(3S) mesons using data collected in 2012 are shown.

Thu, 09:56 Recent Heavy Flavour Results at the ATLAS Experiment at the LHC Patrick Jussel1 1University of Innsbruck, Technikerstrasse 15, 6020 Innsbruck , Austria

In 2011 data corresponding to an integrated luminosity of more than 5 fb−1 has been collected by the ATLAS experiment [1] at the Large Hadron Collider at CERN. The heavy ﬂavour program covers the measurement of CP violation, the discovery of new B hadrons and very rare B meson decays. In this presentation recent results of the ATLAS heavy ﬂavour physics program will be presented.

[1] The ATLAS Collaboration; The ATLAS Experiment at the CERN Large Hadron Collider; JINST 3 (2008) S08003

Thu, 10:08 Search for rare Bs → µ + µ− decay with the ATLAS detector Anna Usanova1 1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria

A blind analysis searching for the decay Bs → µ + µ− has been performed [1] using proton- proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC in 2011. The Bs → µ+µ− branching fraction is measured with respect to the reference decay B± → J/ψK±. The details of this analysis and the most recent results on the measurement of the branching fraction BR(Bs → µ + µ−) will be presented.

[1] The ATLAS Collaboration; Search for the decay B0s → µ + µ− with the ATLAS detector; to be published

44 Thu, 10:20 Measurement of charged-particle multiplicities with the ATLAS detector at the LHC Wolfgang Lukas1, Emmerich Kneringer1, Andreas Salzburger2

1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria 2CERN, 1211 Geneva 23, Switzerland

Measurements of charged-particle distributions in particle collider experiments provide an essential insight into the understanding of soft QCD as well as high-pT phenomena, which are becoming increasingly important for high-energy physics at the LHC. The status of ongoing measurements√ of the charged-particle multiplicity in proton-proton interactions at the center-of-mass energy s = 8 TeV, depending on transverse momentum and pseudorapidity, and of the relationship between mean transverse momentum and charged-particle multiplicity, is presented for the ATLAS experiment. These measurements are compared to Monte Carlo models, particularly the Pythia6 and Pythia8 tunes. Finally the 8 TeV results are combined with previous measurements from 900 GeV to 7 TeV, in order to validate and improve the extrapolation of the central charged- particle multiplicity per event and unit of pseudorapidity for tracks with transverse momentum pT > 100 MeV and pT > 500 MeV.

Thu, 10:32 Physics at the Belle II experiment Christoph Schwanda1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The B factory at KEK in Japan is being upgraded to become a Super B factory: The new experiment, Belle II, will start data taking in the year 2015 and aims at increasing the B factory dataset by two orders of magnitude. This huge luminosity will allow to study B and tau decays with unprecedented precision and gain sensitivity to physics scenarios beyond the Standard Model of particle physics (so-called New Physics). We will present the planned measurements and give expected sensitivities in key observables. We will explain how diﬀerent New Physics models can be probed with the upgraded detector.

Thu, 10:52 Study of B0s → J/ψK + K− decays at Belle experiment Felicitas Thorne1, Christoph Schwanda1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The Belle experiment in Tsukuba (Japan) has collected a unique 121/fb dataset near the Y(5S) resonance, which allows to study B0s meson decays. We will report a study of B0s → J/ψK + K− decays using this sample. This includes the measurement of the absolute branching fractions for B0s → J/ψφ with φ → K + K− and B0s → J/ψK + K−, the search for the decay B0s → J/ψf 02(1525) with f 02(1525) → K + K− and the determination of the s-wave contribution in the φ mass range. The decay B0s → J/ψφ is an important mode for measuring the CP violating phase βs, which is particularly sensitive to physics beyond the Standard Model. This work is supported by the Austrian Science Fund (Grant Nr. P22742-N16).

45 Thu, 14:30 - 15:30, HS 15.03

Thu, 14:30 Holographic dilepton and prompt photon production in a thermalizing plasma Stefan Stricker1 1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria

We determine the out-of-equilibrium production rate of dileptons and prompt photons in strongly coupled N=4 Super Yang-Mills plasma using the AdS/CFT correspondence. Thermal- ization is achieved via the gravitational collapse of a thin shell of matter in anti-de-Sitter spacetime and the subsequent formation of a black hole, which we describe in a quasistatic approximation. Prior to thermalization, the spectral functions of dileptons and photons are observed to oscillate as a function of frequency, but the amplitudes of oscillations decrease when thermal equilibrium is approached.

Thu, 14:42 Status of the g-2 of the muon: trouble for the standard model or theorists’ overconﬁdence Richard Williams1, Christian Fischer2, Tobias G¨ocke2

1University of Graz, Universitätsplatz5, 8010 Graz, Austria 2UniversitätGiessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

A several year old discrepancy at the 2-3 sigma level between precision Standard Model com- putations of the muon’s magnetic moment and experimental measurement deﬁes theory. I quickly review the last measurements, the various contributions to the theory estimate that include a mind- boggling 5-loop QED calculation as well as high-order QCD and electroweak corrections, and concentrate especially on the hadronic contributions I will show how progress in the Dyson-Schwinger formulation of Chromodynamics provides a cross-check, extension and improvement over future lattice and existing quark model and eﬀective Lagrangian estimates, highlighting the strengths and weaknesses of the various approaches.

Thu, 14:54 Electron-Positron Pair Production in Structured Pulses of Electric Fields Christian Kohlf¨urst1, Florian Hebenstreit1, Reinhard Alkofer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

The non-perturbative electron-positron pair production (Schwinger effect) in time-dependent pulse-shaped electric fields is investigated. For pulses of experimental interest the employed quantum kinetic formalism reduces the equation for the electron (positron) density to a set of ordinary coupled differential equations of first order. The dynamical effect of electric fields with at least two different time scales within the pulse is studied. First results for an optimization of the particle density yield by pulse-shaping will be given.

46 Thu, 15:06 Zwei- und Dreipunktfunktionen zwei-dimensionaler Yang-Mills-Theorie in Landau Eichung Markus Huber1, Axel Maas2, Lorenz von Smekal1

1Technische Universit¨atDarmstadt, Schlossgartenstrasse 9, 64289 Darmstadt, Germany 2Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743 Jena, Germany

Gittersimulationen und nicht-perturbative Kontinuumsmethoden wie die funktionale Renor- mierungsgruppe und Dyson-Schwinger-Gleichungen haben unterschiedliche Stärken und Schwächen und ergänzeneinander sehr gut. Da auf dem Gitter niedrige Impulse in zwei und drei Dimen- sionen leichter als in vier Dimensionen erreicht werden können,werden Rechnungen auch damit durchgeführt.Dabei stellte sich heraus, dass das Verhalten in zwei Dimensionen qualitativ anders ist als in drei und vier Dimensionen. Hier präsentieren wir analytische und numerische Ergebnisse von Dyson-Schwinger-Gleichungen, die diesen Unterschied erklären.Eines der Hauptergebnisse ist die Sensibilitätder Ergebnisse auf den Bereich mittlerer Impulse, auf welchen Trunkierungen den meisten Einfluss haben. Um die Trunkierungsabhängigkeit zu verkleinern, lösenwir die Propagator- Gleichungen gemeinsam mit der Dyson-Schwinger-Gleichung des Geist-Gluon-Vertex.

Thu, 15:18 Polyakov-Loops and the QCD Phase Structure Tina K. Herbst1, Bernd-Jochen Schaefer1, Jan Martin Pawlowski2

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2Universit¨atHeidelberg, Philosophenweg 16, 69120 Heidelberg, Germany

We discuss the impact of fluctuations on the chiral and deconfinement phase transition of QCD within an effective model. Thermal and quantum fluctuations are included via the functional renor- malisation group. Special emphasis is put on the matter backcoupling to the gauge sector, which has a drastic influence on the phase structure.

Thu, 15:30 - 15:50: Coﬀee break

47 Thu, 15:50 - 18:00, HS 15.03

Thu, 15:50 Consequences of an Infrared Divergent Quark 4-Point Function Mario Mitter1, Reinhard Alkofer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Based on the idea that a conﬁning linear rising quark potential can be explained by a 1/k4 divergence in the quark 4-point function, we ﬁnd restrictions on the color tensor structure of this divergence. Furthermore, we investigate consequences on other Green functions.

Thu, 16:02 Renormalization in Functional Approaches Valentin Mader1, Reinhard Alkofer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

In Functional Approaches, correlation functions are calculated self-consistently. Back-coupling effects lead to drastic modification in the renormalization program in quantum field theories. Using the Dyson-Schwinger equations of Yang-Mills theory we investigate the influence of quadratic and logarithmic divergences on the solution process of such equations.

Thu, 16:14 What is (not) a Glueball? Andreas Windisch1, Markus Huber2, Reinhard Alkofer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2Technische Universit¨atDarmstadt, Schlossgartenstrasse 9, 64289 Darmstadt, Germany

We present a short review on what glueballs are and how they can be described theoretically. In particular we discuss a scalar glueball, which is described by the two-point function of the square of the Yang-Mills field strength tensor. The momentum-space operator corresponding to this correlator has been constructed such that dierent gluon-propagators in 2 and 4 dimensions can be plugged into the expression. While the gluon-propagators have been taken from non-perturbative studies, the correlator itself is of lowest order in the coupling. By analytic continuation we extend the solution to complex values of p2, the square of the external momentum. The structure of the correlator in the complex plane encodes important information of the propagating degree of freedom, such as its mass or whether it is a bound state or not. We perform this investigation numerically by applying a specifically developed procedure which involves Graphics Processing Units to carry out this computationally intensive task [1]. This tool allows us to investigate a variety of gluon propagators of dierent origin, without having to deal with the limitations present due to their complicated integral representations. The aim of this talk is to present not only the procedure used throughout the study, but also to stress what is not sufficient to get a glueball, restricting the ingredients of this highly interesting, experimentally hard-to-prove objects. [1] A. Windisch, R. Alkofer, G. Haase and M. Liebmann, arXiv:1205.0752 [hep-ph].

48 Thu, 16:26 The Role of the Quark-Gluon Vertex Function in the QCD Phase Transition Markus Hopfer1, Mario Mitter1, Bernd-Jochen Schaefer1, Reinhard Alkofer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

During the last years, intensive theoretical and experimental efforts towards a deeper understanding of the strong interactions between quarks and gluons, the fundamental fields in nature, have been made. In particular, the observed phenomena of confinement and dynamical mass generation were at the focus of many contemporary studies. Up to now, the emergence of these phenomena from the underlying fundamental theory, quantum chromodynamics (QCD), is not understood in detail. Moreover, the transition from the confined hadronic phase to the quark-gluon plasma phase induces a sudden change in the particle masses indicating a relation between these phenomena. As confinement and chiral symmetry breaking are intrinsic properties of the strong interaction in the infrared, they are not accessible by perturbation theory. By relating the Greens functions of the theory, the Dyson-Schwinger formalism offers a non-perturbative description of the dynamics including quantum fluctuations which are mandatory in the vicinity of phase transitions. The quark-gluon vertex is the central object in this context linking the quark with the Yang-Mills sector of the theory. Due to its complexity only models for this vertex are used up to now. The major focus is to replace these models by a detailed numerical investigation, including the relevant tensor structure and probing subsequently the phase diagram of QCD.

Thu, 16:38 Properties of the Delta and Omega Baryons from QCD Bound State Equations Reinhard Alkofer1, Helios Sanchis-Alepuz1, Richard Williams1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Based on rainbow-ladder truncated QCD bound state equations properties of the quark core of mesons and baryons are calculated from their respective Bethe-Salpeter and Poincare-covariant Faddeev amplitudes. Results on the spectrum and electromagnetic form factors of Delta/Omega baryons from light to heavy quarks are presented. To evaluate their dependence on the rainbow- ladder truncated, eﬀective interaction calculations employing two diﬀerent models have been performed.

Thu, 16:58 The sigma meson in a covariant Dyson-Schwinger - Bethe-Salpeter approach Matthias Blatnik1, Reinhard Alkofer1, Richard Williams1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

We study the f(600) or σ, the lowest scalar meson resonance, in the framework of a Dyson- Schwinger - Bethe-Salpeter approach which is based on the non-pertubative Green’s functions of QCD. The σ has exactly the same quantum numbers as the vacuum, and it plays an important role in dynamical chiral symmetry breaking and in nuclear physics. We investigate the σ starting with a qq¯ state and aim in particular to include the decay into and coupling to two pions. We will give results for the bare, i.e., qq¯ masses of the σ and the π and estimates for the σ mass and decay width.

49 Thu, 17:10 Nucleon Compton scattering in the Dyson-Schwinger approach Gernot Eichmann1 1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Compton scattering on the nucleon provides a unique tool to probe the nonperturbative structure of the nucleon. It allows access to a range of observables that are subject to studies at major experimental facilities, including: the nucleon’s generalized polarizabilities; two-photon contributions to form factors; nucleon structure functions and generalized parton distributions; and proton- antiproton annihilation processes. A nonperturbative approach for investigating such phenomena is given by the combination of QCD’s Dyson-Schwinger equations with covariant Bethe-Salpeter and Faddeev equations. The framework has been recently applied for describing nucleon and delta elastic and transition form factors, and its systematic extension to Compton scattering, pion elec- troproduction and nucleon-pion scattering has been outlined. I will discuss recent progress in this area and present ﬁrst results for the nucleon’s Compton scattering amplitude.

Thu, 17:22 Matrix Models as uniﬁed models of fundamental interactions Harold Steinacker1 1University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria

Matrix models have been proposed as a non-perturbative definition of string theory. Basic solutions and mechanisms are discussed for the so-called IKKT model. Space-time can arise as brane solution, while gauge fields arise from fluctuations around stacks of branes. This leads to a braneworld scenario, with many parallels but also differences to more conventional string theory constructions. A overview of recent progress and an outlook is given.

50 Fri, 09:00 - 11:00, HS 15.03

Fri, 09:00 Producing a new in-house C-14 standard by irradiating graphite Thomas Wieninger1, Klaus Mair1, Johannes Sterba2, Peter Steier1, Robin Golser1

1University of Vienna, W¨ahringerStrasse 17, 1090 Vienna, Austria 2Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

Accelerator mass spectrometry (AMS) always performs measurements relative to a standard, which significantly improves the precision. C-14 measurements need a chemical treatment to transform carbon into graphite, to be used in the popular Cs-sputter sources. A homogeneous bulk of several gram of graphite containing C-14 would allow to study the performance of the mass spectrometer independent of sample preparation chemistry. Unfortunately, this material is not available so far. The aim was to produce such a new in-house standard for the VERA facility (University of Vienna). We started from dead (p.e. no C-14) graphite powder and irradiated it with thermal neutrons at the TRIGA Mark II reactor from the Institute of Atomic and Subatomic Physics (TU Vienna). Via the C-13(n, gamma)C-14 reaction we produced a C-14 isotopic abundance in the natural range of ∼ 10−12. The challenge of this work was to deal with an inhomogeneous neutron flux and the low cross section for the mentioned above reaction, compared to the much more efficient N-14(n,p)C-14. The homogeneity of the produced material was successfully verified by measurements of small aliquots.

Fri, 09:12 A multi-anode ionisation chamber for AMS at VERA Josef Buchriegler1, Alfred Priller1, Oliver Forstner1, Martin Martschini1, Peter Steier1, Robin Golser1 1University of Vienna, W¨ahringerStrasse 17, 1090 Vienna, Austria

AMS (Accelerator Mass Spectrometry) is a technique to measure long-lived radionuclides with extreme abundance sensitivity below 1E-12. For sufficient isobar suppression at low energies (<1 MeV/amu) a high-resolution detector is required. Based on recent experimental results for the separation of 36Cl from 36S, a new gas ionisation chamber with a multi-anode design was built at VERA (Vienna Environmental Research Accelerator). It provides up to 8 energy loss signals for particle identification. In order to reduce electronic noise special low-capacitive conductors are used inside the gas volume; also the preamplifiers are mounted directly on the detector housing. The dimensions of the Frisch grid [1] and the distances between grid and electrodes were optimized both for short pulse rise times as well as minimum grid-inefficiency [2]. The flexibility of the design concerning the type of detector window, the configuration of anodes and the distances between grid and electrodes makes the detector also well suited for the measurement of heavy ions, e.g. 236U at low energies. Calculations and first experimental results of the detector’s performance will be presented. [1] Bunemann O., Cranshaw T. E., Harvey J. A., “Design of Grid Ionization Chambers”, Canadian Journal of Research 27A (1949) 191-206 [2] GöökA., “Investigation of the Frisch-grid inefficiency by means of wave-form digitization”, Dis- sertation, Orebro¨ Universitet

51 Fri, 09:24 Status Report on PERC Gertrud Konrad1, The PERC Collaboration2

1Technische Universit¨atWien, Stadionallee 2, 1020 Wien, Austria 2http://www.physi.uni-heidelberg.de/Forschung/ANP/PERC/collaboration.php

Important open questions of particle physics and cosmology can be addressed with precision measurements in neutron beta decay. Main emphasis lies on the search for evidence of possible extensions to the Standard Model and searches for new symmetry concepts. In general, these measurements are complementary to direct searches in high-energy physics. Observables in neutron decay are abundant: Besides the neutron lifetime, angular correlations involving the neutron spin as well as momenta and spins of the emitted particles are characterized by individual coefficients. These coefficients can be related to the underlying coupling strengths of the weak interaction, including yet unobserved ones. Each coefficient in turn relates to an underlying broken symmetry. With the new facility PERC several symmetry tests based on neutron decay data become accessible. PERC (Proton Electron Radiation Channel) is a novel source of neutron decay products: these are collected by a strong longitudinal magnetic field of 1.5 T directly from inside a neutron guide. This combination provides highest phase space density of decay products. A magnetic mir- ror of up to 6 T serves to perform precise cuts in phase space, reducing related systematic errors. Altogether, the sensitivity of neutron decay studies will be improved by one order of magnitude. The new beam station PERC is currently under development by an international collaboration and will be installed at the FRM II in Garching, Germany. Besides the physics motivation, the concept, sensitivity, applications, and status of PERC are presented in this talk.

Fri, 09:44 Ein Neutronenspinresonator zur Erzeugung Wellenl¨angen-selektierterNeutronenpulse Christoph G¨osselsberger1, Gerald Badurek1, Erwin Jericha1

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

Im Rahmen dieses Beitrags stellen wir die erstmalige Entwicklung eines Wanderwellen-Neutronen- spinresonators zur Erzeugung nahezu beliebig geformter wellenlängenselektierter,polarisierter Neu- tronenpulse vor. Das Grundprinzip dafürist die räumliche magnetische Spinresonanz. Dabei werden die polarisierten Neutronen einem räumlich abwechselnden magnetischen Feld ausgesetzt, welches normal zur Polarisationsrichtung angelegt ist. Die Frequenz dieses alternierenden Mag- netfeldes ist im Bezugssystem eines einzelnen Neutrons jeweils von dessen Geschwindigkeit und der räumlichen Periode des Resonators abhängig. Sofern diese Frequenz mit der Larmorfrequenz der Neutronen übereinstimmt, welche durch das orthogonal angelegte statische Führungsfeld(Se- lektorfeld) bestimmt wird, findet ein Pi-Spinflip statt. Durch eine geeignete Justierung dieses Selektorfeldes kann somit eine bestimmte Wellenlängeselektiert werden. Bei der Neuentwick- lung wird ein sogenannter Wanderwellenmodus realisiert, bei dem ein “wanderndes” Magnetfeld, die zu erzeugenden Neutronenpulse durch den Resonator begleitet. Bei dieser Umsetzung er- scheinen um 2 Größenordnungen kürzerePulszeiten als bei einem traditionellen Resonator re- alisierbar. Der Aufbau aus Einzelelementen hat den wesentlichen Vorteil, dass die erzeugten Magnetfelder beliebig geformt und somit fürden Betrieb ungewollte Nebenmaxima in den selek- tierten Wellenlängenspektren eliminiert werden können.Außerdem könnendurch bloßes Einstellen der Strömesowohl die Wellenlängenverteilung als auch die Zeitstruktur nahezu beliebig justiert werden. Wir stellen hier sowohl die Designstudie als auch erste recht vielversprechende Mess- Resultate zweier Resonator-Prototypen vor und gehen auf mögliche zukünftigeAnwendungen ein (Strahlpräparation bei PERC, neuartiges 3-Achsen-Spektrometer, Erzeugung von maßgeschnei- derten Neutronenpulsen an der ESS).

52 Fri, 09:56 Magnetic Field System of PERC Xiangzun Wang1

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

The beam station PERC (Proton Electron Radiation Channel) is a new kind of spectrometer for neutron beta decay experiments, aiming to achieve precise measurements of energy spectra of electrons and protons (e-/p+) from free neutron decay, as well as various angular correlation coefficients that represent the properties of the weak and strong interactions. The main instrument of PERC provides a static magnetic field supported by a series of superconducting magnets, to col- lect and guide the charged decay e-/p+ particles from the decay to the detection area. To obtain high efficiencies and suppressed error levels, the strengths of the magnetic field have a functional distribution, with which the e-/p+ can be selected and defined due to their emission angles. In order to realize precise measurements, the decay e-/p+ are required to be transported with distortion of the observables below 10−4. Hence the functional magnetic fields must be well defined and homogeneous. To fulfil the requirements of systematics and physics, the magnet system of PERC is delicately designed with a dromedary geometry. The properties of the magnetic fields, the e-/p+ behaviors and the systematic effects are well studied in the simulations. Additionally, the practical and experimental factors are considered in the design of PERC, including the manufacture requirements, the tolerances of the field functions due to external influences, the properties of superconducting wire, and the magnetic forces and torques on the components.

Fri, 10:08 Calibration of the ATLAS electromagnetic calorimeter at the per mill level Florian Teischinger1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria

ATLAS is one of the experiments built to explore new physics at the TeV with proton-proton collisions at the Large Hadron Collider. The ATLAS experiment will brieﬂy described with emphasis on the ATLAS Liquid Argon electromagnetic calorimeter, this talk will concentrate on the performance and calibration of the electron reconstruction during the 2011 and 2012 data taking periods. Over the past years a calibration method for the energy scale of the liquid argon calorimeter using the distribution of the ratio of the electron energy measured by the calorimeter itself and the momentum measured by the Inner Tracking detector was developed. Results of this powerful calibration method using electrons from W and Z decays and combining the calorimetry and tracking information, will be presented. It will be shown how scale factors in ﬁne pseudo-rapidity bins can be extracted with a precision at the per mill level. These results will be compared to other calibration methods used in ATLAS . It will be demonstrated how the linearity of the response of the electromagnetic calorimeter can be measured in situ and how the passive material in front of the calorimeter can be estimated. Finally, the impact of this precise calibration of the electromagnetic calorimeter on selected physics measurements will be presented.

53 Fri, 10:20 The Integrated Simulation Framework – A novel Detector Simulation Approach in the ATLAS Experiment Elmar Ritsch1, Anna Usanova1, Peter Sherwood2, Francisca Garay Walls3, Andreas Schaelicke3, Andreas Salzburger4, Robert Duane Harrington Jr3, Julia Fischer5, Michael Duehrssen-Debling4

1University of Innsbruck, Technikerstraße 15, 6020 Innsbruck , Austria 2University College London, Gower Street, London WC1E 6BT, UK 3The University of Edinburgh, Mayﬁeld Road, Edinburgh EH9 3JZ, UK 4CERN, 1211 Geneva 23, Switzerland 5Bergische Universit¨atWuppertal, Gaußstrasse 20, 42119 Wuppertal, Germany

With the increasing amount of delivered luminosity by the Large Hadron Collider (LHC) at CERN, the demand for Monte Carlo simulated data grows accordingly. Given the computing resources of the ATLAS experiment this introduces strict requirements on detector simulation which is, in general, a very CPU intensive task. The Integrated Simulation Framework (ISF) is a completely new approach in optimizing ATLAS detector simulation given the need for high quality physics analyses on one side and restrictions on computing resources on the other. ISF builds a framework that allows to mix diﬀerent simulation engines on a particle level for the same event. By doing so, a gain of simulation time per event can be achieved if particles which are less relevant for subsequent analysis are e.g. done using fast simulation approaches. ISF combines the existing simulation engines used in ATLAS, which contain the Geant4 toolkit, a fast parameterized calorimeter simulation and a fast track simulation. This talk will discuss fundamental concepts, occurred problems that were solved during the design process of this framework along with ﬁrst results obtained using the new ISF prototype in ATLAS.

Fri, 10:32 Radiation-hard silicon sensors for the CMS tracker upgrade Bernhard Lutzer1 1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The Compact Muon Solenoid (CMS) experiment at the LHC at CERN is currently in operation and delivering promising and outstanding results. This particle detector experiment consists out of different types of detectors of which the Tracker is a very important one. It is made out of silicon-based strip detectors which perform very well at the moment. But due to the radiation damage imposed on these detectors, caused by the high fluences in the near-to-interaction-point region these silicon strip detectors will loose their detection ability with time and need to be eventually replaced by new a new tracker. Also the upgraded LHC which is planned to be in operation in 2020 will deliver a higher luminosity which requires very radiation-hard materials for the new detectors. Therefore a campaign is undergoing to determine which material is the most suitable for such challenging experimental conditions. Different materials for the wafer with different thick- nesses are characterized with test-structures and then irradiated with protons at Karlsruhe or with neutrons at TRIGA-reactors in Ljubljana or Vienna to simulate the conditions after several years of operation in the detector. These studies which are presented in this talk are conducted at HEPHY Vienna and will support the decision for the material used for building the upgraded CMS tracker.

54 Fri, 10:44 Development and Production of Silicon Particle Detectors in Austria Edwin Fr¨uhwirth1 1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

In particle physics experiments such as the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) at CERN large numbers of silicon based strip sensors are needed. These sensors are able to precisely detect particles generated in high energy proton-proton collisions and therefore allow reconstructing particle tracks. So far only a few vendors were capable of producing silicon strip sensors with the quality needed in particle physics experiments. Together with an Austrian-based semiconductor manufacturer the Institute of High Energy Physics (HEPHY) (of the Austrian Academy of Sciences) developed such sensors. This talk presents the development, production and electrical characterization of the first silicon strip sensors produced in Austria. The results from the first measurements presented in this talk demonstrate the good quality of the newly developed sensors and offer the possibility to establish the Austrian-based semiconductor manufacturer as a high quality vendor for particle physics detectors.

Fri, 11:00 - 11:30: Coﬀee break

55 Fri, 11:30 - 13:30, HS 15.03

Fri, 11:30 Monitoring of the radiation induced eﬀects of the CMS Tracker Wolfgang Treberer-Treberspurg1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The tracker of the CMS experiment at the LHC presents the largest silicon device ever built. Although its functionality is addressed to particle physics it also presents a unique opportunity to study well documented radiation damage eﬀects under very speciﬁc circumstances. During their lifetime the silicon modules have to withstand up to E15 traversing particles per cm2. However, the silicon sensor characteristic changes while ionizing radiation is damaging the crystal lattice. Each of the 15148 modules is featured with a detector control unit, recording amongst other things every single temperature, dark current and voltage value. Periodically dedicated runs are performed to determine the depletion voltage of each module. The dark current and its annealing behaviour in respect to temperature are measured as soon as the modules are turned on. All these data are used in simulations to expand existing models and deliver predictions concerning the tracker performance in the same time. The talk will present recent results, which have been considered in future constructions of the tracker, especially concerning cooling.

Fri, 11:42 Belle II Silicon Vertex Detector: Mechanics Immanuel Gfall1, Thomas Bergauer1, Annekathrin Frankenberger1, Markus Friedl1, Christian Irmler1, Manfred Valentan1, Paul Doljeschi1, Dusko Smiljic1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The Belle experiment at KEK in Tsukuba, Japan and its precision measurements have led to the justiﬁcation of the Nobel Prize earned by Kobayashi and Maskawa in 2008. In June 2010, the machine was brought to a halt for a promising future, namely an upgrade to Belle II which will be completed until 2015. By this time all important components are to be exchanged for an unprecedented performance boost of the accelerator (KEKB) and the Belle Detector. With this upgrade, KEKB will become SuperKEKB and beat its own luminosity world record (2.11 × 1034cm−2s−1) by a factor of 40. The core of the Belle II Experiment is composed of a DEPFET Pixel Detec- tor, which is surrounded by the Silicon Vertex Detector (SVD). The SVD is located close to the beam pipe to allow high precision vertex reconstruction. The proximity to the beam pipe and the high beam currents result in a very high level of background radiation for the SVD that both, the electronics and the mechanics have to cope with. The Origami sensor design was developed to provide a fast readout system at a very good signal to noise ratio. This design comes with a great performance increase that is able to fulﬁll with the new Belle II requirements. Nevertheless it is important to implement a light and yet stable mechanical construction that can withstand the radiation and temperature conditions without compromising the detector capabilities.

56 Fri, 11:54 Belle II Silicon Vertex Detector: Cooling Annekathrin Frankenberger1, Markus Friedl1, Thomas Bergauer1, Immanuel Gfall1, Manfred Valentan1, Christian Irmler1, Paul Doljeschi1, Dusko Smiljic1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

At the KEK, the High Energy Accelerator Research Organization in Tsukuba, Japan, currently the B-Factory KEKB and its experiment, the Belle detector get upgraded, aiming a higher luminosity. The improved Super B-Factory will reach a luminosity of 8 × 1035cm−2s−1 which is 40 times higher than the previous luminosity world record achieved there. For precise decay vertex measurements, a new silicon vertex detector (SVD) is required. The newly designed Belle II SVD comes along with a modern cooling system. The new Belle II SVD with its new “Origami” readout scheme requires an efficient cooling system for thermal control of the front-end electronics inside the detector volume. One of the most important figures of merit for vertex detectors is the amount of material seen by particles traversing the detector, therefore the material budget has to be kept as low as possible. To minimize the material budget, an evaporative CO2 cooling system has been chosen. CO2 provides excellent thermo-dynamical properties regarding its high heat transfer capability of evaporating CO2. This leads to a much smaller tube diameter and therefore lower mass inside the detectors active volume, compared to using fluorocarbons like conventional cooling systems do. The 2PACL (Two-Phase Accumulator Controlled Loop) developed at Nikhef provides a stable and easily controllable detector cooling system, completely fulfilling the experiments requirements. Integrating the cooling system into the heart of the Belle II detector is difficult and investigations are ongoing to meet the required material budget and space constraints.

Fri, 12:06 Low-momentum track reconstruction in the vertex detector of Belle II Jakob Lettenbichler1, Rudolf Fr¨uhwirth1, Moritz Nadler1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The vertex detector of the Belle II experiment will consist of two pixel layers (PXD) and four double-sided strip layers (SVD). While tracks with a transverse momentum above ∼ 100 GeV/c are seen in the Central Drift Chamber (CDC), tracks with lower transverse momentum, which are important in certain physics channels, have to be reconstructed in PXD and SVD only. Online track reconstruction, required for data reduction in the PXD, is even more difficult, as only the four SVD layers can be used. We present the strategy for low-momentum track finding in the SVD and SVD/PXD system. It is based on a cellular automaton, which is preceded by several filter stages designed to reduce the combinatorics. The subsequent track fit is performed using the GENFIT toolbox, which has been adapted to the specific features of low-momentum pions and their interaction with the detector material. We present results from simulated data, including background from the detector and the accelerator.

57 Fri, 12:18 Forward Tracking in a Linear Collider Detector Winfried Mitaroﬀ1, Robin Glattauer1, Rudolf Fr¨uhwirth1

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria

The International Large Detector (ILD) is one of two approved experiments at ILC, the global project for a future linear e-e+ collider with center-of-mass energy up to 1 TeV. A modified ver- sion is under study for CLIC, an alternative project for e-e+ collisions up to 3 TeV. The forward tracking part of ILD (FTD) consists of silicon pixel and micro-strip disks between beam tube and central TPC. Precise track reconstruction in these regions relies on an efficient track search. For processing the measurements of FTD within ILD’s software framework, we have developed a new and powerful stand-alone forward track search, based on 3 steps: a Cellular Automaton, a Kalman Filter, and a Hopfield Neural Network. We present this package, its methods and merits.

Fri, 12:30

Computational Uncertainties in Public BR(B → Xsγ) Codes Sebastian Frank1, Sabine Kraml2, Nazila Mahmoudi3,4, Shibi Rajagopalan2

1Austrian Academy of Sciences, Nikolsdorfer Gasse 18, 1050 Vienna, Austria 2LPSC Grenoble 53, rue des Martyrs 38026 Grenoble, France 3Laboratoire de Physique Corpusculaire Clermont-Ferrand, Campus des Czeaux 24, avenue des Landais BP 80026 63171 Aubire Cedex, France 4CERN, Oﬃce Building 53, 1211 Geneva 23, Switzerland

The branching ratio BR(B → Xsγ) is a sensitive probe for physics beyond the SM and thus an important constraint for parameter fits of SUSY models. It is therefore highly important to have a good assessment of theoretical and computational uncertainties, including the differences in the implementations and/or approximations used in public computational tools. We perform a detailed comparison of the various public BR(B → Xsγ) codes, evaluating the differences of the SM and MSSM results and their dependence on relevant parameters. The impact on SUSY fits is demonstrated via a global Bayesian analysis using Markov Chain Monte Carlo (MCMC) techniques.

58 Fri, 12:42 Recovery Time and Double Hit Resolution Measurements of SiPMs Using a Double Pulsed Laser Lukas Gruber1, Stefan Brunner1, Catalina Curceanu2, Johann Marton1, Antonio Romero Vidal3, Alessandro Scordo2, Ken Suzuki1, Oton Vazquez Doce4

1Osterreichische¨ Akademie der Wissenschaften, Boltzmanngasse 3, 1090 Vienna, Austria 2NFN - LNF, Via E. Fermi 40, 00044 Frascati (Roma), Italy 3Universidade de Santiago de Compostela, Ra Xos Mara Surez Nez, 15782 Santiago de Compostela, Spain 4Technische Universit¨atM¨unchen,James-Franck-Str. 1, 85748 Garching, Germany

The so-called Silicon Photomultiplier (SiPM) is a relatively novel type of semiconductor photo detector which consists of multiple pixels of Avalanche Photodiodes (APDs) working in Geiger- mode. One of the important parameters of photo sensors is the performance in high rate environments. For experiments like AMADEUS within the KLOE detector at LNF, where the detector system will be exposed to a very high rate shortly after the e+/e- injection, an overall rate capability is required. A charged kaon decay-mode tagging to distinguish K+ and K- is also very crucial to suppress the background. Therefore, a good double hit resolution is required. In order to characterize the rate capability and the double hit resolution, we performed an experimental study to determine the cell recovery time for various SiPMs of different vendors. The measurements are performed using a blue (407 nm) pulsed laser with 25 ps pulse width. We evaluated the recovery time constant by measuring the sensor response to two consecutive laser pulses, with a varying relative time difference of a few ns up to a few 100 ns, with a waveform digitizer (CAEN V1742, 5 GHz sampling). The two pulses are generated by splitting the laser signal, delaying one of the signals and merging again. The delay of the second pulse is done by coupling the light into optical fibers of different length (1 m to 200 m). The influence of the overvoltage on the recovery time is also studied.

59 60 5 Physics Teachers (LHS) HS 15.02

Physics in School Physik und Schule Leopold Mathelitsch, [email protected]

Wednesday, 19th September 2012, HS 15.02 14:30 - 15:00 Time Presenter Title 14:30 - 15:00 Mario M¨uller Mikrokraftwerke

Wednesday, 19th September 2012, HS 15.02 15:00 - 16:15 Sch¨ulerInnenstellen vor Presenter Title Die Teslaspule in Theorie und Experi- Stefan Mazuheli menten Nadine Schmalzer Materiewelleninterferometrie Halbleiter und Charakterisierung von Thomas Kamencek Halbleiternanostrukturen Nanobeschichtungen – Nanotechnolo- Thomas M¨ulleder gie in Theorie und Praxis Physikolympiade 2012 International Young Physicists’ Tournament 2012

Wednesday, 19th September 2012, HS 15.02 16:15 - 17:00 16:15 - 16:30 Victor Franz Hess Prize 16:30 - 17:00 Fachausschuss “Physik und Schule”

61 62 6 Acoustics (AKU) LS 15.02

Acoustics Akustik Holger Waubke, [email protected]

Thursday, 20th September 2012, LS 15.02 10:00 - 11:00 Time Presenter Title David Pirró 10:00 - 10:20 Alexander Wankhammer Acoustic Interface for Tremor Analysis Quellbreite von frontalen Phantom- 10:20 - 10:40 Matthias Frank schallquellen: Wahrnehmung, Mes- sung und Modellierung Einfache, auf Kammfilter beruhende 10:40 - 11:00 Franz Zotter Phantomschallquellenaufweitung 11:00 - 11:30 Coffee break

Thursday, 20th September 2012, LS 15.02 14:30 - 15:50 Gaussian Closure Technik fürdie Bes- 14:30 - 14:50 Holger Waubke timmung analytischer Lösungenfür ein hysteretisches Modell von Bouc Frame Theory for Acoustical Applica- 14:50 - 15:10 Peter Balazs tions Auditory time-frequency masking for 15:10 - 15:30 Thibaud Necciari stimuli with maximal concentration in the time-frequency plane 15:30 - 15:50 Coffee break

63 Thursday, 20th September 2012, LS 15.02 15:50 - 18:00 Modelle zur Vorhersage der Schallquel- 15:50 - 16:10 Robert Baumgartner lenlokalisation in Sagittalebenen Beschleunigung der nu- 16:10 - 16:30 Harald Ziegelwanger merischen Berechnung von Außenohr¨ubertragungsfunktionen ExpSuite: Software Framework zur Durchf¨uhrung psychoakustischer Ex- 16:30 - 16:50 Michael Mihocic perimente mit akustischer, elektrischer und visueller Stimulusdarbietung Bayesian estimation of the area func- 16:50 - 17:10 Christian Kasess tion of nasals 17:10 - 17:30 Wolfgang Kreuzer Wavelets on the sphere Eigenmoden – Raummoden; theoretis- 17:30 - 17:50 Martin Pobitzer che Betrachtungen und Simulationen in COMSOL Multiphysics

64 Thu, 10:00 - 11:00, LS 15.02

Thu, 10:00 Acoustic Interface for Tremor Analysis David Pirr´o1, Alexander Wankhammer1, Alois Sontacchi1, Robert H¨oldrich1

1UniversitätfürMusik und darstellende Kunst Graz, Inffeldgasse 10/3, 8010 Graz, Austria

Tremor is the most common movement disorder. It is defined as a rhythmic and involuntary oscillation of a body part, caused by reciprocal nervous innervations of muscles. The most common forms include the essential tremor, parkinsonian tremor, dystonic tremor and psychogenic tremor. It is well-known that each different tremor form can be the symptom of a specific disease. Therefore, reliable classification and quantification of different tremor types is of strong clinical interest, as it could be crucial in order to provide adequate treatment and medication for the patient. In many cases a confident clinical diagnosis mainly based on the visual analysis of a tremor by highly specialized neurologists experienced in movement disorders is possible. Nevertheless, in some situations uncertainty remains. Therefore, further investigations based on structural and functional imaging, video analysis, accelerometry and other electrophysiological investigations can be necessary. Although such methods offer important additional information for a final diagnosis, the ex-post analysis and interpretation of recorded data is typically very time-consuming and ex- pensive. The new sonification methods presented in this paper aim at extending established tremor analysis methods by an acoustical interface for tremor diagnosis. Based on real time sonification of acceleration data, detailed information on the temporal as well as spectral characteristics of tremor could be made audible to the neurologist while interacting with the patient. As sonification could provide an additional modality to perception, it would allow for a holistic analysis of the observed tremor avoiding the major drawbacks of ex-post analysis methods.

Thu, 10:20 Quellbreite von frontalen Phantomschallquellen: Wahrnehmung, Messung und Modellierung Matthias Frank1 1UniversitätfürMusik und darstellende Kunst Graz, Inffeldgasse 10/3, 8010 Graz, Austria

Phantomschallquellen sind Hörereignisse,die an einem Ort wahrgenommen werden, an dem sich keine Schallquelle befindet. Die einfachste Art Phantomschallquellen mithilfe von Lautsprech- ern zu erzeugen stellt die Stereophonie dar. Phantomschallquellen unterscheiden sich in ihrer wahrgenommenen Qualitätvon realen Schallquellen. Einer dieser Unterschiede ist eine Aufweitung der wahrgenommenen Quellbreite. Dieser Beitrag beschäftigtsich mit der Quellbreite von frontalen Phantomschallquellen. Die Phantomschallquellen werden durch gleichzeitigen Betrieb von 2 bzw. 3 symmetrisch aufstellten Lautsprechern erzeugt. Neben der Anzahl an aktiven Lautsprechern wird auch der Abstand zwischen diesen variiert. Die Wahrnehmung der Quellbreite wird zunächst in einem Hörversuch evaluiert. Die Versuchsergebnisse werden anschließend mit zwei aus der Rau- makustik bekannten Messgrößen fürdie Quellbreite (interauraler Kreuzkorrelationskoeffizient IACC und Seitenschallgrad LF) verglichen. Weiters wird eine angepasste Methode zur Messung des Seit- enschallgrades vorgestellt, die die Eignung dieser Messgrößefürsimultanen Schalleinfall verbessert. Der Beitrag schließt mit einem einfachen physikalischen Modell zur Vorhersage der wahrgenommenen Quellbreite.

65 Thu, 10:40 Einfache, auf Kammﬁlter beruhende Phantomschallquellenaufweitung Franz Zotter1, Matthias Frank1

1UniversitätfürMusik und darstellende Kunst Graz, Inffeldgasse 10/3, 8010 Graz, Austria

Die geeignete Ansteuerung eines symmetrisch zum Hörplatzstehenden Lautsprecherpaares kann ein Hörereignisvariabler Breite erzeugen. Am schmalsten ist dieses Hörereignis,die so genan- nte Phantomschallquelle, wenn beide Lautsprecher mit dem selben Signal versorgt werden. Es ist allgemein bekannt, dass sich die wahrgenommene Richtung dieser Phantomschallquelle durch breitbandige Laufzeit- und Pegelunterschiede an variable Richtungen zwischen den Lautsprechern lenken lässt. Darüber hinaus beschreibt die Literatur über Stereophonie, dass entlang der Fre- quenz uneinheitliche Pegel- und Laufzeitunterschiede dazu geeignet sind, die Phantomschallquelle aufzuweiten. Eine kürzlich vorgestellte laufzeitbasierte Methode ist zwar effizient, scheint aber nur am zentralen Abhörplatzgut zu funktionieren. Dieser Beitrag stellt deshalb einen effizienten pegel- basierten Ansatz vor und vergleicht beide Ansätzean einem seitlichen Abhörplatz.

66 Thu, 14:30 - 15:30, LS 15.02

Thu, 14:30 Gaussian Closure Technik fürdie Bestimmung analytischer Lösungenfürein hysteretisches Modell von Bouc Holger Waubke1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Das Modell von Bouc wurde fürdie mathematische Beschreibung des hysteretischen Verhaltens von Gummi entwickelt [1]. Im Vortrag sollen weitgehend analytische Beschreibungen fürdie Mo- mente einer mehrdimensionalen Normalverteilung der Zustandsgrößendes Modells von Bouc auf Basis der Gaussian Closure Technik [2] gewonnen werden. Dabei wird ein explizites Zeitschrittver- fahren fürden instationären Fall und ein implizites nichtlineares Gleichungssystem fürden sta- tionärenFall hergeleitet [3]. Das implizite Gleichungssystem läßtsich rasch lösen. Dabei treten keine Parameterkombinationen auf, die zu chaotischen Verhalten, wie bei der statistischen Lin- earisierung führen. [1] Bouc, R.: Forced Vibrations of a Mechanical System with Hysteresis (abstract), Proceedings of the 4th Conference on Nonlinear Oscillations, Prag, 1967, pp.315 [2] Caughey, T.K.; Dienes, J.K: Analysis of a Nonlinear First-Order System with a White Noise Input, Journal of applied Physics, Vol.33 No.11 Nov. 1961, pp. 2476-2479 [3] Waubke, H. : Moment-Closure Technik zur Abschätzungder elasto-plastischen Reaktion von Stockwerksrahmen auf zufälligeBelastungen aus Windereignissen, Habilitation, Berichte aus dem konstruktiven Ingenieurbau, TU München, 1/1999

Thu, 14:50 Frame Theory for Acoustical Applications Peter Balazs1 1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Application-oriented mathematics develops theoretical results and new mathematical concepts, motivated by application. The application-oriented approach produces results signiﬁcant both for mathematics and the applied sciences. In this talk we will present an overview of new concepts in frame theory motivated by signal processing and acoustical applications. We will present a survey over general frame theory, time-frequency analysis and the theory of frame multipliers, as well a their applications in acoustics.

67 Thu, 15:10 Auditory time-frequency masking for stimuli with maximal concentration in the time-frequency plane Thibaud Necciari1, Bernhard Laback1, Peter Balazs1, Sophie Savel2, Sabine Meunier2, Sølvi Ystad2, Richard Kronland-Martinet2

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria 2Laboratoire de M´ecanique et dAcoustique, 31 chemin Joseph Aiguier, 13402 Marseille Cedex 20, France

Many audio applications involving sound analysis-synthesis (e.g., virtual reality, sound design, perceptual audio coding) use time-frequency (TF) representations such as the Gabor and wavelet transforms. These transforms allow decomposing any natural sound into a set of elementary functions or “atoms” that are well localized in the TF plane. For such applications, it is often required that the signal representation matches human auditory perception. On that purpose, the present study investigated auditory TF masking using stimuli with maximal concentration in the TF plane. Stimuli (masker and target) were Gaussian-shaped sinusoids with an equivalent rectangular band- width of 600Hz and an equivalent rectangular duration of 1.7ms (0-amplitude duration of 9.6ms). The masker had a carrier frequency of 4kHz and a level of 60dB SL. The target was shifted either in time, in frequency, or both relative to the masker. The results of the TF shifts provide the TF spread of masking produced by a maximally-compact Gaussian TF atom. These results constitute a crucial basis for predicting masking in the TF representations of sounds. The results of the time and frequency shifts allowed to show that a simple superposition of frequency and temporal masking functions does not provide an accurate representation of the measured TF masking function. This reveals the inaccuracy of the simplistic models of TF masking currently implemented in some perceptual audio codecs.

Thu, 15:30 - 15:50: Coﬀee break

68 Thu, 15:50 - 18:00, LS 15.02

Thu, 15:50 Modelle zur Vorhersage der Schallquellenlokalisation in Sagittalebenen Robert Baumgartner1, Piotr Majdak1, Bernhard Laback1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Die Fähigkeit, Schallquellen in Sagittalebenen zu lokalisieren, basiert auf spektralen Merk- malen, die aus der Filterung des einfallenden Schalls durch Torso, Kopf und Ohrmuschel resultieren. Obwohl diese Filterwirkung bereits seit langer Zeit bequem mittels sog. head-related transfer functions (HRTFs) beschrieben werden kann, erlauben derzeitige Modelle noch nicht die Vorhersage der Schallquellenlokalisation in Sagittalebenen. Dieser Beitrag beschreibt existierende Modelle zur Vorhersage der Schallquellenlokalisation sowie mögliche Erweiterungen fürden verbesserten Vergle- ich mit psychoakustischen Experimenten. Es wird eine Methode zur Vorhersage der individuellen Lokalisationsleistung mit individuellen HRTFs vorgestellt. Weiters wird der Effekt der Einbettung verschiedener Modelle des peripheren Gehörsim Lokalisationsmodell auf die Vorhersage der Lokali- sation unter diversen Bedingungen beschrieben.

Thu, 16:10 Beschleunigung der numerischen Berechnung von Außenohr¨ubertragungsfunktionen Harald Ziegelwanger1, Wolfgang Kreuzer1, Piotr Majdak1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Außenohrübertragungsfunktionen (engl. head-related transfer functions, HRTFs) ermöglichen die Lokalisation von Schallquellen bei binauraler oder transauraler Wiedergabe und werden üblicher Weise in einem reflexionsarmen Raum unter Freifeldbedingung füreine begrenzte Anzahl an Posi- tionen akustisch gemessen. Die Berechnung von HRTFs über die Randelementemethode stellt eine gut geeignete Alternative dar, da sie unter Ausnutzung der Reziprozität(Tausch von Quelle und Empfänger)effizient die Simulation des durch den ZuhörergestörtenSchallfeldes im Freifeld und somit die Berechnung der HRTFs fürbeliebige Positionen im Raum ermöglicht. Dafürgenügtallein die Kenntnis der Geometrie von Pinna, Kopf und Torso, welche die Filterwirkung verursacht und durch bildgestützteMessverfahren (3D-Laserscan) oder durch bildgebende Messverfahren (Kern- spintomographie) als 3D-Mesh erfasst werden kann. Um die HRTFs fürden gesamten hörbaren Frequenzbereich berechnen zu können,muss das zugrundeliegende Mesh eine hohe Genauigkeit aufweisen (ca. 6-10 Elemente pro Wellenlänge). Eine höhereGenauigkeit bewirkt allerdings eine längereRechendauer bei der Simulation. In diesem Vortrag werden verschiedene Ansätzezur Re- duktion der Rechendauer bei der HRTF-Berechnung über die Randelementemethode vorgestellt. Es werden numerische Optimierungen wie zum Beispiel ein parametrisches Mesh, die Fast-Multipole- Methode oder H/H-Matrizen diskutiert. Aufgrund der optisch schwer erfassbaren und komplexen Struktur der Pinna wird vorgeschlagen ein strukturiertes Pinna-Modell zu entwickeln und an die individuelle Anthropometrie anzupassen.

69 Thu, 16:30 ExpSuite: Software Framework zur Durchf¨uhrung psychoakustischer Experimente mit akustischer, elektrischer und visueller Stimulusdarbietung Michael Mihocic1, Piotr Majdak1, Bernhard Laback1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

In diesem Beitrag wird ExpSuite, eine Software zur Durchführungpsychakustischer Experi- mente vorgestellt. ExpSuite besteht aus einem Framework und darauf basierenden Applikationen. Sie profitiert von der “Rapid Application Development”-Umgebung in .NET, die eine schnelle Entwicklung der Experimente ermöglicht. Durch den modularen Aufbau könnenApplikation- sprogrammierer die Eigenschaften der Applikationen selbst definieren: Generierung einer “Item list” mit Testparametern und Ergebnissen, Erzeugung und Wiedergabe der Stimuli, Ablauf des Experiments und Auswertung der Ergebnisse. Das Framework unterstütztprozedurale Eigen- schaften wie zeitliche Struktur (adaptive und ineinander verschachtelte Abläufe), Parametrierung experimenteller Schritte, Steuerung über Joypad, Maus, Tastatur, Touchscreen, oder Position- serfassungsysteme. Damit kann sich der Applikationsprogrammierer auf die Entwicklung des experimentellen Designs konzentrieren. Mit der direkten Anbindung an Matlab steht ExpSuite- Applikationen eine Vielfalt von Matlab Funktionen zur Verfügung,die auch zur direkten Auswer- tung der Ergebnisse verwendet werden können. Die Ausgabe der Stimuli in vektororientierter Form kann über akustische Audiogeräteoder als elektrische Stimulation über ein Cochleaimplantat- Interface erfolgen. Das Programm Pure Data (pd) übernimmt die akustische Signalverarbeitung in Echtzeit (komplexe Filterung und Signalgenerierung), die Ausgabe der Stimulationsdateien, sowie die simultane Aufnahme und Wiedergabe mehrerer Audiokanäle. Zur Echtzeitdarstellung einer virtuellen visuellen Welt wird GEM unter pd verwendet. Die elektrische Stimulation zur Durchführungvon Experimenten mit Cochleaimplantat-Trägernerfolgt über die Research Interface Boxen (RIBs), die eine binaural synchronisierte Stimulation von Implantaten unterstützen.Exp- Suite wird am Institut fürSchallforschung entwickelt und ist unter http://expsuite.sourceforge.net frei verfügbar.

Thu, 16:50 Bayesian estimation of the area function of nasals Christian Kaseß1, Wolfgang Kreuzer1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

Computational acoustical models for speech production and analysis have been of major research for decades. Most commonly, one-tube models are employed which show a direct correspondence to all-pole filter models. However, such models are not an adequate representation for nasal stops and nasalized vowels due to the coupling to the nasal tract. Thus, at least one additional coupled tube is necessary to model the spectral dips typically appearing in nasal speech signals. Typically, the estimation of such branched-tube area functions is based on pole-zero models. Here, the tube model areas are estimated directly from the log-envelope of the spectrum of the speech signal. A variational Bayesian scheme under Gaussian assumptions is employed that utilizes probabilistic priors to enforce smoothness of the estimated area function. Different prior variances are tested on tokens of /m/ recorded from several speakers. Furthermore, results of an un-regularized non-linear scheme are compared to the Bayesian estimation. The model error and marginal likeli- hood show that mild smoothness assumptions yield the best results. The estimation error for the un-regularized scheme is in a comparable range, however, the reflection coefficients and thus the area functions vary considerably more within a subject than for the Bayesian scheme.

70 Thu, 17:10 Wavelets on the sphere Wolfgang Kreuzer1

1Osterreichische¨ Akademie der Wissenschaften, Wohllebengasse 12-14, 1040 Wien, Austria

For numerous applications in acoustics a spatial representation of wave fields supporting a local other than a global resolution is advantageous. Such applications range from wave field synthesis to numerical methods like the fast multipole method. As an alternative to the often applied spherical harmonic analysis, wavelets or - more general - frames can achieve a more efficient representation. Although wavelet analysis has been proven to be useful in many applications in audio and signal- processing and wavelets on the sphere have been of research interest in geophysics and computer vision for several years now, their potential for representing three-dimensional acoustic wave fields has not been fully explored yet. In this talk, a short overview of available methods to construct and use wavelets (and frames) on the sphere will be presented.

Thu, 17:30 Eigenmoden - Raummoden; theoretische Betrachtungen und Simulationen in COMSOL Multiphysics Martin Pobitzer1, Stefan Plagg1, Gerhard Graber1

1Graz University of Technology (TU Graz), Inﬀeldgasse 16c/EG, 8010 Graz, Austria

Dieser Beitrag beschäftigt sich mit der Ausbildung von stehenden Wellen im Raum. Da in diesem Zusammenhang die Begriffe “Eigenmoden” und “Raummoden” oft verwechselt werden, ist einer der Kernpunkte die Unterschiede beider Begriffe aufzuzeigen. Nach einer Einführungin die Thematik wird eine Eigenfrequenzanalyse fürverschiedene Raumtypen durchgeführtund der Einfluss von verschiedenen Wand- und Deckenformen untersucht. Die Ergebnisse werden unter anderem mit Hilfe von Animationen präsentiert. Der zweite Teil behandelt die Frequenzbereich- sanalyse, mit deren Hilfe der Einfluss von Quellposition und Beobachter- bzw. Mikrofonposition auf die Raummodenausformung untersucht wird. Die Arbeit wurde im Rahmen eines Bachelorseminars am Institut fürSignalverarbeitung und Sprachkommunikation (spsc) der Technischen UniversitätGraz erstellt.

71 72 7 Atoms, Molecules, Quantum Optics and Plasmas (AMP) LS 15.01

Atoms, Molecules, Quantum Optics and Plasmas Atome, Molek¨ule,Quantenoptik und Plasmen: Hanns-Christoph N¨agerl, [email protected]

Thursday, 20th September 2012, LS 15.01 09:00 - 11:00 Time Presenter Title Carbohydrate-Aromatic Complexes 09:00 - 09:20 Thomas Betz Investigated by Broadband Microwave Spectroscopy The calculation of ESR line shifts of 09:20 - 09:40 Andreas Hauser alkali-metal atoms (Li, Na, K, Rb) on helium nanodroplets Non-linear atom optics with Bose- 09:40 - 10:00 Thorsten Schumm Einstein condensates Absolute single molecule detection eﬃ- 10:00 - 10:20 Michele Sclafani ciency for a superconducting nanowire Controlled coupling of quantum dots 10:20 - 10:40 Christian Gruber to nanowire plasmons EEL-mapping of plasmon modes on a 10:40 - 11:00 Franz Schmidt silver nano disk 11:00 - 11:30 Coﬀee break

Thursday, 20th September 2012, LS 15.01 14:30 - 15:50 Time Presenter Title Superradiance and cascaded decay of 14:30 - 14:50 Laurin Ostermann regular arrays of trapped atoms Rubidium atom Rydberg states per- 14:50 - 15:10 Florian Lackner turbed by superﬂuid helium nanodroplets Laser induced acoustic desorption of 15:10 - 15:30 Carolina Matias biomolecules 15:30 - 15:50 Coﬀee break

73 Thursday, 20th September 2012, LS 15.01 15:50 - 18:00 Time Presenter Title Roughness and crystallinity contri- 15:50 - 16:10 Andreas Hohenau butions to surface-enhanced light- molecule interactions Fano resonances in photoionization 16:10 - 16:30 Andreas Kautsch spectra of chromium in helium nanodroplets 16:30 - 16:50 Katrin Tanzer Electron Interactions with Explosives Quantum chemical studies of Cr atoms 16:50 - 17:10 Johann Pototschnig on superﬂuid He nanodroplets Combination of Fourier transform- and 17:10 - 17:30 Laurentius Windholz laser spectroscopy to ﬁnd unknown atomic energy levels New energy levels of the neutral Pr 17:30 - 17:50 Bettina Gamper atom in the IR region

74 Thu, 09:00 - 11:00, LS 15.01

Thu, 09:00 Carbohydrate-Aromatic Complexes Investigated by Broadband Microwave Spectroscopy Thomas Betz1,2, David Schmitz1,2, Alvin Shubert1,2, Melanie Schnell1,2

1Center for Free-Electron Laser Science, Notkestrasse 85, 22607 Hamburg, Germany 2Max-Planck-Institut f¨urKernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany

A new broadband microwave spectrometer for the structural investigation of biologically relevant molecules in the gas phase is presented. The set up will be used to study the recognition of cyclic carbohydrates and aromatic molecules. This interaction is of signiﬁcant importance in biological systems, for example, the recognition of cells by lectins. The carbohydrate partners will be represented by gluco-, galacto and fucopyranose, whereas benzene, indole, and tryptophan serve as model molecules for the aromatic recognition sites. The complexes will be formed by simultaneously seeding them into a supersonically expanding noble gas. The rotational spectra of these complexes will be recorded by employing the novel Chirped Pulse Fourier Transform Mi- crowave (CPFTMW) spectroscopy technique1. This will allow the fast acquisition of the molecular response to microwave radiation in the range of 2 to 8 GHz and thus enables the comparison of diﬀerent molecular Earlier investigations used infrared ion dip (IRID) vibrational spectroscopy to characterize the involved binding mechanism of these systems2. Measuring the rotational spectra will complement this work by allowing the direct investigation of the structure of the molecular complexes. This knowledge will deepen the understanding of the conformational properties and changes involved in the recognition process.

Thu, 09:20 The calculation of ESR line shifts of alkali-metal atoms (Li, Na, K, Rb) on helium nanodroplets Andreas Hauser1, Thomas Gruber1, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

The line positions of electron spin resonance transitions (ESR) in alkali atoms are shifted for atoms attached to superfluid helium nanodroplets [1]. First attempts to describe the observed dependence of the hyperfine structure constant on the droplet size were based on a perturbational approach to the interaction between the He-cluster and the dopant, using the excited states of free alkali-metal atoms as basis sets for the matrix representation of the perturbation operator [2,3]. In an alternative approach we start from the analysis of the He-X dimers (X = Li, Na, K, Rb) with standard methods of quantum chemistry. Spin densities at the alkali atom, causing the isotropic part of the hyperfine interaction, can be calculated rather easily from most program packages at the Hartree-Fock (HF) level. Unfortunately, the weak van der Waals interactions between alkali atom and helium have to be treated at post-HF levels to obtain reasonable results. At least for Rb the inclusion of relativistic corrections is also indispensable. Furthermore, the experimental cluster sizes are out of range for any code based on molecular orbital theory. As a consequence, we try to reproduce the observed shifts by combining relativistic ab initio calculations for the He-X dimer systems with a simulation of full helium droplets based on density-functional theory. [1] Koch, M., Auböck, G., Callegari, C., Ernst, W. E., Phys. Rev. Lett. 103(3), 03530214(2009) [2] Koch, M., Callegari, C., Ernst, W. E., Mol. Phys. 108, 10051011(2010) [3] Callegari, C., Ancilotto, F., J. Phys. Chem. A 115, 67896796(2011)

75 Thu, 09:40 Non-linear atom optics with Bose-Einstein condensates Thorsten Schumm1, Tarik Berrada1, Jean-Francois Schaff1, Sandrine Van Frank1, Robert Bücker1, JörgSchmiedmayer1

1Technische Universit¨atWien - Atominstitut, Stadionallee 2, 1020 Wien, Austria

Realizing building blocks of photon quantum optics for matter waves is a long-standing goal. We present an eﬃcient source for twin-atom beams, in analogy to parametric down-conversion in non-linear optics. The source shows strong non-classical correlations in the population of the two beams, - 10dB below the classical limit. We also realized an integrated Mach-Zehnder interferometer for matter waves by combining a spatial beam splitter for BEC, a gravity-dependent phase-shifter and a recombined based on a pulsed Josephson tunnel junction. The intrinsic non- linearity of the matter waves leads to number squeezing in the splitting process and to fundamental phase diﬀusion in the interferometer sequence. We will discuss performance limits towards matter wave metrology.

Thu, 10:00 Absolute single molecule detection eﬃciency for a superconducting nanowire Michele Sclafani1, Markus Arndt1

1University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria

We present a study of the absolute single-particle detection eﬃciency of a 100 nm wide 4 nm thick NbN meander for ions in the low kinetic energy regime (0.2-1 keV) . We prove the capability of recording atomic and molecular ion signals in an energy range much lower than typically used in mass spectrometry and we show that up to a 100% detection eﬃciency can be achieved within our experimental setting. Superconducting nanowire devices have recently been proposed as an ideal alternative detection scheme for ionized [1,2] and neutral [3] particle beams. The detection process relies on the local suppression of superconductivity as the kinetic energy of the incoming particle is transferred to the electronic system of the wire. The impact of a molecule with the detector surface results in the rise of a resistive nanosecond voltage pulse when the wire is biased with a constant current. Finally we focus on the role of surface adsorbates in the detection process, which has remained neglected in all previous study so far, and we suggest new future strategies for optical spectroscopy on molecules, nanoparticles or helium nanodroplets. [1] M. Sclafani et al., Nanotechnology 23 (2012) [2] K. Suzuki et al., Rapid Communication Mass Spectrometry 24 (2010) [3] M. Marksteiner et al, Nanotechnology 20 (2009)

76 Thu, 10:20 Controlled coupling of quantum dots to nanowire plasmons Christian Gruber1, Primoz Kusar1, Andreas Hohenau1, Joachim Krenn1

1University of Graz, Universit¨atsplatz5, 8010 Graz

The diameter of dielectric waveguides is limited by the wavelength of the guided light. In contrast, gold and silver nanowires can sustain propagating plasmon modes even for significantly smaller dimensions. Furthermore the strong field localization of the nanowire plasmon modes leads to a strong interaction with nearby quantum emitters such as quantum dots. We use electron beam lithography, first, to fabricate silver nanowires and, second, to position a few dots close to one nanowire end in a template-assisted process. Scanning a focused laser spot over the nanowire ends, we demonstrate both, the excitation of nanowire modes by quantum dots and the addressing of the same dots by plasmons. We use the fluorescence signals to quantify the quantum dots/plasmon coupling and show that part of the plasmon-induced dot fluorescence couples back to plasmonic modes.

Thu, 10:40 EEL-mapping of plasmon modes on a silver nano disk Harald Ditlbacher1, Franz Schmidt2, Ulrich Hohenester1, Andreas Hohenau1, Ferdinand Hofer2, Joachim Krenn1 1University of Graz, Universit¨atsplatz5, 8010 Graz 2Graz University of Technology, FELMI, Steyrergasse 17, 8010 Graz, Austria

Localized surface plasmons are collective oscillations of the conducting electrons of metal nano structures coupled to an evanescent electromagnetic field. We study the plasmonic eigenmodes of a silver nano disk with laterally resolved electron energy loss spectroscopy (EELS) and observe – beside the well-known dipolar, quadrupolar, hexapolar etc. modes – a new type of modes which we name breathing modes analogous to acoustic vibrations. The surface charge distributions of dipolar and multipolar modes show radial node lines whereas the node lines of breathing modes are circles. These breathing modes are elementary plasmonic excitations of metal nano disks which have not been observed up to now as they do not couple to propagating light fields efficiently. This means these modes can hardly be detected by optical far field spectroscopy and they are therefore called “dark” modes. Nevertheless these modes affect the coupling of nano disks with molecular dipoles or other metal nano structures.

Thu, 11:00 - 11:30: Coﬀee break

77 Thu, 14:30 - 18:00, LS 15.01

Thu, 14:30 Superradiance and cascaded decay of regular arrays of trapped atoms Laurin Ostermann1, Helmut Ritsch1, Hashem Zoubi1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria

Lifetime and energy of collective optical excitations in regular arrays of atoms are significantly modified by dipole-dipole interaction. While the limiting cases of very closely positioned or infi- nite arrays of regularly spaced atoms can be approximated well by the Dicke superradiance or an exciton-based model, the situation of finite regular configurations is hard to access analytically. So far, most treatments are restricted to the lowest excitation manifold and a truncation of the interaction length We develop a general approach covering the complete decay cascade from the fully inverted to the ground state. We explicitly calculate all shifts and decay rates for the two generic cases of a 3-atom linear chain and an equilateral triangle and show their relation. In numerical calculations we show that despite fairly weak two-partite interactions, significant effects can build up in larger arrays through multi-particle interference. This changes the dephasing and decay properties in Ramsey experiments as well as the stability of superradiant lasers on narrow atomic lines as atomic clock transitions.

Thu, 14:50 Rubidium atom Rydberg states perturbed by superﬂuid helium nanodroplets Florian Lackner1, G¨unter Krois1, Markus Koch1, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Spectroscopy of rubidium atoms on the surface of helium droplets (HeN) of different sizes gives information about the influence of a nanosized superfluid on rubidium Rydberg states. We present the excitation spectrum of the Rb-HeN system from the 52D state manifold up to the ionization threshold, recorded by resonant three-photon-ionization time-of-flight spectroscopy [1, 2]. In ad- 2 dition to transitions from the 5 P1/2 intermediate state into nS and nD states, transitions into nP and nF states are observed. These transitions are allowed because of the reduced symmetry of the Rb-HeN system, which has a diatomic-like character. The observed transitions are broadened and shifted with respect to bare atom states, which is explained by a decreased quantum defect and a lowered ionization threshold within the scope of a Rydberg model. A set of six Rydberg series could be identified. Individual Rydberg states are observed with effective principle quantum numbers up to n∗ ≈ 19 and l ≤ 3, for which the expectation value of the electron orbital radius is about 10 times larger than the droplet radius. [1] Lackner, F., Krois, G., Koch, M., Ernst, W.E., J. Phys. Chem. Lett. 3, 1404-1408 (2012) [2] Lackner, F., Krois, G., Theisen, M., Koch, M., Ernst, W.E., Phys. Chem. Chem. Phys., 13, 18781-18788 (2011)

78 Thu, 15:10 Laser induced acoustic desorption of biomolecules Carolina Matias1, Johannes Postler1, David Gschliesser1, Marcelo Goulart1, Paul Scheier1, Stephan Deniﬂ1

1University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria

When high energy radiation interact with living cells it creates, along the ionization track, a set of secondary species. Low energy (<20eV) electrons are the most abundant ones and can induce strand breaks in DNA. The investigation of the inﬂuence of secondary particles in biomolecular systems, whether in the gas phase or in condensed phase, is a rich research area which applies both to gain fundamental knowledge and application-oriented results. Previous mass spectrometry experiments with low energy electrons dealt with small DNA building blocks and protein in the gas phase. In this work we perform free electron attachment studies to more complex systems like nucleotides. Typical experimental setups use ovens in which a sample of a certain biomolecule is heated and thereby evaporated. With the increasing size of the molecules there is a high risk of thermal decomposition. The advantage of using laser induced acoustic desorption is that one can prevent thermal decomposition and evaporate large molecules unbroken. The sample is applied as a very thin ﬁlm on a thin metal foil, and then the foil is irradiated at the backside with a pulsed laser. The laser pulses will create an acoustic wave, which propagates through the metal and desorbs the sample from the surface. Such a technique enables us to get large DNA building blocks or proteins into the gas-phase and makes it possible to investigate pure electron molecule interactions. This gives us important basic insight into the reactions happening in radiation damage.

Thu, 15:30 - 15:50: Coﬀee break

79 Thu, 15:50 - 18:00, LS 15.01

Thu, 15:50 Roughness and crystallinity contributions to surface-enhanced light-molecule interactions Andreas Hohenau1, Joachim Krenn1, Jean-Claude Tinguley1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Noble metal nanoparticles show specific optical properties due to the excitation of localized surface plasmons that give rise to surface enhanced absorption, fluorescence or Raman scattering. The nanoparticle geometry the dielectric properties of the metal and nanoscale surface roughness play an important role for surface enhanced effects, however they not yet well understood for lithographically fabricated nanoparticles. We approach this question by analyzing the optical characteristics of lithographically fabricated nanoparticles with different crystalinity and roughness parameters. They are varied by thermal annealing and a thin gold film is applied as a model system to retrieve modifications in the dielectric function. We investigate, on one hand, extinction spectra of metal nanoparticles that reflect the far-field properties of the plasmonic excitation and, on the other hand, surface-enhanced Raman spectra that serve as a near-field probe. Our results provide improved insight into localized surface plasmons and their application in light-molecule interactions.

Thu, 16:10 Fano resonances in photoionization spectra of chromium in helium nanodroplets Andreas Kautsch1, Matthias Hasewend1, Martin Ratschek1, Markus Koch1, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Ultracold He nanodroplets (HeN) at 0.4 K serve as ideal matrix to isolate and analyze single atoms with supporting effects from the interaction with the surrounding He [1]. Resonance ionization mass spectroscopy (RIMS) is a versatile technique to selectively excite and detect atoms. We combined these methods and carried out resonant two-photon ionization (R2PI) measurements on −1 Cr atoms in HeN in the wavelength range from 350 to 361 nm (27700 - 28600 cm ). Possible pathways leading to ionization include a strong first step y7P◦ ← a7S transition happening inside the droplet. This results in a broadening and a blue shift of about 7 nm enabling the possibility to obtain detailed information about the perturbation upon electronic excitation of the Cr atom in HeN [2]. Subsequently, the Cr atom leaves the droplet and simultaneously relaxes into lower lying states, which are spin and parity forbidden transitions. With a second photon of the same colour the ionization is accomplished through either continuum or autoionization states. We characterized Fano type resonances in terms of laser fluence saturation to get further insight into the various processes. [1] Ratschek, M., Koch, M., and Ernst, W. E., J. Chem. Phys. 136, 104201 (2012). [2] Callegari, C., and Ernst, W. E., in Handbook of High-Resolution Spectroscopy, eds. Quack, M., and Merkt, F., John Wiley & Sons, Chichester, 2011.

80 Thu, 16:30 Electron Interactions with Explosives Katrin Tanzer1, Benjamin Puschnigg1, Violaine Vizcaino1, Stephan Deniﬂ1, Paul Scheier1

1University of Innsbruck, Technikerstrasse 25/3, 6020 Innsbruck, Austria

In recent years a considerable interest in improving methods for the detection of explosives has arisen since the threat of attacks on planes and high risk buildings has grown steadily. Two methods for the detection working with electron-molecule collisions and mass spectrometry are presented and compared. Electron attachment of low energy electrons often leads to dissociation. In the case of explosive substances, every single explosive has a rich characteristic fragmentation pattern. This has been measured in our group for the explosives RDX and PETN amongst oth- ers. Together with the resonance profiles of the fragments even the distinction between isomers is possible, as shown for the three DNB isomers. Another possible technique for the detection of explosives is electron ionization where cations are formed by impact of electrons of about 70 eV. Usually considered a “hard” ionization method, electron ionization also leads to rich fragmentation patterns. Together with the ion efficiency curves and especially the appearance energy they form a unique fingerprint for every explosive. Mass spectra and appearance energies have been determined for several explosives including RDX, PETN and TNB. Considerable differences have been found even for the DNB isomers.

Thu, 16:50 Quantum chemical studies of Cr atoms on superﬂuid He nanodroplets Johann Pototschnig1, Martin Ratschek1, Andreas Hauser1, Markus Koch1, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

He nanodroplets (HeN) provide a superfluid quantum matrix at 0.4 K. Single atoms or molecules doped on HeN can be investigated and used to synthesize nanostructures that may be deposited on surfaces [1]. The location of the dopant on HeN affects the amount of spectroscopic perturbation and the formation of nanostructures on HeN. Cr has outstanding magnetic properties due to the septet ground state. In combination with He, a weak van der Waals molecule is formed which is challenging to describe theoretically. We calculated the Cr-He pair potential curve with different post Hartree-Fock methods. CCSD(T), CI, and multireference perturbation theory (RS) were applied, all including relativistic Douglas-Kroll corrections. After counterpoise correction we extrapolated to the basis set limit. The pair potential is applied to calculate the so-called Ancilotto parameter [2] and to DFT calculations for the He density [3]. Both methods indicate that Cr resides inside HeN. Our group also investigates the Cr-HeN complex experimentally by means of mass and laser spectroscopy. First experimental results will be reported besides the theoretical calculations. [1] Loginov E., Gomez L. F., Vilesov A. F., J. Phys. Chem. A 115, 7199 (2011) [2] Ancilotto F., Lerner P. B., Cole M. W., J. Low Temp. Phys. 101, 1123 (1995) [3] Dalfovo F., Lastri A., Pricaupenko L., Stringari S., Treiner J., Phys. Rev. B 52, 1193 (1995)

81 Thu, 17:10 Combination of Fourier transform- and laser spectroscopy to ﬁnd unknown atomic energy levels Laurentius Windholz1 1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Opposite to common assumptions, still not all energy levels of chemical elements are known. Thus it is quite often not possible to explain even strong spectral lines as transitions between certain energy levels. For elements which nuclei possess a spin quantum number I>0, the hyperfine structure constants can be used additional as finger print for a level. The hyperfine pattern predicted for a certain level combination then can be compared with the pattern in a highly resolved Fourier transform spectrum, and the line can be classified. Lines which can not be explained as combinations of known levels can be excited by laser light. The information gained from the observed hyperfine pattern (angular momenta J of the electron shell and hyperfine constants) together with excitation and fluorescence wavelengths can be used to find the properties of the up to now unknown energy levels. The existence of such level can be verified by the Fourier spectrum since such level must explain other lines with respect to hyperfine pattern and center of gravity wave number. A computer program which allows to handle data bases for spectral lines and levels of an element is presented.

Thu, 17:30 New energy levels of the neutral Pr atom in the IR region Bettina Gamper1, Imran Siddiqui1, Uddin Zaheer2, Laurentius Windholz1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Yanbu University College, Yanbu Industrial City 510000, P.O.box 31387, Kingdom of Saudi Arabia

With the help of the new Fourier transform spectra (FTS) of Pr [1] and with laser-induced fluorescence (LIF) spectroscopy it was possible to find a big amount of new energy levels in the past year [2], [3] and [4]. In the IR region we still do not have a suitable laser to perform LIF spectroscopy. Nevertheless for some well-resolved lines, we were able to investigate their structure and hence to introduce 21 new energy levels of the neutral Pr atom. All of them have odd parity and their J-value differs from 1/2 to 19/2. The appearance of the line in the FTS, the small components have to be resolved, gives us the J-value and the hf constants could be determined by fitting the hf pattern of the investigated line. All of the newly presented atomic levels explain a lot of so far not classified lines. As an example we discuss the line with the cg wavelength 9319.006 and the so determined level with an energy of 22442.185(5) cm−1, a J-value of 15/2 and a hf constant A of 959(9) Mhz (the hf constant B is assumed to be zero). [1] B.Gamper et al.; J. Phys. B. 44, 045003 (2011) [2] K.Shamim et al.; Eur. Phys. J. D 64, 209-220 (2011) [3] T.I.Syed et al.; Phys. Scr. 84, 065303 (2011) [4] Z.Uddin et al.; Journal of Physical Science and Application, in press

82 8 Solid State Physics (FKP) & Research with Neutron and Synchrotron Radia- tion (NESY) HS 15.12

Solid State Physics and Research with Neutrons and Synchrotron Radiation Festk¨orperphysik: Physik an Neutronen- und Synchrotronstrahlungsquellen Gottfried Strasser, [email protected] Ernst Bauer, [email protected]

Thursday, 20th September 2012, HS 15.12 09:00 - 11:00 Time Presenter Title Electro-elastic control of excitons in 09:00 - 09:30 Armando Rastelli single quantum dots Imaging of classical trajectories and 09:30 - 09:45 Roland Brunner quantum mechanical states in open quantum dots What can be obtained by bringing 09:45 - 10:00 Benedetta Marmiroli together small angle X-ray scattering and deep X-ray lithography? Core/shell profile of nanocrystals de- 10:00 - 10:15 Rainer Lechner termined by anomalous SAXS Supercrystals formed by monodisperse 10:15 - 10:30 Dominik Kriegner nanocrystals investigated by X-ray diffraction Investigations of radial and axial het- 10:30 - 10:45 Mario Keplinger erostructured nanowires using x-ray diffraction Quantum Dot Cavity Spin Entangle- 10:45 - 11:00 Walter Pötz ment at a Distance - A Theoretical Analysis 11:00 - 11:30 Coffee break

83 Thursday, 20th September 2012, HS 15.12 14:30 - 15:30 Time Presenter Title Martin Kaltenbrunner Power Supply, Generation and Storage 14:30 - 14:45 Anton Paar-Prize in Stretchable Electronics Disorder effects on resonant hole tun- 14:45 - 15:00 Christian Ertler neling transport in (Ga,Mn)As/GaAs heterostructures Prediction of room-temperature spin 15:00 - 15:15 Benjamin Stickler filtering in (CrAs/GaAs) heterostructures Dynamics of Dirac Fermions on Sur- 15:15 - 15:30 RenéHammer faces of Topological Insulators 15:30 - 15:50 Coffee break

Thursday, 20th September 2012, HS 15.12 15:50 - 17:35 Time Presenter Title Enhancing the detectivity of photonic 15:50 - 16:05 Peter Reininger crystal photodetectors by quality factor tuning Optimization of intersubband devices 16:05 - 16:20 Benedikt Schwarz for dual-color emission, absorption and detection Substrate emitting ring cavity quan- 16:20 - 16:35 Lukas Burgstaller tum cascade lasers Studies on the Coupling of Dielectric 16:35 - 16:50 Ronald Meisels and Plasmonic Waveguides using FEM and FDTD Simulations Superconducting properties of multi- 16:50 - 17:20 Michael Reissner ﬁlamentary MgB2 wires Combining SQUID magnetometry with in-situ cyclic voltammetry to 17:20 - 17:35 Stefan Topolovec study the electrochemical charging- induced variation of the magnetic moment of γ-Fe2O3 nanoparticles Transport beyond Brownian Motion – 17:35 - 17:50 Thomas Franosch Colored noise 17:50 FKP & NESY member meeting

84 Friday, 21st September 2012, HS 15.12 09:00 - 11:00 Time Presenter Title Comparison of MOS and Schottky- 09:00 - 09:15 Mattia Capriotti barrier structure in AlGaN/GaN HEMTs Interface Morphology of an Orthogonal 09:15 - 09:30 Alfred Neuhold Soluble Polymer Transistor Temperature Induced Wet- ting and Dewetting Effects of 09:30 - 09:45 Michael Dohr Dioctylbenzothieno-benzothiophene on Silicon Oxide Surfaces Metastable structures and phases of in- 09:45 - 10:00 David Geist termetallics produced by severe plastic deformation Quantitative analysis of liquid jets 10:00 - 10:30 Benedetta Marmiroli breakup with SAXS Direct measurements of reversible free-volume formation in bulk 10:30 - 10:45 Martin Luckabauer Zr56Al7Cu24Ni10Co3 glass below the glass transition temperature Positron annihilation spectroscopy 10:45 - 11:00 Peter Parz on LiCoO2-electrodes with different lithium content 11:00 - 11:30 Coffee break

Friday, 21th September 2012, HS 15.12 11:30 - 12:45 Time Presenter Title Self Assembly of Mesoporous Materi- 11:30 - 12:00 Heinz Amenitsch als in the Gas-Phase: An in situ SAD Study Mechanical properties of carbon 12:00 - 12:15 Markus Hartmann nanostructures investigated by Monte Carlo simulations Topologically nontrivial and nearly ﬂat 12:15 - 12:30 Maria Daghofer bands in multi-orbital models Itinerant electrons in a 2-dimensional 12:30 - 12:45 J¨ornVenderbos spin-ice system: Kondo-Lattice model on the checkerboard lattice

Thu, 09:00 - 11:00, HS 15.12

85 Thu, 09:00, Invited Electro-elastic control of excitons in single quantum dots Armando Rastelli1,2, Rinaldo Trotta1,2, Eugenio Zallo2, Paola Atkinson2, Oliver Schmidt2

1Johannes Kepler Universit¨atLinz, Altenberger Straße 69, 4040 Linz, Austria 2IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

Optically active semiconductor quantum dots (QDs) can be made as epitaxial nanoinclusions of a low energy bandgap material in a matrix with larger energy bandgap. Many recent experiments have demonstrated that these QDs are excellent quantum emitters, which can be used as sources of triggered single photons, indistinguishable photons and polarization entangled photon pairs. The structural properties of self-assembled QDs are affected by unavoidable fluctuations, which make it difficult to obtain QDs with electronic and optical properties which meet the - sometimes very stringent - requirements for their use in advanced quantum optics experiments. Post-growth techniques are therefore needed to fine-tune the optical properties of QDs. In this talk we will discuss QD-based devices in which the semiconductor structures are integrated on top of piezoelectric ac- tuators made of PMN-PT. This combination allows us to study in detail the effects produced by variable strains (up to about 0.3%) on the excitonic emission of single QDs and to manipulate reversibly and in a broad range the excitonic emission of single dots. In particular, by using diode- like nanomembranes we can simultaneously use elastic deformation and electric fields to control the electronic structure of QDs. This allows us e.g. to achieve independent control of emission energy and charge-state of a QD and to realize wavelength-tunable single-QD light-emitting diodes. Possible future extensions and applications of this technology will be discussed.

Thu, 09:30 Imaging of classical trajectories and quantum mechanical states in open quantum dots Roland Brunner1, Ronald Meisels1, Nobuyuki Aoki2, Yuichi Ochiai2, Richard Akis3, Adam Burke4, David Ferry3

1Montanuniversit¨atLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria 2Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan 3Arizona State University, P.O. Box 9309, Tempe, AZ 85287-9309, USA 4University of New South Wales, Sydney, NSW 2052, Australia

In this work, we show classical and quantum mechanical simulations as well as scanning gate microscopy (SGM) to probe the ballistic motion of electrons within an open GaAs/AlGaAs quantum dot (QD). SGM, in combination with transport measurements, can provide an interesting tool to image the motion of electrons in quantum systems [1]. Recently, it has been theoretically argued for an open QD that, due to the induced perturbation of the SGM tip the imaging of the original open QD states is ambiguous [2]. However in this theoretical approach a system with a hard wall potential was used. Our model calculations are performed by using a soft-wall as op- posed to a hard-wall potential. This potential is obtained from fully self-consistent calculations. From the classical and quantum mechanical simulations we are able to extract the electron trajectories and probability density, respectively. Conductance maps are recorded by using SGM. Here, a biased tip in a cryogenic SGM is scanned over the open quantum dot while a magnetic field is applied. We show that, for specific magnetic fields, the measured conductance images resemble the classical transmitted and backscattered trajectories and their quantum mechanical analogue [3]. The demonstrated direct imaging technique is essential for the fundamental understanding of wave function scarring and quantum decoherence theory. [1] M. A. Topinka et al., Science 289, 2323 (2000). [2] M. Mendoza and P.A. Schulz, Phys. Rev. B 71, 245303 (2005). [3] N. Aoki, R. Brunner et al., Phys. Rev. Lett. 108, 136804 (2012).

86 Thu, 09:45 What can be obtained by bringing together small angle X-ray scattering and deep X-ray lithography? Benedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1, Paolo Falcaro2, Luca Malfatti3, Marco Faustini4, Stefano Costacurta5, David Grosso4, Plinio Innocenzi3, Heinz Amenitsch1

1Osterreichische¨ Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria 2CSIRO, Gate 5 Normanby Rd, Clayton VIC 3168, Australia 3LMNT, Universit´adi Sassari, Palazzo Pou Salit, Piazza Duomo, 6 - 07041 Alghero (SS), Italy 4Universit Pierre et Marie Curie, 4 place Jussieu, Tour 54, E.5 Couloir 54-55, 75252 Paris Cedex 05, France 5CIVEN, Via delle Industrie 5, Torre Hammon, 30175 Venezia-Marghera, Italy

Micro-nanotechnology has melted away the borders between material science and biology. In fact, the miniaturization of chemical and biological assays, promoted by micro-nanofluidics, requires both a careful selection of the fabrication methods and the development of tailored materials for the specific applications. As a consequence, interdisciplinarity is becoming fundamental also in the combination of microfabrication and characterization techniques both aimed at the construction of new devices and at the development of novel materials for chemistry and biology applications. In this communication, we want to underline the advantages obtainable by combining two techniques: Deep X-ray Lithography (DXRL) for microfabrication and Small and Wide Angle X-ray Scattering (SAXS/WAXS) for investigation. On one hand DXRL makes it possible for SAXS to improve time resolution and create new sample environments. On the other hand SAXS permits the investigation of the nanostructural morphology of the microstructures fabricated by DXRL in order to tune the morphology for specific applications like nanosensors and biosensors or to determine the effect of irradiation on new materials. Examples will be presented to highlight both. First, microdevices fabricated for time resolved experiments of fast biological and chemical reactions, or for the study of the effect of confinement on crystal growth will be discussed. Then, the combination of bottom-up and top-down approaches for the development of new functionalized materials for which characterization with SAXS/WAXS is fundamental will be described.

Thu, 10:00 Core/shell proﬁle of nanocrystals determined by anomalous SAXS Rainer Lechner1, Gerhard Fritz-Popovski1, Maksym Yarema2, Wolfgang Heiss3, Oskar Paris1

1MontanuniversitätLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria 2Swiss Federal Laboratories for Material Science and Technology, Uberlandstrasse¨ 129, 8600 Dübendorf, Switzerland 3Johannes Kepler Universität Linz, Altenberger Straße 69, 4040 Linz, Austria

The infrared emission of lead chalcogenide nanocrystals (NCs) can be drastically increased sta- bilising the core with a hard protective shell [1]. In contrast to a shell growth on top of a core [2], we investigate in this study the CdS-shell growth on PbS NCs driven by Cd for Pb cation exchange [1]. We perform anomalous SAXS experiments at the synchrotrons HZB-BessyII and ESRF. Tun- ing the x-ray energy below the Pb-edge allows to record ASAXS spectra, where the contribution of Pb to the scattering signal is varied. This allows resolving the total electron density and the Pb-atom density inside the core/shell NCs independently. We derive the following results: During the exchange process applied to PbS spheres, the core shrinks, the CdS shell thickness increases, while the outer diameter as well as the size distribution remains constant. The CdS shell thickness ranges from 0.9 nm for 10 nm large PbS NCs to even 2 nm for 5 nm small NCs. The ﬁnal shell thickness scales with 1/D of the sphere diameter, related to an increased surface to volume ratio for the smaller NCs. For the thin CdS shells we found no reaming Pb within the shell, whereas for thick shells we detect 2 Pb atoms per cubic-nm within the shell. [1] H. Zhao, M. Chaker, N. Wu and D. Ma, J. Mater. Chem., 21, (2011) [2] M. Yarema, S. Pichler, M. Sytnyk, R. Seyrkammer, R.T. Lechner, et al., ACS Nano 5, (2011)

87 Thu, 10:15 Supercrystals formed by monodisperse nanocrystals investigated by X-ray diﬀraction Dominik Kriegner1, Maksym Yarema2, Tanja Etzelstorfer1, Mario Keplinger1, Mykhailo Sytnyk1, Wolfgang Heiss1, Maksym Kovalenko2, Julian Stangl1

1Johannes Kepler Universit¨atLinz, Altenberger Straße 69, 4040 Linz, Austria 2ETH Zurich, Department of Chemistry and Applied Biosciences, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland

Colloidal nanocrystals are subject of intense research because of their high potential for applications in electronic, magnetic and optical devices. Furthermore they show a high tendency to form ordered two and three-dimensional superstructures (“supercrystals”). The precise ordering in those supercrystals affects the electronic coupling between the individual nanocrystals and it was shown to lead to new collective properties. These properties are related to, and hence strongly affected by the degree of ordering obtained in the supercrystals, which in turn depends on nanocrystal size, the capping ligands and chemical species of chosen nanocrystals, as well as the monodispersity of the used nanocrystal batch. Thus, quantifying the degree of ordering and perfectness of supercrystals is of major interest, in order to enable a quantitative correlation between ordering and the ordering-dependent physical properties. To judge the quality of self-assembly obtained in 3D nanocrystal superlattices, we use X-ray diffraction, applied to individual supercrystallites. The supercrystals have typical sizes of 10µm, whereas the nanocrystals are below 20nm in diameter. While for two-dimensional arrays of self-assembled nanocrystals, ordering can be quantified by in- specting electron microscope images, for faceted 3D nanocrystal supercrystals, much more efforts have to be undertaken to obtain characteristic numbers, which allow to assess the degree of ordering obtained by the self assembly process. 3D reciprocal space maps are recorded at a synchrotron source using a micrometer sized X-ray beam, from which we find that the quality of ordering is strongly anisotropic.

Thu, 10:30 Investigations of radial and axial heterostructured nanowires using x-ray diﬀraction Mario Keplinger1, Bernhard Mandl1, Maria Messing2, Dominik Kriegner1, Julian Stangl1, Vaclav Holy3

1Johannes Kepler Universit¨atLinz, Altenberger Straße 69, 4040 Linz, Austria 2Lund University, S-22 100 Lund, Sweden 3Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic

The unique electronic, optical, and structural properties of semiconductor nanowires (NWs) allow the fabrication of suitable building blocks for future nanoelectronic and nanophotonic devices. Such applications require complex NW structures with either axial or radial NW heterostructures to provide for carrier confinement and/or for the waveguiding of light. Therefore we investigated samples with InAs1-x Px heterostructured NWs. These heterostructured NWs consist of an InAs core with an InAs1-x Px shell and heterosegment on top. The structural and chemical properties were investigated depending on the growth conditions. For one series with varied arsine/phosphine flow, and one with varied growth temperature, the average chemical composition, i.e. the phospho- rus content, the strain, and the dimensions were deduced using a combination of scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, and X-ray diffraction (XRD). The XRD data evaluation was done by calculating the strain distribution in a NW using finite element simulations. From this simulations the diffusely scattered intensity distribution was then calculated for a NW ensemble with a simple Monte Carlo method to account for statistical variations of the NW properties. A dependency of the P to As ratio in the hetero-segment on the arsine/phosphine precursor ratio was found with a proportionality factor of 0.75, whereas the variation of the growth temperature gave no variation of the chemical composition, but a change of the NWs aspect ratio.

88 Thu, 10:45 Quantum Dot Cavity Spin Entanglement at a Distance - A Theoretical Analysis Walter P¨otz1 1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Measurement of conditional Faraday rotation has recently been proposed for entanglement generation at a distance.[1-3] In this talk we present a theoretical analysis of entanglement formation at a distance between two electron spins, each sitting in one of two “distant” quantum dot cavities. Entanglement is induced by measuring the conditional Faraday rotation of a non–resonant laser pulse which has propagated through the two cavities. The basis for this scheme are two “identical” scatterers, such as an atom or a quantum dot, where each has two initial states, whereby only one of them is optically active, for example, by dipole selection rules. Here we investigate one–sided cavities which avoid unintentional measurement in the reflected beam.[4] Frequency “sweet–spots” are identified for which, in spite of dissipative action, good fidelity entanglement generation should be possible. We also predict that monitoring of the Faraday rotation allows the detection of single spin flips, similar to single non–demolition photo-emission monitoring in atom quantum cavity systems.[5] The possibility of studying entanglement death and revival in this system is discussed. [1] T. D. Ladd et al., New Journal of Physics 8, 184 (2006). [2] J. Grond, W. Pötz,and A. Imamoglu, Phys. Rev. B 77, 165307 (2008). [3] W. Pötz,Physical Review B 77, 035310 (2008). [4] W. Pötz,J. Comp. Electr., Volume 8 (1), 25-28 (2009). [5] M. Brune et al., Phys. Rev. Lett. 101, 240402 (2008).

Thu, 11:00 - 11:30: Coﬀee break

89 Thu, 14:30 - 15:30, HS 15.12

Thu, 14:30, Anton Paar-Prize Winner Power Supply, Generation and Storage in Stretchable Electronics Martin Kaltenbrunner1 1Johannes Kepler Universit¨atLinz, Altenberger Straße 69, 4040 Linz, Austria

Talk of the Anton Paar-Prize Winner.

Thu, 14:45 Disorder eﬀects on resonant hole tunneling transport in (Ga,Mn)As/GaAs heterostructures Christian Ertler1, Walter P¨otz1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Recent experiments on heterostructures comprising (Ga,Mn)As quantum wells [1] have evoked strong debates about the near absence of ferromagnetic order observed in these structures [2]. Here, we present a theoretical examination of these experimental results, studying the self-consistent interplay between ferromagnetic order, structural defects, and the hole tunnel current [3]. The hole band structure is described by a four band Kohn-Luttinger Hamiltonian and the transport characteristics are obtained within the non-equilibrium Green’s function approach. We show that disorder has a strong influence on the current-voltage (IV) characteristics in efficiently reducing or even washing out negative differential conductance, as found in experiment. The hole density in the quantum well is established through (tunneling) transport from the p-doped GaAs leads. We find that, for the Be lead doping levels used in experiment, the resulting spin density polarization in the quantum well only produces an exchange splitting of the order of a few meV, comparable to the experimental findings. We predict that the ferromagnetic order in the (Ga,Mn)As quantum well tends to be completely destroyed under resonance bias condition. This should lead to a characteristic bias-dependence of the spin-polarization (bias anomaly) of the tunnel current, available to experimental detection. Supported by FWF P21289-N16. [1] S. Ohya, K. Takata and M. Tanaka, Nature Physics, 7, 342 (2011). [2] T. Dietl and D. Sztenkiel, arXiv:1102.3267 (2011). [3] C. Ertler and W. Pötz,Phys. Rev. B 84, 165309 (2011).

90 Thu, 15:00 Prediction of room-temperature spin ﬁltering in (CrAs/GaAs) heterostructures Benjamin Stickler1, Christian Ertler1, Liviu Chioncel2, Enrico Arrigoni3, Walter P¨otz1

1University of Graz, Universitätsplatz5, 8010 Graz, Austria 2Zentrum fürElektronische Korrelationen und Magnetismus, UniversitätAugsburg, 86135 Augsburg, Germany 3Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Half-metallic materials are of profound interest in spintronic applications since, by definition, their density of states at the Fermi energy is 100 % spin polarized. Recent experiments as well as ab-initio calculations suggest that CrAs, grown epitaxially in the fcc structure on top of GaAs, is such a halfmetallic ferromagnet with a Curie temperature well above room temperature [1,2]. We present theoretical results, which suggest that spin-filtering in CrAs/GaAs heterostructures at room temperature could indeed be realized. Our theoretical approach consists of three crucial steps: In a first step we determine the spin-polarized band structure of lattice matched fcc bulk CrAs and a (GaAs)6/(CrAs)6 supercell. From these calculations we determine the band offset between the two materials as well as their bulk electronic structure. Within the second step we map the electronic structure of the bulk materials onto an effective 20-orbtial sp3d5s* nearest neighbor tight-binding (TB) model. In a third step we calculate current-voltage (IV) characteristics for heterostructures consisting of thin layers of CrAs embedded in a GaAs environment. The characteristics are determined within the non-equilibrium Green’s function formalism. The resulting IV characteristics provide an experimentally accessible fingerprint of the electronic structure of fcc CrAs and indicate that room temperature spin filtering should indeed be realizable in such systems. (Supported by FWF P221290-N16) [1] H. Akinaga, T. Manago, M. Shirai, Jpn. J. Appl. Phys., 39 (2000) [2] L. Chioncel et al. Phys. Rev. B, 83 (2011)

Thu, 15:15 Dynamics of Dirac Fermions on Surfaces of Topological Insulators Ren´eHammer1, Christian Ertler1, Walter P¨otz1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Topologically protected states may form at the surface of insulators with strong spin-orbit interaction[1]. Near the Kramer’s points, the electronic states can be mapped upon a mass-less 2+1 Dirac fermion Hamiltonian and the effective-mass term can be controlled by an external magnetic field (breaking time-reversal symmetry). In this talk we present some of our recent results from a theoretical study of the dynamics of 1+1 and 2+1 Dirac fermions simulated numerically on a lattice. For 1+1 dimensions we present and demonstrate perfect absorbing boundary conditions using algorithms which avoid fermion doubling. In 2+1 dimensions we present absorbing boundary conditions obtained from an imaginary potential in the asymptotic space regions[2]. For numerical examples we study several physical processes: wave packet propagation at a simple Klein step, a quantum interferometer[2], and a superlens realization. [1] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010). [2] Ren Hammer, Christian Ertler, and Walter Pötz,arXiv:1205.6941 (2012)

91 Thu, 15:30 - 15:50: Coﬀee break

Thu, 15:50 - 17:35, HS 15.12

Thu, 15:50 Enhancing the detectivity of photonic crystal photodetectors by quality factor tuning Peter Reininger1, Stefan Kalchmair1, Roman Gansch1, Aaron Maxwell Andrews1, Hermann Detz1, Tobias Zederbauer1, Werner Schrenk1, Gottfried Strasser1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria

An important figure of merit of photodetectors is the detectivity. A quantum well infrared photodetector (QWIP) has an inherent limitation to the detectivity at higher temperatures (above TBLIP), because an increase of the responsivity by higher doping increases the noise by about the same amount. Therefore, both effects cancel each other out. Another approach is to use a photonic crystal slab (PCS) as a resonant cavity in conjunction with a reduced doping concentration in the quantum wells. We have shown, that the noise due to dark current can be reduced significantly, while the high lifetime of photons in the PCS maintains a high responsivity. We present a PCS fabricated from a QWIP material. Under Globar illumination, an increase of the maximum operation temperature from around 110K for a standard QWIP up to 200K for a low-doped PCS-QWIP with a peak absorption at λ = 8µm was observed. The combined effect of responsivity enhancement and dark current noise reduction results in an enhanced specific detectivity D* of up to 20 times.

Thu, 16:05 Optimization of intersubband devices for dual-color emission, absorption and detection Benedikt Schwarz1, Peter Reininger1, Oskar Baumgartner2, Zlatan Stanohevic2, Hans Kosina2, Gottfried Strasser1 1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria 2Vienna University of Technology, Gußhausstrasse 27-29, 1040 Vienna, Austria

Quantum cascade lasers (QCL) and detectors (QCD) are powerful mid-infrared devices. A QCL can also act as a photovoltaic detector, but normally at a significant lower wavelength than the laser. Thus quantum cascade structures are commonly designed as either lasers or detectors. We have designed a dual wavelength quantum cascade structure that can act as coherent source and photovoltaic detector at the same wavelength. As a step towards monolithic integrated photonic circuits, such multipurpose devices open up new possibilities for on-chip applications by emitting, absorbing and detecting light on the same chip. Apart from typical real world applications, like chemical sensing, spectroscopy and free space communication, it can be used to study optical cou- plings, interaction of light and matter, as well as non-linear effects within one chip. Due to its complexity, such a device structure requires a careful quantum design to maximize performance, while matching the designed wavelength for both laser and detector operation. When a certain voltage is applied, the structure acts as a dual wavelength laser. At zero bias it acts as a photovoltaic detector or a. In this case, the injector states form a phonon ladder leading to a built-in electric field. After optical excitation the electrons can scatter via this phonon ladder to the lower level of the next period. The design fine tuning is done by an optimization algorithm based on a high efficient semi-classical Monte-Carlo quantum cascade simulator.

92 Thu, 16:20 Substrate emitting ring cavity quantum cascade lasers Lukas Burgstaller1, Clemens Schwarzer1, Sang Il Ahn1, Werner Schrenk1, William Charles2, Claire Gmachl3, Strasser Gottfried1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria 2Phononic Devices, Inc., Raleigh, North Carolina 27606, USA 3Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544, USA

Quantum cascade lasers (QCLs) evolved to versatile and reliable light sources in the mid- infrared (MIR) and terahertz (THz) spectral region. Recently, our group reported the ring cavity surface emitting QCL. The ring-type resonator, in combination with a second order distributed feedback grating (DFB) grating provides collimated beam profiles, along with robust single-mode emission. DFB gratings also diffract a certain amount of light towards the substrate. Within this work we perform investigations regarding the emission direction of ring-QCLs. A variation of the grating duty cycle (GDC) is performed to obtain an enhancement of the substrate emitted optical power. All devices showed single-mode operation at frequencies around 1296 /cm. Peak optical power values of 16.6 mW for surface emission and 9.25 mW for substrate emission were measured. When the GDC is not optimized for surface emission (around 70% ), a far greater amount of light is emitted through the substrate. Maximum values for substrate emission are found for GDCs around 56%. This agrees very well with the simulation results. When accounting for the substrate absorption and the transmission coefficient at the substrate-air interface, it is demonstrated that the whispering gallery modes are predominantly diffracted towards the substrate. The authors acknowledge the support by the Austrian projects IR-ON (FWF: F2503-N17) and PLATON, the GMe and MIRTHE (NSF-ERC, EEC 0540832).

Thu, 16:35 Studies on the Coupling of Dielectric and Plasmonic Waveguides using FEM and FDTD Simulations Ronald Meisels1, Markus Humer2, Oleksandr Glushko1, Roland Brunner1, Thomas Fromherz2

1Montanuniversit¨atLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria 2Johannes Kepler Universit¨atLinz, Altenberger Straße 69, 4040 Linz, Austria

An important goal for optimizing the transfer of light into and out of silicon based waveguides for integrated optics is the reduction of the footprint of the device on a chip. Therefore a hybrid dielectric/plasmonic coupling structure [1] is studied. The plasmonic modes of a gold strip of sub- skin-depth thickness couple symmetrically and asymmetrically to form long range (LRSPP) and short range surface plasmon polaritons (SRSPP) respectively. The dimensions of the gold strip are tuned to support effective-index-matching of the SRSPP mode and the fundamental mode of a SoI (Silicon on Insulator) based waveguide. Bringing the gold strip close to the dielectric waveguide results in a coupling of the individual modes forming two hybrid SRSPP/dielectric modes A and B which are nondegenerate, where their superpositions (A+B and A-B) are concentrated in the metal and in the dielectric, respectively. In accordance with coupled mode theory [2] optical power is transferred from the metal strip to the dielectric waveguide (or vice versa). The field distributions and phase velocities of the different structures are determined by the finite element method (FEM). The FDTD method is used to verify the coupling length. Because the SRSPP mode is so strongly confined to the metal strip very short coupling lengths were simulated, to use this device as an ultra-short coupler between plasmonic and dielectric structures. [1] Wan et al., Appl.Phy.Lett. 94, 141104 (2009) [2] Yariv & Yeh, Optical Waves in Crystals (2002), ISBN: 978-0471430810

93 Thu, 16:50, Invited Superconducting properties of multi-ﬁlamentary MgB2 wires Michael Reissner1, Stefan Sorta1, Lukas Bulla1, Tibor Melisek2, Pavol Kovac2

1Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria 2Slovak Academy of Sciences, D´ubravsk´acesta 9, 841 04 Bratislava, Slovak Republic

Many efforts are underway to produce multi-filamentary wires of MgB2, where the superconducting filaments are embedded in good conducting material. Unfortunately strong chemical reactions between MgB2 and Cu deteriorate superconducting properties strongly. Therefore barrier sheaths between both materials are necessary. For these Nb and Ti are found to be useable. The important question is, how superconducting properties depend on the reduction of both filament diameter and barrier thickness. In this work we report on magnetic investigation of a series of MgB2 wires, with nineteen filaments. All samples were prepared in the same way, but with filament diameters between 58.8 and 17.7 µm. With decreasing filament diameter the width of superconducting transition increases, although superconducting transition itself is not changed. Critical current density and irreversibility line also decrease. From magnetic relaxation measurements mean effective activation energies U are determined. They are also decreasing with decreasing filament diameter. The temperature dependence of U points to the existence of a pinning energy distribution, which broadens with decreasing filament diameter.

Thu, 17:20 Combining SQUID magnetometry with in-situ cyclic voltammetry to study the electrochemical charging-induced variation of the magnetic moment of γ-Fe2O3 nanoparticles Stefan Topolovec1, Heinz Krenn2, Roland W¨urschum1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

Electrical tuning of magnetic properties has emerged as an important topic of materials research in the last years. Recently, we could demonstrate that the magnetic moment of γ-Fe2O3 nanoparticles can be tuned reversibly by electrochemical charging [1]. In order to study the electrochemical processes taking place and their influence on the magnetic moment in more detail, we have now designed a special electrochemical cell, allowing the recording of cyclic voltammograms in-situ in a SQUID magnetometer. To charge the insulating γ-Fe2O3 nanoparticles, which were prepared by microwave plasma synthesis, a porous pellet of γ-Fe2O3 nanoparticles and Pt nanoparticles was formed. The charging of the pellet was performed in an aqueous electrolyte of 1M KOH. Reversible variations of the magnetic moment of γ-Fe2O3 nanoparticles up to several percent could be achieved. From the combined measurements of cyclic voltammograms and the magnetic moment it became obvious, that the charging coefficient s = ∆m/∆Q significantly depend on the examined potential range. The variation of the nanoparticles moment is considered to arise from reversible electrochemically induced reactions at the surface of the γ-Fe2O3 nanoparticles. In addition, charging induced variations of the magnetic surface anisotropy may play a role. Financial support by the FWF Austrian Science Fund is appreciated (project S10405-N16). [1] T. Traußnig et al., Phys. Status Solidi - Rapid Res. Lett. 5 (2011) 150.

94 Thu, 17:35 Transport beyond Brownian Motion – Colored noise Thomas Franosch1, Matthias Grimm1, Maxim Belushkin1, Flavio Mor1, Giuseppe Foffi1, LászlóForró1, Sylvia Jeney1

1Friedrich-Alexander-Universit¨atErlangen-N¨urnberg, Staudtstrasse 7, 91058 Erlangen, Germany

Brownian motion is one of the pillars of statistical physics with applications ranging from as- trophysics to biological physics. The theoretical foundation is well understood since Einstein and Smoluchowski introduced a probabilistic interpretation to derive diffusion as a macroscopic law. In modern language, the diffusion propagator follows from the central limit theorem. Although the mean-square displacement is dominated by the linear increase for long times and finite diffusion constant, persistent correlation underlying the transport may be unraveled by studying the corresponding velocity autocorrelation functions (VACF). I will discuss recent theoretical, simulation, and experimental advances highlighting power-law tails in the VACF which correspond to a colored component in the power spectrum of the force correlator due to hydrodynamic backflow [1,2]. [1] T. Franosch et al., Nature 478, 85-88 (2011) [2] S. Jeney et al., Phys. Rev. Lett. 100, 240604 (2008)

Thu, 17:50: FKP & NESY member meeting

Fri, 09:00 - 11:00, HS 15.12

Fri, 09:00 Comparison of MOS and Schottky-barrier structure in AlGaN/GaN HEMTs Mattia Capriotti1, Alexander Alexewicz1, Anil Parlar1, Frank Brunner2, Aaron Maxwell Andrews1, Dionyz Pogany1, Gottfried Strasser1

1Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria 2Ferdinand Braun Institut, Gustav-Kirchhoﬀ-Strasse 4, 12489 Berlin, Germany

GaN high electron mobility transistors (HEMTs) for power switching and digital applications require a low gate leakage current (Ig) and a high threshold voltage, allowing normally-off operation, but no common solution has been presented yet. It is known that engineering fixed charges at the barrier/oxide interface creates both normally-off and normally-on devices with the same heterostructure. In this work, we present a comparison between metal oxide semiconductors (MOS) and Schottky-barrier (SB) AlGaN/GaN HEMTs. We investigate devices with a heterostructure consisting of a 2 mm thick GaN buffer, 16 nm Al0:24Ga0:76N barrier and a 3 nm GaN:Si cap layer. In the MOSHEMT devices, after recessing the GaN cap layer below the gate, ZrO2 layers of 10 and 15 nm are deposited by atomic layer deposition on the barrier. Depositions were performed at 150◦C and at 2000◦C. In SB devices the Ni/Au gate metallization is deposited directly on the barrier. The SB samples show an exponential increase of Ig for a forward gate bias Vgf > 3 V, while the inclusion of a ZrO2 interlayer allows to increase the Vgf up to 8 V for the same Ig. Low values of Ig at a high gate bias indicate better gate oxide structural properties. Contrary to SB devices, the MOSHEMTs exhibit large hysteresis in the transfer characteristics, indicating charges at the interface ( 1012cm−2).

95 Fri, 09:15 Interface Morphology of an Orthogonal Soluble Polymer Transistor Alfred Neuhold1, Hannes Brandner1, Simon Ausserlechner1, Stefan Lorbek2, Markus Neuschitzer1, Egbert Zojer1, Christian Teichert2, Roland Resel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Montanuniversit¨atLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria

Understanding the interfacial properties of an organic multilayer arrangement is crucial when intending to use such structures in electronic devices. In this work we focus on the interface morphology of orthogonal soluble polymers in a solution processed polymer field effect transistor (PTFT). A water soluble poly-(4-styrenesulfonic acid) (PSSA) was solution deposited as a layer to modify the properties of the gate dielectric and on top of it the poly-(3-hexylthiophene) (P3HT) was spin cast as organic semiconducting polymer. Two relatively a-polar solvents (either chloroform or toluene), were used for the P3HT deposition. Gracing incidence X-ray diffraction was used to determine the orientation of the P3HT crystallites, which were face-on aligned for P3HT dissolved in chloroform and edge-on aligned for P3HT dissolved in toluene. The surface and interface roughness was investigated by X-ray reflectivity experiments and the surface roughness was cross-checked by atomic force microscopy. First experiments regarding the performance of these layers in thin-film transistors were conducted and revealed a one order of magnitude higher charge carrier mobility when spin-coating the P3HT film from toluene compared to the device for which chloroform has been used as solvent for P3HT deposition. This is assigned to the better defined PSSA/P3HT(toluene) interface morphology.

Fri, 09:30 Temperature Induced Wetting and Dewetting Eﬀects of Dioctylbenzothieno-benzothiophene on Silicon Oxide Surfaces Michael Dohr1, Oliver Werzer2, Quan Shen3, Roland Resel1, Christian Teichert3, Yves Geerts4, Michele Sferrazza4, Ingo Salzmann5

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2University of Graz, Humboldtstraße 46/I, 8010 Graz, Austria 3MontanuniversitätLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria 4UniversitéLibre de Bruxelles, CP 206/01 Campus de la Plaine, 1050 Bruxelles, Belgium 5Humboldt-Universitätzu Berlin, Unter den Linden 6, 10099 Berlin, Germany

The excellent performance of the molecule dioctyl-benzothieno-benzothiophene (C8-BTBT) in organic thin film transistors is strongly influenced by heat treatment. Spin coating of the film at elevated temperatures (within the liquid-crystalline state), leads to an increase in charge carrier 2 mobilities up to 3 cm /V s. The structural properties of C8-BTBT thin films are investigated as a function of temperature in terms of crystallographic properties and morphology. Spatially resolved microscopic methods (AFM and optical microscopy) as well as integral characterisation methods (Grazing incidence x-ray scattering, x-ray reflectivity) are used. The disordered monolayer film (thickness 2.4 nm) remains unstable after the spin coating process. With increasing temperatures, dewetting of the monolayer is observed by the formation of crystalline islands with an average height of about 15nm. Approaching the transition temperature to the smectic state, at a temperature of 90◦C, re-wetting is observed and a monolayer is formed on the substrate surface. This monolayer (thickness 2.9 nm) remains stable in the liquid crystalline state as well as after cooling back to room temperature. Also multilayer films show pronounced dewetting during heating by the formation of huge crystalline islands with a lateral size in the µm range. At 105◦C a monolayer (thickness 2.9 nm), at 108◦C a bilayer and at 115◦C a triple layer has developed. Decreasing temperatures reveal the reversibility of the layer-by-layer formation. All found layered structures can be stabilized by rapid cooling.

96 Fri, 09:45 Metastable structures and phases of intermetallics produced by severe plastic deformation David Geist1, Christoph Gammer1, Peter Karnthaler1, Christian Rentenberger1

1University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria

Metastable solid structures and phases such as nanostructured or amorphous phases are of general high scientific and technological interest since they often exhibit properties different from their crystalline, coarse-grained counterparts. In order to obtain metastable structures with an increased free energy different methods can be applied. In the last decade methods of severe plastic deformation were established to produce bulk materials comprising metastable phases. In this work we show the structural analysis of metastable structures and phases on different length scales using scanning (SEM) and transmission electron microscopy (TEM) methods. The metastable structures were produced by high-pressure torsion of L12 long-range ordered intermetallic alloys (Ni3Al, Zr3Al, Co3Ti) based on the fcc lattice. The SEM and TEM analyses show that the metastable structures evolve heterogeneously during deformation [1]. Depending on the type of lattice defects induced by deformation different saturation structures are produced: a nanocrystalline structure showing the loss of chemical long-range order (Ni3Al) or an amorphous one. TEM methods reveal that in Zr3Al the amorphous phase contains residual nanograins of the initial phases whereas in Co3Ti devitrified nanocrystals of a structure different to the initial one are embedded in the amorphous phase. In the latter case devitrification occurs in the course of deformation of the amorphous phase. [1] D. Geist, C. Rentenberger, H.P. Karnthaler. Acta Mater. 59 (2011) 4578. This work was supported by the Austrian Science Fund (FWF):[P22440]. The authors acknowledge the use of the SEM of the “Faculty Center for Nanostructure Research”.

Fri, 10:00, Invited Quantitative analysis of liquid jets breakup with SAXS Benedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1, Javier Perez2, Heinz Amenitsch1

1Osterreichische¨ Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria 2Synchrotron SOLEIL, L’Orme des Merisiers BP 48 Saint-Aubin, 91192 Gif sur Yvette Cedex, France

The breakup of liquid jets represents a wide area of research in the field of multiphase flows, fully justified by their wide presence both in industrial and in scientific applications. Moreover, the recent development of microfluidic systems has raised great interest in understanding the flows in small spatial dimensions. Such interest has been further increased due to the evolution of free electron lasers and the consequent need to develop new, high throughput techniques to characterize biological macromolecules. Jet instability has been widely described both theoretically and by performing sumulations, however there is still need to have accurate sets of experimental data. In fact most of them are based on light scattering which is disturbed by reflection, absorption and multiple scattering of droplets and air interface morphology, and on camera imaging which is limited by the dimension of the phenomena that can be seen. In the present communication we want to show the potentiality of synchrotron SAXS in providing quantitative information on the dynamics of liquid jets at the nanoscale. To this purpose, we have investigated free liquid jets in air with circular nozzle geometry of different diameters (450µm-100µm), flow rates (2-10 ml/min), and solvents (water, ethanol, isopropanol and their mixtures). We determined their time dependent morphology and their breakup length in the Rayleigh and first wind-induced regimes. The resulting data are considered as basis for the use of free jet micromixers to examine the evolution of chemical and biological reactions by SAXS.

97 Fri, 10:30 Direct measurements of reversible free-volume formation in bulk Zr56Al7Cu24Ni10Co3 glass below the glass transition temperature Martin Luckabauer1, Rainer Wunderlich2, Hans-J¨orgFecht2, Wolfgang Sprengel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Universit¨atUlm, Albert-Einstein-Allee 47, 89081 Ulm, Germany

Most models regarding the glass transition are based on information obtained from the su- percooled liquid state, either by experiment or by simulation. The slowing down of molecular or atomic motion occurring at the glass transition makes the kinetics difficult to access for common measurement techniques at lower temperatures. However, possible changes around Tg regarding the structural dynamics are believed to yield key parameters in understanding the glass transition. We report the measurement of thermally activated reversible formation and disappearance of free volume in bulk Zr56Al7Cu24Ni10Co3 glass by means of high-resolution laser dilatometry in the lower temperature regime around the glass transition. The measurement technique involving a 2-beam Michelson laser-interferometer is contactless and allows access to time constants of up to 1 × 106 s. From isothermal length change measurements at different temperatures after fast temperature changes the underlying atomic processes were studied. According to a first analysis the behavior can be described by an Arrhenius relation with high activation energy. Financial support by the Austrian Science Fund (FWF) is appreciated (project P22645-N20).

Fri, 10:45 Positron annihilation spectroscopy on LiCoO2-electrodes with different lithium content Peter Parz1, Werner Puff1, Roland Würschum1, Bernd Fuchsbichler2, Stefan Koller2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2VARTA Micro Innovation GmbH, Stremayrgasse 9, 8010 Graz, Austria

LiCoO2 is widely used in Li-ion battery systems as an intercalation electrode material. Re- versible charge/discharge cycling of LiCoO2 is only possible up to 50% of the available Li-ions, further removal of Li-ions drastically reduces the capacity and cycle stability. The extraction of lithium ions is expected to leave open volumes, which should act as positron traps. Therefore, Positron Annihilation Lifetime Spectroscopy (PALS) was applied on a LiCoO2 electrode material, to monitor the changes of the mean positron lifetime upon diﬀerent discharge levels. The electrodes consist of LiCoO2 with addition of carbon for electrical conductivity and a polymer binder. These electrodes were then discharged to LixCoO2, with x = 1, 0.8, 0.7, 0.6, 0.55, 0.5, 0.4 and 0.3. The electrodes were disassembled, rinsed and dried in argon atmosphere and ex-situ investigated by positron lifetime spectroscopy. For a lithium content of the LixCoO2 of x = 1 - 0.6 a linear increase of the mean positron lifetime could be monitored, which can be attributed to an increase in size and concentration of the free volume, due to missing lithium ions and in addition to a mon- oclinic distortion of the hexagonal structure, due to Coulomb repulsion of the remaining negatively charged CoO2 groups. Upon further removal of lithium x = 0.4 - 0.3 a strong deviation from the linear increase of the mean positron lifetime could be monitored, which can be attributed to the dissolution of CoO2 from the electrode.

98 Fri, 11:00 - 11:30: Coﬀee break

Fri, 11:30 - 13:00, HS 15.12

Fri, 11:30, Invited Self Assembly of Mesoporous Materials in the Gas-Phase: An in situ SAD Study Heinz Amenitsch1, Benedetta Marmiroli1, Fernando Cacho-Nerin1, Barbara Sartori1, Karin Jungnikl1, Ibrahimkutty Shyjumon2, Peter Laggner3, Michael Rappolt1

1Osterreichische¨ Akademie der Wissenschaft, Schmiedlstrasse 6, 8042 Graz, Austria 2Institute for Synchrotron Radiation, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany 3Bruker AXS GmbH, Oestliche Rheinbrueckenstrasse 49, 76187 Karlsruhe, Germany

Evaporation induced self assembly (EISA) provides an attractive method for the synthesis of mesostructured materials. A fast and economically interesting process for the production of mesostructured particles is the spray-drying process of aerosol droplets, in which the mesophase formation proceeds within a few seconds, but still, a high degree of control on the final mesostruc- ture is possible by applying suitable process parameters. Besides the chemical composition, also the external conditions influencing the evaporation rate (e.g. temperature, relative humidity) have been identified as key parameters for the resulting structure of the mesophase. Most of the previous studies have been performed on the dried aerosol and provided information on the effect of such parameters on the final structure or at the end of the evaporation chamber. For the in situ study, various setups were designed that enables the gas-phase measurements during the evaporation process. In an elongated evaporation vessel temperature gradients from a starting temperature (e.g. 5◦C) to final temperatures up to 400◦C can be applied within a few centimetres in the axial direction and provoke a fast evaporation of the volatile components of the ESIA process. X-ray measurements can be taken at steps along the temperature profile in the dryer tube and the self- assembly process can be followed with SWAXS. This presentation should give an overview of the different experiments starting from the ex-situ deposition, in situ experiments of mesoporous materials and finally hierarchical assembly of more complex structures.

99 Fri, 12:00 Mechanical properties of carbon nanostructures investigated by Monte Carlo simulations Markus Hartmann1, Melanie Todt2, David Holec1, Paul Mayrhofer1, Oskar Paris1, Franz Fischer1, Franz Rammerstorfer2 1Montanuniversit¨atLeoben, Franz-Josef-Straße 18, 8700 Leoben, Austria 2Vienna University of Technology, Gußhausstrasse 27-29, 1040 Vienna, Austria

Carbon nanostructures are a fascinating class of materials combining high stiffness with low weight and exceptional toughness that makes carbon a promising candidate for applications in structural mechanics. Understanding the mechanical behavior of carbon structures also on atomistic length scales is inevitable in describing the mechanical performance and stability of large, hierarchical structures like carbon onions and fibers. In the presented work ab initio calculations were used to extract classical potentials describing stretching, bending and torsion deformations of carbon bonds [1] that were used in subsequent Monte Carlo simulations to perform computational mechanical tests on graphene, carbon nanotubes and fullerenes. These tests included the application of hydrostatic pressure, the application of a ring load and the deformation of a fullerene between two plates. We analyzed the elastic response, as well as the stability limits and post- buckling behavior of the structures for different sizes. The simulation results were compared to the predictions of finite element methods to evaluate macroscopic parameters like elastic modulus or Poisson ratio of the investigated structures. In fullerenes special attention was paid to the influence of pentagons that are inherently present in these structures. It was observed that the pentagons deform less than the atomic bonds in hexagonal geometry. [1] Holec et al., Phys. Rev. B 81, 235403 (2010)

Fri, 12:15 Topologically nontrivial and nearly ﬂat bands in multi-orbital models Maria Daghofer1, Stefanos Kourtis1, J¨ornVenderbos1, Jeroen van den Brink1

1IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany

For topologically nontrivial and very narrow bands, Coulomb repulsion between electrons has been predicted to give rise to a spontaneous fractional quantum-Hall (FQH) state in absence of magnetic fields. We show that orbital degrees of freedom in frustrated lattice systems lead to a narrowing of topologically nontrivial bands for robust parameter ranges. We find that a strongly correlated t2g system on a triangular lattice can support a spin-chiral magnetic ordering pattern with such topologically nontrivial and flat bands. In order to go beyond mean field and to study the impact of longer-range interactions, we map the low-energy electronic states onto an effective one-band model. Exact diagonalization is then used to establish signatures of a spontaneous FQH state. [1] J. W. F. Venderbos, M. Daghofer and J. van den Brink, Phys. Rev. Lett. 107, 116401 (2011); J. W. F. Venderbos, S. Kourtis, J. van den Brink and M. Daghofer, Phys. Rev. Lett. 108, 126405(2012).

100 Fri, 12:30 Itinerant electrons in a 2-dimensional spin-ice system: Kondo-Lattice model on the checkerboard lattice J¨orn Venderbos1, Maria Daghofer1, Jeroen van den Brink1, Sanjeev Kumar2

1IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany 2IISER Mohali, Knowledge city, Sector 81, SAS Nagar, Manauli PO 140306, India

We investigated the theory of the interplay of itinerant electrons and localized magnetic moments on the frustrated checkerboard lattice as function of the super-exchange interaction between the localized moments and the band filling of fermions. We find that at half filling a very robust magnetic “flux” phase is lowest in energy. The ordering of the localized spins induces an effective gauge field flux of π for the electrons. Consequently, this phase preserves time-reversal symmetry and the low-energy effective theory of the electrons is that of massless Dirac fermions, resembling the situation in graphene except that the spin degree of freedom is absent here. The robustness of this state originates from the geometrical frustration of the checkerboard lattice. In the crossover regime from this flux state and the saturated FM state at vanishing super-exchange coupling, these Dirac fermions become massive with opposite sign of the mass at the two degeneracy points. This chiral spin state is then equivalent to a time-reversal breaking anomalous Quantum Hall phase, precisely in the way once envisioned by Haldane in graphene.

101 102 9 History of Physics (GEP) HS 05.01 (Physics Building)

History of Physics Geschichte der Physik Peter M. Schuster, [email protected]

Thursday, 20th September 2012, HS 05.01 13:00 - 14:00 Time Presenter Title Franz Serafin Exner – der Anfang des 13:00 - 13:20 Franz Sachslehner II. Physikalischen Institutes Karl Przibram (1878-1973) – Pionier 13:20 - 13:40 Wolfgang Reiter der nuklearen Festkörperphysik Graz physicists as agents of popular education. The role of physics in 13:40 - 14:00 Andreas Golob the Graz university-extension movement 1898-1938. 14:00 - 14:20 Coffee break

Thursday, 20th September 2012, HS 05.01 14:20 - 15:20 Time Presenter Title The stony cosmos of Andreas 14:20 - 14:40 Reinhard Folk Pleninger – Astronomy and Astrology in the 16th century Joseph Liesganig und die geodätische 14:40 - 15:00 Bruno Besser Vermessung zweier Meridianbögenin Osterreich-Ungarn¨ Eine “physikalische Reise” durch Wes- 15:00 - 15:20 Armand Kraml teuropa im Jahr 1838 15:20 - 15:40 Coffee break

Thursday, 20th September 2012, HS 05.01 15:40 - 16:20 Time Presenter Title Elektrisiermaschinen – Ein Streifzug 15:40 - 16:00 Franz Pichler an Hand des Schrifttums von 1600 bis 1800 Boltzmanns Bizykel – ein mechanis- 16:00 - 16:20 Heinz Krenn ches Analogon gekoppelter elektrischer Stromkreise

103 Thu, 13:00 - 14:00, HS 05.01

Thu, 13:00 Franz Seraﬁn Exner – der Anfang des II. Physikalischen Institutes Franz Sachslehner1 1Universit¨atWien, Strudlhofgasse 4, 1090 Wien, Austria

Franz Serafin Exner (1849 – 1926) folgt 1891 auf Josef Loschmidt als Vorstand des Physikalisch- Chemischen Institutes der UniversitätWien. Ihm gelingt es, mehr Raum und Personal zu erhalten und sein Institut allmählich besser zu versorgen. Nach dem Tod Josef Stefans (1893) wird versucht, Ludwig Boltzmann als Leiter des Physikalischen Instituts zu engagieren. Es tritt die Situation ein, dass im Physikalischen Institut niemand die experimentellen Praktika abhalten will, andererseits wurde im Physikalisch-Chemischen Institut nie wirklich physikalische Chemie gemacht. Exner übernimmt schließlich die Ausbildung in den experimentellen Praktika. So kommt es durch den Einfluss Ludwig Boltzmanns 1902 zur Neuordnung der physikalischen Institute, wobei Exn- ers Institut als II. Physikalisches Institut hervorgeht. Aufgrund des baufälligenHauses in der Türkenstraße 3 betreiben Exner, Boltzmann und Viktor v. Lang (sowie späterLechner) den Neubau fürdie physikalischen Institute in der Boltzmanngasse 5 (eröffnet1913). Exner wirkte auch bei der Planung des Radiuminstitutes mit (1910 eröffnet)und war dessen Kurator zeit seines Lebens. Wissenschaftlich war er sehr vielseitig. Seine wichtigsten Gebiete waren: Elektrochemie, Luftelek- trizität,Spektralanalyse und Farbenlehre. Er war auch ein Fördererder Erforschung der Radioak- tivität. Weiters gibt es interessante erkenntnistheoretischen Arbeiten. Exner war ein beliebter und erfolgreicher Lehrer. Namen wie Hans Benndorf, Stefan Meyer, Egon v. Schweidler, Eduard Haschek, Marian Smoluchowski, Erwin Schrödingerund andere zeugen davon. Die späterenNo- belpreisträgerVictor Franz Hess und Erwin Schrödingerwaren jahrelang Mitarbeiter Exners.

Thu, 13:20 Karl Przibram (1878-1973) – Pionier der nuklearen Festk¨orperphysik Wolfgang Reiter1

1Universit¨atWien, Spitalgasse 2-4, 1090 Wien, Austria

Vor den Hintergrund der Rolle des liberalen jüdischen Wiener Bürgertumsdes ausgehenden 19. und beginnenden 20. Jahrhunderts fürdie Förderungund Entwicklung von Wissenschaft und Kunst werden die wissenschaftlichen Leistungen von Karl Przibram und seiner Arbeitsgruppe am Institut fürRadiumforschung bis 1938 sowie dessen Wirken nach seiner Rückkehr aus dem belgis- chen Exil an der Universität Wien nach 1945 dargestellt.

104 Thu, 13:40 Graz physicists as agents of popular education. The role of physics in the Graz university-extension movement 1898-1938. Andreas Golob1 1Universit¨atGraz, Universit¨atsplatz3, 8010 Graz, Austria

When the idea(l)s of the university-extension movement reached Graz from Cambridge (1871) via Vienna (1895) in 1898, aspects of physics became regular topics of the so called “Volkstümliche Vorträge”,that is popular lectures. Numerous branches of the subject, like astronomy, experimental physics, geophysics and meteorology, were involved, links existed towards technical application, for example, the development of power stations, the electric grid and electric light was supported. On the other hand the dangers of this new energy source were illustrated by physicians. Rep- resentatives of the subject included less known local professors such as Leopold Pfaundler, Hans Benndorf and Heinrich Ficker von Feldhaus, but also some internationally renowned scientists like Victor F. Hess, Erwin Schrödingerand Alfred Wegener. The presentation, which is part of a work in progress on the local university-extension movement as a whole, will statistically show the contents of the relevant contributions and will demonstrate a handful of cases to show how knowledge was presented and which means, like pictures, films, experiments, were used to illustrate the talks. Correspondence with local organisers in and outside Graz can also highlight attitudes towards and, respectively, reactions of the audience and help to examine the impact of the lectures which should not only attract the educated bourgeoisie but also labourers and farmers, men and women alike. Early statistics will also shed some light on this question.

Thu, 14:00 - 14:20: Coﬀee break

105 Thu, 14:20 The stony cosmos of Andreas Pleninger – Astronomy and Astrology in the 16th century Reinhard Folk1 1Johannes Kepler University Linz, Altenberger Straße 69, 4040 Linz, Austria

In the years 1590 to 1607 six stony tables under the tile “Calendarium Perpetuum” were created by Andreas Pleninger. They demonstrate the topological order at that time. In particular on three of this tables (on the tables in the monastery Chremsminster, in the historical museum in Regensburg and in the museum in Kassel) one finds an astrolabe, on two of them a horoscope and on one the starmaps of the northern and southern celestial sphere. The sources of this artworks and their relation to the cosmic conceptions of that time will be discussed. [1] P. Altman Pötsch, Der ewigwährendeKalender im astronomischen Kabinett der Sternwarte genannt “Astronomischer Tisch”, Offentliches¨ Stiftsgymnasium Kremsmünster.154. Jahresbericht, Thalheim. 2011 [2] P. Altman Pötsch und R. Folk, Der astronomische Tisch des Andreas Pleninger aus dem Jahr 1603, eingereicht in: “Anzeiger des Germanischen Nationalmuseums” [3] R. Folk, Das Astrolabium am Kalendertisch im Historischen Museum in Regensburg

Thu, 14:40 Joseph Liesganig und die geod¨atische Vermessung zweier Meridianb¨ogenin Osterreich-Ungarn¨ Bruno Besser1 1IWF, Schmiedlstrasse 6, 8042 Graz, Austria

Joseph Liesganig, 1719 in Graz geboren, studierte ab 1734 Mathematik, Physik und Astronomie an der Grazer Jesuitenuniversität.Daran anschließend studierte er Theologie an der Jesuitenuni- versitätWien und wurde 1749 Prediger in Komarno (damals Ungarn, heute Slowakei). Nach einem einjährigenAufenthalt als Mathematikprofessor am Jesuitenkolleg in Kaschau (heute Kosice, Slowakei) kehrte er 1752 als Mathematikprofessor an das Wiener Kolleg zurück und wurde auch verantwortlich fürdie dortige Jesuitensternwarte (unter der Führungvon Maximilian Hell). Nach der Auflösungdes Jesuitenordens im Jahr 1773 verließ Liesganig Wien und wurde Direktor der staatlichen Vermessung fürGalizien und Lodomerien in Lemberg (heute Lwiw, Ukraine), wo er auch 1799 starb. Bereits 1761/2 wurde Liesganig von Erzherzogin Maria Theresia mit der Vermes- sung eines Meridians in Osterreich-Ungarn¨ beauftragt, woraufhin er den Meridian von Brünn(heute Brno, Tschechien) bis Warasdin (heute Varazdin, Kroatien) auswählteund mit Hilfe eines Trian- gulationsnetzes ausmaß. Fürdiese Arbeiten wurde je eine Basislinie im Marchfeld und zwischen Wiener Neustadt und Neunkirchen eingemessen. Die Arbeiten an der Meridianmessung brachten ihn auch wieder in seine steirische Heimat und 1767 waren die Arbeiten abgeschlossen. In den darauffolgenden zwei Jahren vermaß Liesganig auch einen Meridianbogen in Ungarn, zwischen Kistelek und Czurok (heute Curug, Serbien).

106 Thu, 15:00 Eine “physikalische Reise” durch Westeuropa im Jahr 1838 Armand Kraml1 1Sternwarte Kremsmünster,Stift Kremsmünster,4550 Kremsmünster,Austria

Im Sommer 1838 unternahmen drei österreichische Physiker eine wissenschaftliche Reise durch halb Europa. Die Reisegesellschaft setzte sich zusammen aus August Kunzek (1795-1865), damals Professor fürPhysik in Lemberg, Andreas von Ettingshausen (1796-1878), Professor fürPhysik an der UniversitätWien und P. Marian Koller (1792-1866), Direktor der Sternwarte Kremsmünster. Aus Kollers Aufzeichnungen soll diese Reise fürdie Geschichte der Physik jener Zeit ausgewertet werden. Die Reise ging über Prag nach Berlin, Hamburg und Altona, dann per Schiff nach Lon- don. Von dort begab man sich nach Paris und Brüssel. Am Schluss stand die Teilnahme an der Versammlung der Deutschen Arzte¨ und Naturforscher, die in diesem Jahr in Freiburg im Breis- gau abgehalten wurde. Uber¨ München ging es dann wieder nach Hause. Im Vordergrund standen vor allem Besuche der Sternwarten sowie physikalischer Werkstättenund Laboratorien. Mit der Darstellung dieser Reise wird gleichsam ein Schnappschuss auf die aktuellsten Arbeitsbereiche von astronomischer und physikalischer Forschung im Jahr 1838 gemacht. Dieser Begriff aus der Fo- tografie bietet sich besonders an, da gerade junge Technologie auf die drei Reisenden damals eine besondere Anziehungskraft ausübte.

Thu, 15:20 - 15:40: Coﬀee break

107 Thu, 15:40 Elektrisiermaschinen - Ein Streifzug an Hand des Schrifttums von 1600 bis 1800 Franz Pichler1 1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria

Der Vortrag zeigt in einer Bilderfolge anhand von im Original vorliegenden Büchern die verschiedenen Konstruktionen und Bauformen von Reibungselektrisiermaschinen, wie diese vom Physi- ker, Instrumentenmacher und Schausteller im Zeitraum von 1600 bis 1800 behandelt wurden. 1600 markiert das Jahr, in dem der englische Arzt und Wissenschaftler William Gilbert sein Werk “De Magnete” veröffentlichte, in dem zum erstenmal “Elektrizität”vorkommt. Das Jahr 1800 zeigt die Entdeckung des galvanischen Elementes durch Alessandro Volta an, eine Entdeckung, die fürdie Physik eine neue Orientierung in der Erforschung der Elektrizitätermöglichte. Wenn auch heute Reibungselektrisiermaschinen der vorgestellten Art keine große Bedeutung mehr haben, so haben deren Entwicklung und die daran durchgeführtenExperimente dennoch einen wichtigen Beitrag zur Erforschung des physikalischen Phänomensder Elektrizitätbeigetragen.

Thu, 16:00 Boltzmanns Bizykel – ein mechanisches Analogon gekoppelter elektrischer Stromkreise Heinz Krenn1 1Universit¨atGraz, Universit¨atsplatz5, 8010 Graz, Austria

Hermann Helmholtz hatte den Begriff der “zyklischen Bewegung” fürstationäreVorgängein die klassische Mechanik eingeführt,womit er den Zustand einer Bewegung ohne sichtbare äußere Veränderungbeschrieb: Die bewegten Massenpunkte eines rotierenden Körpers werden ständig durch zyklische Bewegung ersetzt, sodass der Körper keine geometrische Veränderung– außer eine Rotation - erfährt. Dies gilt nicht nur fürstationärfließende Strömungen, sondern auch fürdie fließende Elektrizität,den elektrischen Strom. Ludwig Boltzmann hat das Helmholtz’sche Monozykel, das derartige zyklische Bewegungen beschreibt, auf das sogenannte Bizykel erweitert, einem mechanischen Apparat mit zwei gekoppelten Monozykeln. Ein ausgeklügelterMechanismus beschreibt die Vorgängegekoppelter Bewegungen und ist ein perfektes Analogon fürgekoppelte elektrische Stromkreise, wie z.B. einem elektrischen Transformator. In Ermangelung geeigneter elektronischer Aufzeichnungsgeräte(wie z.B. einem Elektronenstrahl-Oszilloskop) stellte das Boltz- mannsche Bizykel ein hervorragendes Demonstrationsobjekt dar, um elektrische Vorgängezu veran- schaulichen. Die Konstruktion des Bizykel verdeutlicht die hohe Kompetenz von Ludwig Boltzmann als hervorragenden Experimentalphysiker, was selbst in Fachkreisen zu wenig gewürdigtwurde.

108 10 Medical, Bio and Environmental Physics (MBU) SR 15.15

Medical, Bio and Environmental Physics Medizinische Physik, Biophysik und Umweltphysik G¨unther Schauberger, [email protected]

Thursday, 20th September 2012, SR 15.15 14:30 - 15:30 Time Presenter Title 14:30 - 14:40 Günther Schauberger Opening of the Topical Session MBU Monitoring of Radiation Exposure in 14:40 - 15:00 Christina Hofstätter the European Columbus Laboratory of the International Space Station (Multiawesome) Multispectral Multi- 15:00 - 15:20 Otto Scheibelhofer probe Monitoring 15:30 - 15:50 Coffee break

Thursday, 20th September 2012, SR 15.15 15:50 - 16:30 Time Presenter Title 100-year record of 236-U/238-U in 15:50 - 16:10 Stephan Winkler coral as a step towards establishing 236-U as oceanic tracer Stalk-free membrane fusion of cationic 16:10 - 16:30 Georg Pabst lipids via an interdigitated phase

109 Thursday, 20th September 2012, SR 15.15 5-minute Poster Presentations† 16:30 - 17:00 Time Poster-ID Presenter Title Review and Cross- comparison of Matroshka Phantom Measurements in 16:30 - 16:35 POS-45† Christina Hofstätter Different Compartments of the International Space Station Bioequivalent Solid-State 16:35 - 16:40 POS-44† Michael Hajek Dosimetry: Current Trends and Future Developments Korrelation relativer Feuchte und Strom- 16:40 - 16:45 POS-46† Maryam Nikbakhti umwandlungskoeffizient der Dünnschicht-Photovoltaik Ground based MAX-DOAS observations of tropospheric 16:45 - 16:50 POS-43† Carlos Armando Alberti trace gases in San Salvador, El Salvador 17:00 Wahl des Vorsitzenden des Fachausschusses MBU †Please find the corresponding abstracts in the poster section of this book by looking up the Poster-ID

Thu, 14:40 - 15:30, SR 15.15

110 Thu, 14:40 Monitoring of Radiation Exposure in the European Columbus Laboratory of the International Space Station Christina Hofstätter1, Michael Hajek1, Thomas Berger2, Christine Körner2, Günther Reitz2

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria 2German Aerospace Center, Linder H¨ohe,51147 K¨oln,Germany

Cosmic radiation and its secondaries created in interactions with spacecraft shielding structures constitute one of the most important hazards associated with human spaceflight. Crewmembers are facing exposures to radiation qualities that are known to produce distinct biological damage compared with radiation on ground, and dose levels that may easily exceed those routinely received by terrestrial radiation workers. DOSIS is a comprehensive and overarching international dosimetry programme coordinated by the German Aerospace Centre, supporting assessment of potential biological implications on the health of space crew. It maps the distribution of the radiation environment in the European Columbus laboratory of the International Space Station (ISS) using a comprehensive set of active and passive instrumentation to account for the cosmic-ray charge and energy spectrum. Passive detector packages accommodating luminescence and plastic nuclear track detectors (PNTD) measured absorbed dose and linear energy transfer (LET) spectra at eleven sites throughout Columbus for mission durations of 135 days (July to November 2009) and 191 days (November 2009 to May 2010). Discussion focuses on thermoluminescence dosimetry (TLD) results but strives exemplary the convolution of TLD and PNTD data to derive dose equivalent and evaluate the significance of the high-LET (≥ 10 keV/µm) contribution to the TLD dose. The absorbed dose distribution determined by different luminescence phosphors showed a high degree of consistency and a distinct spatial pattern with variations of up to 22% between the sites. The decreased dose rate observed for the second mission is attributed to increasing solar activity and ISS altitude changes.

Thu, 15:00 (Multiawesome) Multispectral Multiprobe Monitoring Otto Scheibelhofer1, Roland Hohl1, Stefan Sacher1, Jos´eMenezes1, Johannes Khinast1,2

1Research Center Pharmaceutical Engineering GmbH, Inﬀeldgasse 21a, 8010 Graz, Austria 2Graz University of Technology, Inﬀeldgasse 21a, 8010 Graz, Austria

In the food and pharmaceutical industry, near-infrared spectroscopy is a more and more frequently used tool for process monitoring. This is motivated by its fast and non-invasive nature. Further on, no extensive sample preparation is needed, enabling the use as an online process analytical tool. However, this comes with the drawback of large amounts of correlated data, often influenced by many external factors. Therefore, a lot of effort has to be invested in the correct use of mathematical tools to extract the information of interest. Here we put to use a new prototype NIR spectrometer (by EVK, Raaba, Austria), based on an established chemical imaging system, to enable the reading of several attached probes at the same time. However, even when investigating the same sample, there are slight differences from one probe to another. On the one hand, this is caused by their different field of view; on the other hand, these are to be avoided disturbances, on nominally similar probes. Therefore, it is necessary to identify these disturbances and consider them in the spectral interpretation. This should allow the monitoring of processes at different positions, as well as the simultaneous monitoring of different processes, with one measurement system. In this work, data from the prototype system are presented in use on a pharmaceutical process. It is shown how to overcome some of the appearing difficulties when dealing with a multiprobe system, in order to enable fast and robust process monitoring, and render process control.

111 Thu, 15:30 - 15:50: Coﬀee break

Thu, 15:50 - 16:30, SR 15.15

Thu, 15:50 100-year record of 236-U/238-U in coral as a step towards establishing 236-U as oceanic tracer Stephan Winkler1, Peter Steier1, Jessica Carilli2

1University of Vienna, W¨ahringerStraße 17, 1090 Vienna, Austria 2Australian Nuclear Science and Technology Organization, Lucas Heights, New South Wales 2234, Australia

Since uranium is known to behave conservatively in ocean waters, 236-U has great potential in application as oceanic tracer. 236-U (t1/2=23.4Ma) was introduced into the oceans by atmospheric nuclear weapon testing with amounts estimates ranging from 700kg to 1500kg. Thus a resulting initial average 236-U/238-U ratio of at least 5e-9 is expected for an oceanic mixed layer depth of 100m. This ratio is signiﬁcantly higher than the natural pre-nuclear age background, which is expected to be at 1e-14 levels. However, even the elevated ratios of global stratospheric fall-out are beyond the capabilities of ICPMS and TIMS methods. However, the exceptional sensitivity and ultra-low background for 236-U of the Vienna Environmental Research Accelerators Accelerator Mass Spectrometry system allows us to measure down to 1e-13 detection limits. We present a year-by-year record of 236-U/238-U for a Caribbean coral core covering years 1944 to 2006, thus allowing to us put constraints on the oceanic input of 236-U by atmospheric testing. Moreover modelling of the results also demonstrates the capabilities of 236-U as oceanic tracer.

112 Thu, 16:10 Stalk-free membrane fusion of cationic lipids via an interdigitated phase Georg Pabst1, Caroline Lonez2, Michel Vandenbranden2, Jacques Jestin3, Aurel Radulescu4, Jean-Marie Ruysschaert2, Thomas Gutberlet5

1Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria 2Faculte des Sciences, Universite Libre de Bruxelles, CP 206/2, Campus Plaine, Blvd. du Triomphe, 1050 Brussels, Belgium 3Laboratoire Leon Brillouin, CEA/CNRS, C.E.A Saclay, 91191 Gif-sur- Yvette Cedex, France 4J¨ulichCentre for Neutron Science, Lichtenbergstrasse 1, 85747 Garching, Germany 5Helmholtz-Zentrum Berlin GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

Packaging of DNA is a central concept in gene therapy in order to overcome membrane barriers. One possibility is to use cationic lipids, which may form various aggregate structures when complexed with DNA, due to an intricate interplay of electrostatic interactions (see e.g.[1]). One highly promising lipid candidate is N-t-butyl-N’-tetradecyl-3-tetradecylaminopropionamidine (diC14-amidine), which shows high fusion capabilities with target membranes. Interestingly and in contrast to other lipids, fusion of diC14-amidine vesicles is significantly enhanced in the gel phase. Therefore, we have performed a comprehensive X-ray and neutron small-angle scattering as well as dilatometry and ultrasound velocimetry study on diC14-amidine. We found an anomalously thin lamellar fluid phase at high temperatures, which transforms into a loosely packed interdigitated phase below the chain melting transition. Typical fusion pathways via point-like defects (stalks) can therefore be ruled out in order to explain amidine’s unusual fusion behavior. Instead, we propose that the loose lipid packing leads to a significant exposure of the hydrophobic lipid core to the aqueous phase, reducing energy penalties from the removal of water during fusion. [1] A.V. Radhakrishnan, S. K. Ghosh, G. Pabst, V. A. Raghunathan, and A. K. Sood, Proc. Natl. Acad. Sci. 109: 6394 - 6398 (2012). [2] G. Pabst, C. Lonez, M. Vandenbranden, J. Jestin, A. Radulescu, J.-M. Ruysschaert, and T. Gutberlet, Soft Matter, (2012), DOI: 10.1039/c2sm25665g.

113 114 11 Surfaces, Interfaces and Thin Films (OGD) HS 15.02

Surfaces, Interfaces and Thin Films Oberflächen, Grenzflächen und dünneSchichten Christian Teichert, [email protected]

Thursday, 20th September 2012, HS 15.02 09:00 - 11:00 Time Presenter Title Surface Phases on 122 Fe Based Super- 09:00 - 09:20 Erminald Bertel conductors: An Indication of Charge Density Wave Fluctuations? Scanning Tunneling Microscopy study 09:20 - 09:40 Bernhard St¨oger of single-crystalline Sr3Ru2O7 Paper - A Material with Unique Prop- 09:40 - 10:20 Robert Schennach erties Understanding the electronic structure 10:20 - 10:40 Matus Milko of weakly bound nanohybrid systems Reliably Modeling the Properties of 10:40 - 11:00 David Egger a Complex Inorganic-Organic Hybrid System 11:00 - 11:30 Coﬀee break

Thursday, 20th September 2012, HS 15.02 14:30 - 15:30 Time Presenter Title Growth of ZnO nano-rods solar-cell 14:30 - 14:50 Marcus Rennhofer material on ITO investigated by X- Ray-diffraction Tip-enhanced Raman Spectroscopy – 14:50 - 15:10 Franz Schmied challenges and opportunities New advanced microscopic methods 15:10 - 15:30 Herbert Reingruber for detailed analysis of strong asymmetric microfiltration membranes 15:30 - 15:50 Coffee break

115 Thursday, 20th September 2012, HS 15.02 15:50 - 18:00 Time Presenter Title UHV Helium Ion Microscopy – a new 15:50 - 16:20 Gregor Hlawacek tool for surface science? Deposition of Metal Clusters Formed 16:20 - 16:40 Alexander Volk Inside Superfluid Helium Nanodroplets A novel two-dimensional Cu-tungstate 16:40 - 17:00 Martin Denk (CuWOx) phase on Cu(110) Organic PCBM field effect transistors: Analysis of the contact properties by 17:00 - 17:20 Mandy Grobosch combined photoemission spectroscopy and electrical measurements Surface Induced Crystal Structures: 17:20 - 17:40 Roland Resel Crystal Growth and Structure Solu- tion The electronic structure of pentacene 17:40 - 18:00 Daniel Lüftner monolayers on Ag(110) and Cu(110)

Friday, 21st September 2012, HS 15.02 09:00 - 11:00 Time Presenter Title ZrO ultra-thin films on Pd Zr(0001): 09:00 - 09:20 Joongil Jake Choi 2 3 Structure and growth of metal clusters AFM based electrical investigations on 09:20 - 09:40 Markus Kratzer Ge nanodomes on Si(001) In situ observation of the growth of 09:40 - 10:20 Tomáˇs Sikolaˇ germanium nanofibres Ordered Array of Single Au Adatoms 10:20 - 10:40 Zbynek Novotny on Fe3O4(001) with Remarkable Ther- mal Stability Strain and structure driven complex 10:40 - 11:00 Josef Redinger magnetic ordering of a CoO overlayer on Ir(100) 11:00 - 11:30 Coffee break

116 Friday, 21st September 2012, HS 15.02 11:30 - 13:40 Time Presenter Title Microscopy and Spectroscopy of ultra- 11:30 - 12:10 Peter Zeppenfeld thin organic layers and nanocrystals Cs doping of organic semiconducting monolayers: probing the electronic 12:10 - 12:30 Eva Reinisch and geometric structure with angle resolved UPS The influence of venting on the is- 12:30 - 12:50 Levent Tümbek land size distribution observed for Hexaphenyl on mica Growth and structure of Tetraphenyl- 12:50 - 13:10 Margareta Wagner porphyrin on Cu(110)-p(2x1)O STM Studies of Surface-Supported 13:10 - 13:40 Stefan Müllegger Stable Hydrocarbon Radicals

117 Thu, 09:00 - 11:00, HS 15.02

Thu, 09:00 Surface Phases on 122 Fe Based Superconductors: An Indication of Charge Density Wave Fluctuations? Erminald Bertel1, Michael Cordin1, Peter Amann2, Alexander Menzel1, Mikhail Baranov1, Sebastian Diehl1, Josef Redinger3, Cesare Franchini4

1University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria 2Vorarlberg University of Applied Sciences, Hochschulstrasse 1, 6850 Dornbirn, Austria 3Vienna University of Technology, Gußhausstrasse 25-25a, 1040 Vienna, Austria 4University of Vienna, Sensengasse 8/12, 1090 Vienna, Austria

On the cleavage planes of 122 Fe based superconductors two different long-range ordered√ struc-√ tures can be found, i.e. a (2 × 1) phase prevalent after cleavage at low temperature and a 2 × 2 phase found after cleavage at room temperature. The majority of groups attributes these structures to an adlayer of earth alkali metal atoms. The existence of different long-range ordered structures corresponding to the same coverage in different temperature regimes is extremely rare in surface systems and requires an active role of the substrate in the ordering process. The adsorbate system Br/Pt(110) exhibits analogous phases, namely a (2 × 1)4-Br/Pt(110) structure at T < 50 K and a c(2 × 2)-Br/Pt(110) structure at room temperature. The phase transition is associated with the removal of a periodic lattice distortion (PLD) and an accompanying charge density wave (CDW) in the substrate as T is increased. At sufficiently low temperature the fluctuating CDW/PLD order parameter is stabilised by the adsorbate in a lock-in type mechanism. A similar mechanism can account for the observations on the 122 Fe pnictide surfaces suggesting the presence of CDW fluctuations at low temperature.

Thu, 09:20 Scanning Tunneling Microscopy study of single-crystalline Sr3Ru2O7 Bernhard St¨oger1, Zhiming Wang1, Marcel Hieckel1,2, Florian Mittendorfer1, Raimund Podloucky2, Josef Redinger1, David Fobes3, Zhiqiang Mao3, Michael Schmid1, Ulrike Diebold1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria 2University of Vienna, Sensengasse 8/7, 1090 Vienna, Austria 3Tulane University, 2001 Percival Stern Hall, 6400 Freret St, New Orleans, LA, USA

Perovskite oxides play an important role as cathodes in solid oxide fuel cells (SOFC) and in catalysis. Investigating surface defects such as oxygen vacancies and the adsorption of relevant molecules helps gaining more insight into the physics behind SOFCs and catalytic processes. High- quality Sr3Ru2O7 (SRO) single crystals were grown using the ﬂoating zone technique. The SRO samples were cleaved at 150 K under UHV conditions and subsequently investigated by STM at 78 K and 6 K. To determine which species are imaged in STM, doped SRO samples were investigated and STM simulations were performed. Furthermore, we have characterized the defects that are present at the as-cleaved surfaces, and how reactive they are if exposed to CO and O2. STM shows that CO binds to some defects at the surface and, possibly, also to apical oxygen atoms at the perfect surface. The interaction between the clean surface and CO was also investigated by DFT calculations. This work was supported by the Austrian Science Fund (FWF project F45).

118 Thu, 09:40, Keynote Paper - A Material with Unique Properties Robert Schennach1 1Graz University of Technology, Petersgasse 16/2, 8010 Graz, Austria

Paper is one of the oldest man made materials, which one is using on a daily basis for things like writing, printing, wrapping or carrying goods. However, one hardly stops to think about this quite unique material. Paper has several unique properties due to its very hierarchical structure from the cellulose molecules via the paper fibers up to the paper network. The current view of the surface structure and surface chemistry of paper fibers will be presented, which play an important role in the formation of the bonds between the individual fibers in the paper network. The nature of the fiber - fiber bond in paper is still under discussion, but researchers agree that mechanical interlocking, inter diffusion, hydrogen bonds, Van der Waals bonds and Coulomb interactions do play a role. However, it is not yet clear to which extend these bonding forces play a role in paper strength. In addition, the influence of capillary bridges will be discussed. While it is agreed that they play an important role during bond formation (as paper is simply made by spraying a suspension of paper fibers in water on a sieve and then drying the sheet of paper), it is an open question whether or not capillary bridges still play a role in dry paper. Recent experimental results concerning this questions will be discussed.

Thu, 10:20 Understanding the electronic structure of weakly bound nanohybrid systems Matus Milko1, Claudia Draxl2, Peter Puschnig1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2Humboldt-Universit¨atzu Berlin, Newtonstraße 15, 12489 Berlin, Germany

We present an ab initio study on the formation of electronic states at the interface in weakly bound hybrid nanostructures. As an example, we study the polymer poly-para-phenylene embedded in a zig-zag nanotube, for which we vary the diameter up to the limiting case of graphene. It turns out, that besides the anticipated electronic level alignment with respect to the vacuum potential, three additional factors impact the electronic structure of the combined system. First, we observe a diﬀerence in the electrostatic potential outside and inside the nanotube, which is associated with its curvature. Second, an interface dipole arises from the charge redistribution within the sub-units. Finally, mutual polarization eﬀects of the polymer and its host are shown to play an important role in the level alignment. We investigate in detail, how these three factors depend on size and spatial arrangement of the constituents, and the fact whether the nanotube is metallic or semiconducting. Based on this knowledge, we propose a simple scheme to predict the nanohybrid’s electronic structure from the bands of its constituents alone.

119 Thu, 10:40 Reliably Modeling the Properties of a Complex Inorganic-Organic Hybrid System David Egger1, Victor Ruiz2, Wissam Al-Saidi3, Tomas Bucko4, Alexandre Tkatchenko2, Egbert Zojer1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany 3University of Pittsburgh, Pennsylvania 15261, USA 4Comenius University, mlymska dolina, 84215 Bratislaba, Slovakia

When different materials align to form hetero-structures, the final electronic properties are often determined by the connecting interface. In nowadays organic-electronic devices, where several semiconductor/metal and semiconductor/semiconductor interfaces are an integral part of common device geometries, controlling these interfaces is not only necessary to maintain device functionality, but might even be exploited towards designing electronic features from the bottom-up. In this presentation, we seek for a microscopic insight into these interfaces and the relevant physical and chemical processes. A prototypical metal-supported organic double-layer system – copper phtalo- cyanine (CuPc) on 3,4,9,10-perylene tetracarboxylic dian-hydride (PTCDA) adsorbed on Ag(111) – is investigated by means of semilocal density-functional theory (DFT) based band-structure compu- tations. Including van der Waals (vdW) interactions through PBE+vdWsurf, a recently developed scheme where dispersion-corrected DFT is combined with the Lifshitz-Zaremba-Kohn theory to account for the polarizability within the metallic surface [Phys. Rev. Lett. 108, 146103 (2012)], we underline the importance of dispersive interactions and physisorptive bonding at the interfaces in CuPc@PTCDA@Ag(111). Comparing our results to recent experimental data [Phys. Rev. Lett. 108, 106103 (2012)], we find very good agreement for adsorption distances and CuPc-induced shifts in the electronic structure of the PTCDA/Ag(111) interface. These findings are rationalized by vdW-interactions, thus highlighting their consideration as being imperative for a microscopic understanding and quantitatively accurate modeling of interfaces in complex metal-organic systems.

Thu, 11:00 - 11:30: Coﬀee break

120 Thu, 14:30 - 15:30, HS 15.02

Thu, 14:30 Growth of ZnO nano-rods solar-cell material on ITO investigated by X-Ray-diffraction Marcus Rennhofer1, Herwig Peterlik1, Johanna Akbarzadeh1, Erhard Schafler1, Stephan Abermann2, Antun Peić2, Theodorus Dimopoulos2, Hubert Brueckl2

1University of Vienna, Strudlhofgase 4, 1090 Vienna, Austria 2Austrian Institute of Technoloy, Donau-City-Strasse 1, 1220 Vienna, Austria

ZnO is a wide bandgap (∼3.2 eV) semiconductor, crystallizing in the hexagonal wurtzite form. It is natively n-type doped and possesses favorable properties such as high transparency, high electron mobility and strong room temperature-luminescence. In the last years great interest was attracted towards ZnO nanostructures such as nanorods (NR). ZnO NR arrays have been investigated for various applications in a number of emerging areas one of them solar cells. This work focuses on the controlled electrochemical growth of ZnO NRs on Sn-doped In2O3 (ITO)-coated glass substrates. The structural development of NRs on the initial stages of growth was analyzed by different XRD techniques. The formation of the crystalline ZnO-structure could be measured using WAXS-geometry. The WAXS measurements show that ZnO-structure peaks of the ZnO-NR on the ITO substrate occur for deposition times longer than 1 min. Peaks of the directions (100), (002), (101), (102) and (110) could be identified. The formation of the (002) peak – being the favorable direction for producing well aligned ZnO-NR – is the strongest pronounced. The formation of the single peaks is linear in time. There was no shielding of the ITO peaks visible. The FWHM of all peaks was nearly stable for all deposition steps as was the position of the peaks. The results imply that the use of preparation techniques known from chemical industry and industrial scale allow to manufacture cheap and efficient solar cells.

Thu, 14:50 Tip-enhanced Raman Spectroscopy – challenges and opportunities Franz Schmied1,2, Tatiana Perova1, Silvia Giordani1, Paula Colavita1, Robert Schennach2,3

1University of Dublin, Trinity College Dublin, College Green, Dublin 2, Ireland 2CD-Laboratory for Surface Chemical and Physical Fundamentals of Paper Strength, Graz University of Technology, Petersgasse 16/2, 8010 Graz, Austria 3Institute of Solid State Physics, Graz University of Technology, Petersgasse 16/2, 8010 Graz, Austria

Tip-enhanced Raman Spectroscopy (TERS) is a new technique that combines the scanning capabilities of atomic force microscopy (AFM) with Raman spectroscopy on the nanometer scale. Here, a metal-coated AFM tip acts as nanoantenna, which enhances the weak Raman signal of the Near Field by orders of magnitude and allows for overcoming the optical diffraction limit. A crucial role in reaching optical resolution down to 10nm plays the nanoantenna. Here, we present techniques (vapor-coated, electroless chemical deposition) to metal-coated commercially available AFM probes suitable for TERS measurements on opaque samples in upright configuration. Fur- ther, we address interpretation of signal “blinking” in TERS spectra that belongs to carbonaceous contamination and live-time issues of the used coating. The financial support of Mondi, Science Foundation Ireland, and the Austrian Federal Ministry of Economy, Family and Youth and the National Foundation for Research, Technology and Development is gratefully acknowledged.

121 Thu, 15:10 New advanced microscopic methods for detailed analysis of strong asymmetric microﬁltration membranes Herbert Reingruber1, Armin Zankel1, Peter P¨olt1

1Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria

Filtration is a very essential technology in various fields of science. Concerning the water shortage of many countries the importance of filtration technology gets clear. For many of these applications microfiltration membranes are used. Modern filtration membranes are high tech products delivering high flux rates compared with well defined retention properties, due to their special asymmetric pore structure. For membrane optimization new techniques of characterizing them are essential. This work shows the development and results of two new characterization methods based on electron microscopic methods. One method allows a three dimensional (3D) reconstruction of the membrane structure. This was accomplished by automated serial sectioning and subsequent imaging of the membrane cross-section. The achieved image stack was used for 3D reconstructions. From the reconstruction, parameters like the inner membrane surface, the local porosity or by means of fluid simulations the water was flux calculated. The obtained data are in agreement with experimental data. However the properties of the pore walls (whether they are hydrophilic or hydrophobic) cannot be measured with this method. Therefore the microscopic membrane structure was studied additionally under wet conditions. For this aim the microscope sample chamber can be used as micro- laboratory in order to establish “environmental” conditions. By cooling of the membrane water can condensate and the interaction of the pores with water can be observed. The number and size distribution of wet and dry pores during such a wet- drying experiment can be obtained.

Thu, 15:30 - 15:50: Coﬀee break

122 Thu, 15:50 - 18:00, HS 15.02

Thu, 15:50, Invited UHV Helium Ion Microscopy – a new tool for surface science? Gregor Hlawacek1, Vasilisa Veligura1, Raoul van Gastel1, Harold Zandvliet1, Bene Poelsema1

1University of Twente, Carr´eCR 2.213, P.O. Box 217, 7500 AE Enschede, Netherlands

Helium Ion Microscopy (HIM) is a new tool that allows high resolution imaging of a wide range of materials. The fact that the technique is not limited to conductive materials and the many different contrast mechanisms make it a promising tool for nano structure research. HIM has demonstrated unprecedented resolution both on conductive and isolating materials. It is well- known for its high surface sensitivity when using secondary electrons generated by the impinging ions. Chemical sensitivity is possible via the backscattered He. Both qualitative element contrast maps as well as quantitative localized Rutherford Backscattering are possible. In addition Ionolu- minescence allows to obtain information on the bandstructure and defects, such as color centers, by analyzing the emitted photons. The extension of the method to UHV conditions and the high surface sensitivity allow to investigate surface and interface properties with a high spatial resolution. Investigated systems of interest to surface science include self assembled monolayers and thin films of conjugated molecules. However, I will also show results on the visualization of buried interfaces and demonstrate how crystallographic information can be obtained. In all cases the relevant contrast mechanisms will be discussed. This research is supported by the Dutch Technology Foundation STW, which is the applied science division of NWO, and the Technology Programme of the Ministry of Economic Affairs.

Thu, 16:20 Deposition of Metal Clusters Formed Inside Superﬂuid Helium Nanodroplets Alexander Volk1, Markus Koch1, Evelin Fisslthaler2, Werner Grogger2, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Graz University of Technology, Steyrergasse 17/III, 8010 Graz, Austria

We have recently successfully synthesized silver (Agn) and chromium (Crn) nanoclusters inside superfluid helium nanodroplets (Hen) and deposited these metal clusters on an amorphous carbon (a-C) surface. Transmission electron microscope (TEM) images shall be presented as well as microbalance measurements. During the past decade, Hen turned out to offer a unique experimental environment, combining both a least perturbing superfluid quantum matrix at 0.4 K and a well defined local confinement, given by the droplet radius of a few nanometres. Therefore these nanocryostats are well suited for the synthesis of metal nanoclusters. The first surface deposition of nanoclusters (Agn) assembled inside Hen has only recently been demonstrated [1]. We were now able to deposit Crn using the same method. The comparison of Agn and Crn measurements indicates a strong oxidation of Crn, while this is not the case for Agn. In the next step we want to form bimetallic core shell structures in Hen by sequential particle pickup. Due to the formation process in the favourable superfluid environment, we expect a radial symmetric structure of these bimetallic nanostructures, where a shell of silver atoms encloses and therefore passivates the chromium core. Besides the TEM images and microbalance investigations, we seek to present more detailed chemical information obtained from X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX) and electron energy loss spectrometry (EELS) measurements. [1] E. Loginov, L. F. Gomez, and A. F. Vilesov; J. Phys. Chem. A 115, 7199-7204 (2011)

123 Thu, 16:40 A novel two-dimensional Cu-tungstate (CuWOx) phase on Cu(110) Martin Denk1, David Kuhness1, Margareta Wagner1, Svetlozar Surnev1, Fabio Negreiros2, Luca Sementa2, Giovanni Barcaro2, Alessandro Fortunelli2, Falko Netzer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, I-56124, Pisa, Italy

We explore the feasibility to fabricate W-oxide nanostructures on metal surfaces via self- assembly and condensation of (WO3)3 clusters, deposited directly from the gas phase: here we report the formation of a novel two-dimensional Cu-tungstate CuWOx phase on Cu(110). A beam ◦ of (WO3)3 cluster molecules, formed by sublimation of WO3 powder at ∼900-1000 C in a thermal evaporator, has been directed onto a Cu(110)2×1-O surface oxide at low temperature and the surface has been annealed subsequently at 600 K. At low temperature (<15 K) the (WO3)3 clusters adsorb in intact molecular form, albeit in a somewhat distorted cluster geometry. Upon heating to 600K, the (WO3)3 molecules dissociate and react with the Cu-O(2×1) surface oxide, forming a wetting monolayer with a well ordered incommensurate structure. The latter has been structurally characterized by high-resolution STM imaging and LEED. The chemical nature and electronic structure of this novel 2-D W-O-Cu layer has been investigated by high-resolution XPS core level spectroscopy, NEXAFS, and valence band spectra. The unusually sharp W 4f core level spectra, the speciﬁc NEXAFS ﬁngerprint and the evolution of the valence band all suggest that this 2-D W surface oxide is of a Cu-tungstate CuWOx type. Density functional calculations are in progress to help elucidating the physical and chemical nature of this unusual surface oxide phase.

Thu, 17:00 Organic PCBM field effect transistors: Analysis of the contact properties by combined photoemission spectroscopy and electrical measurements Mandy Grobosch1, Ingo Hörselmann2, Susanne Scheinert2, Martin Knupfer3, Gernot Paasch3

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2Technische Universit¨at Ilmenau, Ehrenbergstrasse 29, 98693 Ilmenau, Germany 3IFW Dresden, Helmholtzstraße 20, 01069 Dresden, Germany

Source/drain contacts in OFETs based on a solution prepared modified PCBM were characterized by combined X-ray and ultra violet photoemission spectroscopy (XPS, UPS) and electrical measurements of the OFET. Thereby the sample preparation for the different measuring principles has been realized in parallel, differing only in the layer thickness of the polymer. By means of UPS a reduced work function could be demonstrated for differently prepared, sputtered, and as-received Au and Al contacts in agreement with previous publications [1]. On top of the Al contacts a natural AlOx layer could be identified. For both the PCBM/Au and PCBM/Al systems UPS a hole injection barrier of 1.8 eV has been determined by UPS in agreement to previous published data. Considering the energy gap of 2.0 eV [2] for PCBM the electron injection barrier would be the same of 0.2 eV. In addition, the metal/organic interface Au/PCBM/Al has been investigated by means of combined XPS and UPS. The deposition of Au on the PCBM films results in a growth of gold clusters and a non-closed Au film. In contrast to the identical hole injection barriers for Au and Al bottom contacts as following from UPS, the OFET currents differ by more than two orders of magnitude. A possible origin of this striking discrepancy will be presented. [1] M. Grobosch et al., Adv. Mater. 19 (2007) 754. [2] Z.-L. Guan et al., Organic Electronics 11 (2010) 1779.

124 Thu, 17:20 Surface Induced Crystal Structures: Crystal Growth and Structure Solution Roland Resel1, Armin Moser1, Ingo Salzmann2, Raphaele Della Valle3, Michele Sferrazza4, Yves Geerts4 1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Humboldt-Universitätzu Berlin, Newtonstrasse 15, 12489 Berlin, Germany 3Universitádi Bologna, Via Zamboni, 33 - 40126 Bologna, Italy 4UniversitéLibre de Bruxelles, Campus de la Plaine, 1050 Bruxelles, Belgium

A large number of organic semiconductors exhibits polymorphism and well-known phenomena are specific crystallographic phases which are present exclusively in thin films. Such crystallographic phases are often denoted as surface induced phases, since the presence of a surface during the crystallisation is of primary importance for their formation. In general, such thin-film poly- morphs do not exist as macroscopic free standing single crystals. A number of surface induced crystal structures of conjugated molecules have been solved during the last years, examples are in particular application relevant molecules like pentacene. Within the talk the crystallisation behaviour of different calamitic conjugated molecules will be described: pentacene, sexithiophene and dihexyl-terthiophene. It is found that surface induced phases are formed by various techniques of thin film preparation. Solution based methods as well as physical vapour deposition can yield surface induced phases. Important parameters for preparation are the type of surface, the evaporation rate (or deposition rate) of the solvent during the thin film preparation and the temperature of the substrate during the crystallisation process. Similarities and differences in the molecular packing between known crystal structures and surface induced phases will be discussed. Of particular importance for the formation of surface induced crystal structures is the formation of the first molecular monolayer on a surface. Based on the experimental observations, thermodynamic issues will be finally discussed, especially if surface induced crystal structures are metastable phases or thermodynamically stable phases due to the presence of a surface.

Thu, 17:40 The electronic structure of pentacene monolayers on Ag(110) and Cu(110) Daniel L¨uftner1, Thomas Ules1, Michael Ramsey1, Georg Koller1, Peter Puschnig1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

We present a combined theoretical and experimental study of ordered monolayers of pentacene (5A) on Ag(110) and Cu(110). Theoretically, we have performed ab-initio calculations within the framework of density functional theory for the adsorbed monolayers and analyzed their electronic structure in terms of projected density of states and photoemission cross sections within the plane- wave final-state approximation. In addition, we have undertaken GW-calculations for isolated pentacene, bulk pentacene and a freestanding layer of pentacene to emphasizing that G0W0 corrections greatly improve DFT band gaps. Thereby, we also demonstrate that the G0W0 gaps are strongly dependent on the local environment of the pentacene molecule, an effect which is absent in DFT. Experimentally, the valence electronic structure of pentacene monolayers are studied by angle-resolved photoemission spectroscopy. Thereby, an extensive data set of the photocurrent I as a function of parallel momenta (kx,ky) and binding energy Eb has been obtained. This data cube is compared with simulated momentum maps of various pentacene molecular orbitals of an isolated molecule. Thereby, we can unambiguously identify four molecular states between the Fermi level and the top of the Ag d-band. By including the substrate in momentum map calculations, we are able to detect possible modifications of molecular states due to the interaction with the substrate. On comparing monolayer on Ag(110) and Cu(110), we find that 5A is oriented parallel to the substrate [1-10]-direction on Cu(110) and perpendicular to it on Ag(110).

125 Fri, 09:00 - 11:00, HS 15.02

Fri, 09:00

ZrO2 ultra-thin ﬁlms on Pd3Zr(0001): Structure and growth of metal clusters Joongil Jake Choi1, Ulrike Diebold1, Michael Schmid1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria

Despite its importance in many areas of industry such as catalysis, fuel cell technology and microelectronics, the surface structure and physical properties of ZrO2 are yet not well understood. We report a STM, AES and XPS study of ultra-thin ZrO2 films prepared by oxidation of a Pd3Zr(0001) crystal. A clean Pd3Zr(0001) surface with wide terraces (100 – 200 nm) was obtained ◦ by the Ar sputtering and annealing at 900 C. A homogeneous ZrO2 film was grown by 30 minutes ◦ −9 of oxidation of Pd3Zr(0001) at 450 C in an oxygen pressure of 5 × 10 Torr and annealing at ◦ 900 C for 10 minutes in UHV. The film has a fluorite√ √ trilayer (O-Zr-O) structure with an in-plane lattice constant of 0.350 ± 0.001 nm and a ( 43 × 43)R7.6◦ superstructure cell with respect to the substrate (asubst.= 0.5612 nm). Electron bombardment results in oxygen vacancies with a desorption cross-section of ∼ 170 pm2. When depositing small amounts of Au, we find single Au ad-atoms and clusters of various sizes (1 – 1.5 nm). The single Au atoms disappear at 470 K and larger clusters diffuse through the oxide to substrate at > 600 K. Pd clusters behave similar to Au, but diffuse through the oxide at a lower temperature ( > 500 K).

Fri, 09:20 AFM based electrical investigations on Ge nanodomes on Si(001) Markus Kratzer1, Christian Prehal1, Maria Rubezhanska2, Yury Kozyrev2, Sergey Kondratenko3, Christian Teichert1 1Montanuniversit¨atLeoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria 2 O. O. Chuiko Institute of Surface Chemistry , 17 Generala Naumova St., 03164, Kyiv, Ukraine 3Taras Shevchenko National University of Kyiv, Physics Dept. pr. Acad. Glushkova 2, Kyiv, Ukraine

The potential application of nanodots, nanowires, and nanodomes (NDs) in optoelectronics and photovoltaics has triggered intensive research on such low-dimensional nanostructures. In this work, we report on the electrical characterization of individual Ge nanodomes utilizing conductive atomic force microscopy (C-AFM), and photoconductive AFM (PC-AFM. The Ge ND samples were prepared by means of molecular beam epitaxy (MBE) on Si(001) substrates under ultra-high vacuum (UHV) conditions. Facetted islands exhibiting {113} and {15 3 23} facets could be identiﬁed via AFM topography measurements. The AFM based electrical characterizations were performed under ambient conditions in dark and under illumination. Two-dimensional current maps revealed a higher conductivity of the NDs compared to the surrounding. Conductivity variations within single NDs could be observed, which will be discussed with respect to Ge ND facets an silicon intermixing. Local current-to-voltage (IV) measurements on top of individual NDs revealed a dependence of the IV characteristics on the ND size. Additionally, the generation of a photovoltage due to light exposure has been observed. Support in the framework of the Ukrainian-Austrian projects M/139-2007 and UA-11/2009 is acknowledged.

126 Fri, 09:40, Keynote In situ observation of the growth of germanium nanoﬁbres Tom´aˇs Sikolaˇ 1, Miroslav Kol´ıbal2

1Brno University of Technology, Technick´a10, 61669 Brno, Czech Republic 2Brno University of Technology, Technick´a2, 61669 Brno, Czech Republic

Although several routes for fabrication of NWs exist, the vapor-liquid-solid (VLS) process is the most versatile approach in the production of group IV and III-V semiconductor NWs. In this method the metallic droplet has to be fed with the growth material, which is supplied in the form of gas molecules (CVD) or an atomic beam (PVD). The CVD method is used more frequently in fabrication of NWs than the PVD one, however, the latter method is more useful for in situ monitoring of the growth as its operation pressure is lower and, hence, more characterization techniques can be applied. In the contribution, in situ monitoring of h110i oriented Ge nanowire growth by SEM will be discussed. It will be shown that germanium nanowires can be grown by a vapor-liquid-solid process in h110i directions both on Ge(100) and Ge(111) substrates if very low supersaturation in the collector droplet is ensured. This is also supported by in-situ observations of nanowire kinking towards h111i direction occurring more frequently at higher evaporation rates. Further, it will be demonstrated that the hexagonal cross-section of germanium nanowires grown in the h110i direction by physical vapor deposition is a consequence of minimization of surface energy of the collector droplet. If the droplet is lost or solidiﬁed, two {001} sidewall facets are quickly overgrown and the nanowire exhibits a rhomboidal cross-section. This process can be controlled by switching between the liquid and solid state of the droplet, enabling the growth of nanowires with segments having diﬀerent cross-sections. These experiments will be supported by a theoretical model. In the end basic principles of the fabrication of regular arrays of nanowires by the guided growth of metallic droplets on substrates pre-patterned by focused ion beam will be discussed.

Fri, 10:20

Ordered Array of Single Au Adatoms on Fe3O4(001) with Remarkable Thermal Stability Zbynek Novotny1, Giacomo Argentero1, Zhiming Wang1, Michael Schmid1, Ulrike Diebold1, Gareth Parkinson1 1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria

We present a scanning tunneling microscopy investigation of gold deposited at the magnetite Fe3O4(001) surface at room temperature. This surface forms a reconstruction with c(2×2) symmetry [1], where pairs of Fe and neighboring O ions are slightly displaced laterally, forming un- dulating rows with ‘narrow’ and ‘wide’ adsorption sites. At fractional monolayer coverages, single Au adatoms adsorb exclusively at the ‘narrow’ sites, with no significant sintering up to annealing temperatures of 400◦ C[2]. The strong preference for ‘narrow’ site is possibly related to charge and orbital ordering within the first subsurface octahedral layers of the reconstructed Fe3O4(001) surface[3]. Because of their high thermal stability, the ordered Au atoms at Fe3O4(001) reconstructed surface should provide useful insights into the chemical reactivity of single atomic species. This material is based upon work supported as part of the Center for Atomic-Level Catalyst Design, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number #DE-SC0001058. [1] Pentcheva, R. et al. Phys. Rev. Lett 2005, 94, 126101. [2] Novotny, Z. et al., Phys. Rev. Lett. 108, 216103 (2012) [3] Lodziana, Z. Phys. Rev. Lett. 2007, 99, 206402.

127 Fri, 10:40 Strain and structure driven complex magnetic ordering of a CoO overlayer on Ir(100) Josef Redinger1, Florian Mittendorfer1, Michael Weinert2, Raimund Podloucky3

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria 2University of Wisconsin–Milwaukee, P.O. Box 413, 2200 E. Kenwood Blvd., Milwaukee, WI 53201-0413, USA 3University of Vienna, Sensengasse 8/7, 1090 Vienna, Austria

The magnetic ordering in the ultrathin c(10×2) CoO(111) film supported on Ir(100) has been investigated on the basis of ab-initio calculations. A close relationship between the local structural properties of the oxide film and the induced magnetic order was found, which leads to alternating ferromagnetically and anti-ferromagnetically ordered CoO segments. While the local magnetic order is directly related to the geometric position of the Co atoms, the mismatch between the CoO film and the Ir substrate leads to a complex long-range order of the oxide.

Fri, 11:00 - 11:30: Coﬀee break

128 Fri, 11:30 - 13:40, HS 15.02

Fri, 11:30, Keynote Microscopy and Spectroscopy of ultrathin organic layers and nanocrystals Peter Zeppenfeld1, Lidong Sun1, Thorsten Wagner1, Johannes Gall1, Daniel Queteschiner1, Michael Hohage1

1Johannes-Kepler-Universit¨at,Altenbergerstrasse 69, 4040 Linz, Austria

We report on the investigation of organic layers, thin films and nanocrystals using optical spectroscopy (RDS and SDR), Photo Emission Electron Microscopy (PEEM) and Fluorescence / Laser Scanning Confocal Microscopy (FM/LSCM). The combination of these methods enables us to monitor the growth in situ (RDS/SDR, PEEM) and to explore the correlation between the structure and morphology of the organic films with the electronic and optical properties at a microscopic scale (PEEM, FM/LSCM). Exploiting the polarization dependence of the light in RDS, PEEM and FM allows to determine the orientation of the molecules and to identify structural phase transitions. STM and LEED provide supplementary information on the arrangement of the molecules on the surfaces, whereas operating the PEEM with a He UV-lamp allows recording local UPS spectra from the grown films and from individual nanocrystals. Examples will be shown for sexithiophene (6T) and porphyrins on different single crystalline metal surfaces or mica.

Fri, 12:10 Cs doping of organic semiconducting monolayers: probing the electronic and geometric structure with angle resolved UPS Eva Reinisch1, Thomas Ules1, Georg Koller1, Peter Puschnig1, Markus Ostler2, Stephen Berkebile1, Thomas Seyller2, Michael Ramsey1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2University Erlangen N¨urnberg, Erwin-Rommel-Strasse 1, 91058 Erlangen, Germany

Cesium-deposition on ordered organic semiconducting thin films induces changes in the electronic structure and geometric orientation of the molecules. The current investigation is focused on rodlike Sexiphenyl (6P) and Pentacene (5A) molecules adsorbed on Ag(110) and Cu(110) substrates. In an undoped 6P monolayer on Cu(110), we observe flat lying molecules with the LUMO being filled by hybridisation with the surface. Upon Cs deposition first the molecules are tilted and decoupled from the surface, thus the LUMO is emptied. Further Cs deposition subsequently leads to electron charge transfer from the alkali metal to the molecular orbitals, filling first the LUMO, then LUMO+1, with increasing amounts of Cs. In contrast, in an undoped 6P monolayer on Ag(110) the LUMO is empty. Upon Cs deposition the 6P molecules on Ag(110) are doped similar to 6P on Cu(110). Significantly, prior to charge transfer doping, the initial Cs exposure azimuthally reorients the molecules of the 6P and 5A monolayer on Ag(110) from perpendicular to parallel to the substrate corrugation. This contrasts to Cu(110) where both molecules lie parallel to the Cu-rows before and after Cs deposition. This suggests a strong influence of the Cs atoms on the molecule-substrate bonding. The results will be discussed in the light of comparison between the experimental band (E, k) and momentum map (kx, ky) of ARUPS with DFT calculations. This work is supported by the Austrian Science Fund (FWF), projects P21330-N20 and P23190- N16.

129 Fri, 12:30 The inﬂuence of venting on the island size distribution observed for Hexaphenyl on mica Levent T¨umbek1, Christoph Gleichweit1, Karin Zojer1, Adolf Winkler1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

A frequently observed feature in the growth of para-hexaphenyl on freshly cleaved mica is the appearance of a bimodal island size distribution. In this case long needle-like islands, composed of lying molecules, are embedded in a sea of small clusters. Recently, it has been shown that the modification of the mica surface by Ar+ ion sputtering, or by the pre-adsorption of carbon or potassium, leads to a different growth behavior. Now the islands are of dendritic shape, composed of standing molecules. Surprisingly, again a bimodal growth mode can be observed. We have re-examined both growth scenarios in detail, using in-situ thermal desorption spectroscopy (TDS) and ex-situ atomic force microscopy (AFM). We found strong evidence that in both cases the small crystallites are caused by a dewetting process, which takes place when the in-vacuo grown films are exposed to air for the ex-situ AFM investigations. This was discovered when TD spectra were taken before and after venting the vacuum chamber. The very different origin of the two sets of islands is also constituted in a very different density, morphology and size distribution of the islands. The phenomenon of subsequent venting induced nucleation could be successfully described by Kinetic Monte Carlo (KMC) simulations. The result of these simulations was that about seven molecules constitute the critical island size.

Fri, 12:50 Growth and structure of Tetraphenylporphyrin on Cu(110)-p(2×1)O Margareta Wagner1, Sina Gusenleitner1, Tatjana Djuric2, Stephen Berkebile1, Roland Resel2, Michael Ramsey1, Falko Netzer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Tetraphenylporphyrin (H2TPP) has been grown on Cu-O and previously investigated elec- tronically and structurally by LEED, UPS, NEXAFS and XRD (ex-situ). Surprisingly the same surface structure has been found for both the monolayer and thick film, exhibiting the rather dilute H2TPP(5 10 3) plane. Whereas the narrow spacing and stacking of the layers in the bulk phase still lead to a dense thick film, the monolayer has been assumed to consist of a single H2TPP(5 10 3) layer only. However, this would be rather unusual, as porphyrines have been reported to form dense packed monolayers on various surfaces. In this LT-STM work the true structure of the H2TPP monolayer has been revealed. It could be demonstrated, that two H2TPP(5 10 3) planes merge into a commensurate single dense layer, which is stable due to the strong interaction with the Cu-O surface, and provides an excellent template for crystalline film growth. This work has been supported by the by the Austrian Science Foundation (FWF) within the National Research Network “Interface Controlled and Functionalized Organic Films” and the ERC Advanced Grant “SEPON”.

130 Fri, 13:10, Invited STM Studies of Surface-Supported Stable Hydrocarbon Radicals Stefan M¨ullegger1, Mohammad Rashidi1, Michael Fattinger1, Reinhold Koch1

1Johannes-Kepler-Universit¨at,Altenbergerstrasse 69, 4040 Linz, Austria

Stable free radicals can be stored and investigated under ambient conditions, which makes them desirable for applications as polarizing agents or novel magnetic materials as well as suitable model systems for investigating sp2 magnetism in reduced dimensions. We have studied the stable all-organic spin-1/2 radical, α,γ-bisdiphenylene-β-phenylallyl (BDPA), adsorbed on a weakly interacting metal support by low-temperature scanning tunneling microscopy (LT- STM). We report on the structure, self-assembly, frontier orbital electronic and magnetic properties, and radical-radical interactions at the atomic-scale.

131 132 12 Careers in Physics (PIE) HS 15.03

PIE, Phsics-Industry-Energy PIE, Physik-Industrie-Energie Doris A. Steinm¨uller-Neth, [email protected]

Thursday, 20th September 2012, HS 15.03 13:00 - 14:30 Time Presenter Title Industrial Research and gender aspects 13:00 - 13:15 Doris Steinmüller-Nethl – future for physicists in Europe? Herausforderungen in der Chipent- 13:15 - 13:30 Jochen Kraft wicklung fürdie industrielle Fertigung Beschäftigungsmöglichkeiten für 13:30 - 13:45 Martin Zimmerling Physiker in der Medizintechnik- Industrie Careers for Physicists’ in the Analyti- 13:45 - 14:00 Gerhard Murer cal Instruments Industry 14:00 - 14:15 Josef Siess Wie man Berufung zum Beruf macht

133 Thu, 13:00 - 14:30, HS 15.03

Thu, 13:00 Industrial Research and gender aspects – future for physicists in Europe? Doris Steinm¨uller-Nethl1 1KOMET RHOBEST GmbH, Exlgasse 20a, 6020 Innsbruck, Austria

Industry has a leading role in research, innovation and development. European companies need experts and scientists to boost their innovation and competitiveness. Physicists can fulfill these requirements. Industrial research opens the possibility to develop innovative technologies and products for the benefit of humankind. Interdisciplinarity and diversity are key factors for success. In this presentation the female physicist Doris Steinmüller-Nethl,will report about the challenges of her profession, hurdles she was confronted with and her passion for technology. This short glimpse into promising career options in industrial research should give an impetus for young physicists to trust and develop their talents and realize their opportunities.

Thu, 13:15 Herausforderungen in der Chipentwicklung fürdie industrielle Fertigung Jochen Kraft1 1AUSTRIAMICROSYSTEMS AG, Schloss Premstätten,8141 Unterpremstätten,Austria

Jochen Kraft absolvierte ein Diplom-Physik Studium an der Ruprecht-Karls Universitätin Heidelberg und promovierte an der Karl-Franzens UniversitätGraz im Gebiet Oberflächen- und Halbleiterphysik. Im Anschluss war er in der Chip Fertigung bei MICRONAS AG (Freiburg) als Defekt-Ingenieur beschäftigt. Seit 13 Jahren arbeitet er in der Forschungs- und Entwick- lungsabteilung von ams AG (früher: austriamicrosystems). ams ist ein führenderAnbieter von Analog-Lösungenim Bereich Power Management, Sensor und Sensor-Schnittstellen und Wireless. Das Schaltungsdesign, die Fertigung und der Chip Test ist bei ams unter einem Dach vereint. Dr. Kraft zeigt einige “High-Lights” aus seiner Entwickler-Tätigkeit bei ams. Insbesondere die neueren Aktivitätenim Bereich 3D Integration und Si-Durchkontakte werden vorgestellt. Die 3D Tech- nologie ermöglicht das Stapeln von Chips, z.B. die Herstellung eines Chips mit einem Sensor auf der einen Seite und der CMOS-Auswerteschaltung auf der anderen Seite. Der Signaltransfer durch den Chip findet mit Durchkontakten statt. Auf diese Weise werden Verdrahtungen vermieden, die zeitverzögerndwirken und relativ viel Platz benötigen.

134 Thu, 13:30 Beschäftigungsmöglichkeiten fürPhysiker in der Medizintechnik-Industrie Martin Zimmerling1

1Med-El Elektromedizinische Ger¨ateGmbH, F¨urstenweg 77a, 6020 Innsbruck, Austria

Forschung und Entwicklung werden in der Medizintechnik auch in Zukunft großgeschrieben werden, um neue Entwicklungen im Gesundheitssystem zu unterstützenund dieses und weiterhin finanzierbar zu halten. Daraus ergeben sich viele Betätigungsfelderauch fürPhysiker. Neben vielfältigenHerausforderungen im Forschungs- und Entwicklungsbereich finden sich auch im Pro- duktmanagement, in der Qualitätssicherung, im Zulassungsbereich sowie im Patentwesen spannende und interessante Aufgabenbereiche. Martin Zimmerling leitet als Physiker die Implanta- tentwicklung des weltweit tätigenösterreichischen Cochleaimplantat-Herstellers MED-EL. Er wird über seine Berufserfahrungen in der Medizintechnik berichten. Junge Physiker erfahren in dieser Präsentation auch, welche Fähigkeiten und Zusatzqualifikationen einen Einstieg und erfolgreiches berufliches Weiterkommen in der Medizintechnik erleichtern.

Thu, 13:45 Careers for Physicists in the Analytical Instruments Industry Gerhard Murer1 1Anton Paar GmbH, Ankerstrasse 6, 8054 Graz, Austria

The Analytical Instruments Industry is expected to have a sales volume of 45 Billion US$ in 2012 and employs some 300.000 people worldwide. The industry and the company the presenter works for are brieﬂy introduced. Of the 300.000 employed in the industry a considerable number is physicists. The presentation highlights career opportunities for physicists in the industry, in particular in the areas of research and technology development, product development, product management as well as sales.

Thu, 14:00 Wie man Berufung zum Beruf macht Josef Siess1 1EuropäischesService fürPersonalvermittlung und Unternehmensgründung,Paulanergasse 15/2, 1040 Wien, Austria

Ausgebildete Physiker und Physikerinnen nehmen verstärkt wichtige Managementaufgaben in großen Unternehmen, Konzernen und in der Politik wie auch als Forscher in ihren ureigensten Disziplinen wahr. Welche weiteren hard und soft skills von Unternehmungen und Organisationen gefragt und gefordert werden, wenn Spitzenpositionen besetzt werden, werden in diesem Vortrag angesprochen und an Beispielen gezeigt. Was junge Physiker und Physikerinnen fürihre eigene Karriereplanung beachten sollen, welche Zusatzqualifikationen oder Nischen (Spezial-) Kenntnisse außerhalb der wissenschaftlichen Uni-Laufbahn weiterhin nachgefragt sein werden, werden in diesem kurzen Vortrag beleuchtet und sollen Mut machen, auch abseits der Physiklaufbahn Bewerbungen gezielt zu platzieren. Wie man Berufung zum Beruf macht.

135 136 13 Posters

Wednesday, 19th September 2012 17:45 - 20:00 AMP Poster-ID Presenter Title Experimental Investigations of the Hy- perfine Structure of 143Nd+ Spectral POS-01 Naveed Anjum lines using Collinear Laser Ion Beam Spectroscopy An ion-photon interface mediated by a POS-02 Birgit Brandstätter cavity Omni-directional magnetic field mea- POS-03 Michaela Ellmeier surement by means of the Coupled Dark State Magnetometer (CDSM) Influence of sample temperature on the POS-04 Simon Eschlböck-Fuchs dynamics and emission line intensities of laser-induced plasma POS-05 Marcelo Goulart Electron driven chemistry close to 0 K Efficient wave function simulations in POS-06 Sebastian Krämer nonlinear quantum optics using an adaptive coherent state basis In situ ion-trap fabrication apparatus POS-07 Michael Niedermayr for low ion-heating rates Towards a nuclear clock with Thorium- POS-08 Matthias Schreitl 229

137 Wednesday, 19th September 2012 17:45 - 20:00 FAKT Poster-ID Presenter Title New Approaches for Improvement of POS-09 Stefan Brunner Time-of-Flight PET qBounce: Ein Frequenzstandard f¨ur POS-10 Gunther Cronenberg Gravitationsspektroskopie POS-11 Jacqueline Erhart Momentum Analysis in PERC Design of the Magnetic Shielding for POS-12 Philip Haiden PERC Strangeness Production in p-p Colli- POS-13 Katharina Isepp sions at FOPI POS-14 Michael Klopf Proton Spectroscopy with PERC Local-Duality QCD Sum Rules for POS-15 Wolfgang Lucha Pseudoscalar-Meson Form Factors Investigations of negative ion forma- POS-16 Martin Martschini tion in Middleton type ion sources Elektronen-Energie-Detektion f¨ur POS-17 Martin Moser PERC A new very-large Perfect Crystal Neu- POS-18 Thomas Potocar tron Interferometer Global Trigger Upgrade project for the POS-19 Babak Rahbaran CMS experiment at LHC Recent Advances in Accelerator Mass Spectrometry of the actinides at the POS-20 Stephan Winkler Vienna Environmental Research Ac- celerator

138 Wednesday, 19th September 2012 17:45 - 20:00 FKP & NESY Poster-ID Presenter Title The Impact of Temperature and Elec- POS-21 Johanna Akbarzadeh tric Fields on Surfactant-Molecules - an in-situ SAXS Study X-ray strain microscopy on Ge micro- POS-22 Tanja Etzelstorfer bridges Magnetic study of iron oxide nanopar- POS-23 Petra Granitzer ticles dispersed within porous silicon High Resolution X-Ray Diffraction POS-24 Nina Hrauda Studies on Arrays of SiGe Islands Proton implanted silicon wafers inves- POS-25 Stefan Kirnstötter tigated by electron beam induced current measurements Towards kinetic Monte-Carlo simula- POS-26 Martin Leitner tions with ab initio accuracy Wood templated inorganic nanoporous materials: Formation and water ad- POS-27 Roland Johann Morak sorption studied by in situ SAXS experiments Polarisation-dependent Raman char- POS-28 Maurizio Musso acterization of stibnite (Sb2S3) Numerical simulations of scanning gate POS-29 Josef Oswald experiments in the quantum Hall effect regime The nanomechanics of feather keratin POS-30 Silvia Pabisch studied by small-angle X-ray scattering

139 Wednesday, 19th September 2012 17:45 - 20:00 FKP & NESY (continued) Poster-ID Presenter Title Fabrication and optical characteriza- POS-31 Manuel Pacheco tion of CdSe quantum dots Defects in an iron-nickel meteorite ex- POS-32 Peter Parz amined with positrons Negative thermal expansion of carbon POS-33 Harald Rennhofer crystallites measured in single carbon fibres Toward polarisation entangled photon POS-34 Mathias Sassermann pairs from microcavity exciton polaritons Elektromagnetische Levitation – POS-35 Alexander Schmon Berührungsfreie Untersuchung von flüssigemMetall an der TU Graz Polarization-dependent Raman char- POS-36 Paolo Sereni acterization of Stibnite (Sb2S3) in the temperature-range 290K-77K Modeling disorder in self-assembled POS-37 Manuel Vieider monolayers with embedded dipoles

Wednesday, 19th September 2012 17:45 - 20:00 GEP Poster-ID Presenter Title Alfred Wegener: Second Expedition to POS-38 Martin Leitner Greenland - A photographic window to the past

140 Wednesday, 19th September 2012 17:45 - 20:00 LHS (PUS) Poster-ID Presenter Title POS-39 Hans Eck Kinder reisen durch die Wissenschaft Forschendes Lernen als Methode der POS-40 Erich Reichel Kompetenzf¨orderung POS-41 Engelbert Stuetz Mit Magnetfeldern h¨oren POS-42 Stefanie Anna Tritthart Papier erleben

Wednesday, 19th September 2012 17:45 - 20:00 MBU Ground based MAX-DOAS observa- POS-43† Carlos Armando Alberti tions of tropospheric trace gases in San Salvador, El Salvador Bioequivalent Solid-State Dosimetry: POS-44† Michael Hajek Current Trends and Future Develop- ments Review and Cross-comparison of Ma- troshka Phantom Measurements in POS-45† Christina Hofstätter Different Compartments of the Inter- national Space Station Korrelation relativer Feuchte und POS-46† Maryam Nikbakhti Stromumwandlungskoeffizient der Dünnschicht-Photovoltaik

† 5-minute poster-presentation on Thursday, 20th September 2012, 16:30 - 17:00

141 Wednesday, 19th September 2012 17:45 - 20:00 OGD Poster-ID Presenter Title AFM investigation of kraft pulp fiber POS-47 Christian Ganser swelling in controlled humidity Kinetic Monte Carlo Simulations of POS-48 Christoph Gleichweit Nucleation and Thin Film Growth of Hexaphenyl on Amorphous Mica Susceptibility measurements of Ni POS-49 Michael Hohage nanostructures on Cu(110) Dynamic plowing lithography and 6P POS-50 Markus Kratzer thin film growth on graphene investigated by atomic force microscopy Morphological investigations of viscose POS-51 Patrice Kreiml fibers by atomic force microscopy Growth and structure of WOx POS-52 David Kuhness nanolayers on bare Cu(110) and Cu(110)(2×1)O surfaces Adsorption of Xylan onto Bleached POS-53 Albrecht Miletzky Softwood Fibers The contact charging of insulators by POS-54 Monika Mirkowska atomic force microscopy Anisotropic growth of ultrathin Mn- POS-55 Thomas Obermueller oxide nanostructures on Ag(100) Surface Chemistry Chamber for anal- POS-56 Jiˇr´ıPavelec ysis of Oxides Microscopical electrical investigations POS-57 Andreas Pavitschitz of grain boundaries in ZnO varistor ceramics

142 Wednesday, 19th September 2012 17:45 - 20:00 OGD (continued) Poster-ID Presenter Title Structure Solution of Surface Induced POS-58 Alexander Pichler Crystal Structures: Selected Examples of Calamitic Conjugated Molecules Influence of potassium on the nucle- POS-59 Bernhard Putsche ation and growth of para-hexaphenyl on mica Thin cellulose films as model systems POS-60 Sebastian Rohm for paper-fibres Initial growth of Rubicene on Silicon POS-61 Boris Scherwitzl Oxide Bismuth surface phonon modes from POS-62 Anton Tamtögl helium atom scattering experiments Attachment limited versus diffusion limited nucleation of organic POS-63 Levent Tümbek molecules: Hexaphenyl on sputter- modified mica Displacement and Replacement in Or- POS-64 Thomas Ules ganic Heterostructures Reversible transitions between surface POS-65 Zhiming Wang reconstructions on SrTiO3 Investigation of the surface charge of POS-66 Frederik Weber Viscose Fibres by XPS and ATR Selective Photo-induced Cross-linking of Polynorbornens: Towards the Fab- POS-67 Archim Wolfberger rication of Polymer 2D- and 3D- Mi- crostructures

Wednesday, 19th September 2012 17:45 - 20:00 PMP Poster-ID Presenter Title POS-68 Maurizio Musso Raman investigation of tannin foams The eﬀect of sacriﬁcial bonds on the POS-69 Soran Nabavi mechanical behavior of a single polymer chain- A Monte Carlo study

143 Wed, 17:45 - 20:00

POS-01, AMP, Wed, 17:45 Experimental Investigations of the Hyperﬁne Structure of 143Nd+ Spectral lines using Collinear Laser Ion Beam Spectroscopy Naveed Anjum1,2, Nadeem Akhtar1,2, Harry H¨uhnermann1,3, Laurentius Windholz1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Optics Labs. P. O. Box 1021, Nilore Islamabad, Pakistan 3Department of Physics, University of Marburg, Germany

We have used the high resolution technique of collinear laser ion beam spectroscopy (CLIBS) for Doppler free investigations of the hyperfine structure (hfs) of spectral lines of singly ionized Neodymium-143 (143Nd+). Hyperfine structure is caused by the electromagnetic interaction between the nucleus and the electron shell. The study of the hyperfine structure of ions can provide useful information on the nuclear structure and electronic properties of the ions. We used natural Nd in metallic form to produce Nd ions using a surface ion source of Johnson type. Natural Nd is a mixture of five stable and two radioisotopes and the natural abundance of 143Nd is just 12.2%. The ions are accelerated to 20 kV and then mass separated by an 80◦ magnet. A collimated ion beam is obtained in the interaction region. In the interaction region the ion velocity is tuned by applying an additional voltage and keeping the laser frequency constant (Doppler tuning). A ring dye laser, pumped by an Argon ion laser, is used as the excitation source and we used dyes Rhodamine 6G and Sulforhodamine B (Kiton Red) to obtain the desired laser wavelengths. Laser induced fluorescence is recorded by using a photomultiplier tube and a photon counter. Magnetic dipole constants A and electric quadrupole constants B of the involved levels have been determined using a fit program. The accuracy of our results is better than that of published values.

POS-02, AMP, Wed, 17:45 An ion-photon interface mediated by a cavity Birgit Brandst¨atter1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria

Quantum networks, in which atoms at quantum nodes are linked by photonic channels, offer a compelling solution to the challenge of scalability in quantum computing. In these networks, optical cavities provide an interface between photons and atoms. We use a trapped calcium ion, which allows for efficient initialization, coherent manipulation, and readout of the quantum state. The ion is coherently coupled to the polarization state of single photon via a high-finesse cavity by driving a vacuum-stimulated Raman transition. We show state mapping of an arbitrary electronic superposition state of the ion to a polarization superposition state of a single photon. In a new experimental setup, we plan to increase the coherent coupling between ion and photon to reach the strong-coupling regime by decreasing the cavity mode volume using fiber Fabry-Perot cavities.

144 POS-03, AMP, Wed, 17:45 Omni-directional magnetic ﬁeld measurement by means of the Coupled Dark State Magnetometer (CDSM) Michaela Ellmeier1, Roland Lammegger1, Andreas Pollinger2, Werner Magnes2, Laurentius Windholz1 1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Osterreichische¨ Akademie der Wissenschaften, Schmiedlstrasse 6, 8042 Graz, Austria

The CDSM magnetometer is a new type of optical pumped magnetometer, which measures the scalar value of the magnetic field. The measurement principle is based on the coupling of two dark state resonances established by the coherent population trapping (CPT) effect. The dark state resonances are excited by a circularly polarized, polychromatic laser field consisting of two frequency components 6.8 GHz apart from each other. As a consequence, six magnetic field dependent dark states are created within the hyperfine structure of the 87Rb D1 line, which are combined by a multi-stage modulation process to three coupled dark state resonances. The magnitude of the magnetic field is obtained by extracting the appropriate modulation frequency lying in the range of 300 Hz-1 MHz by means of phase sensitive detection techniques. The benefit of this approach is a significant reduction of the (buffer gas induced) temperature shift of the dark resonances. In contrast to other scalar magnetometers, the CDSM can measure magnetic fields independent on their direction (without the so called dead zones). This novelty is achieved by a proper selection of the resonance with maximum amplitude during the permanent operation of the magnetometer. Therefore, exact knowledge about the relative strengths of the dark resonances is necessary. We demonstrate that the optical pumping effect causes an asymmetry between the coupled resonances, resulting in a totally different angular dependence of the dark resonance amplitudes compared to predictions of theoretical models. This behaviour is used with benefits in the CDSM operation dynamics.

POS-04, AMP, Wed, 17:45 Influence of sample temperature on the dynamics and emission line intensities of laser-induced plasma Simon Eschlböck-Fuchs1, Michael Haslinger1, Andreas Hinterreiter1, Philipp Kolmhofer1, Norbert Huber1, Roman Rössler2, Johannes Heitz1, Johannes Pedarnig1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria 2Voest Alpine Stahl, Voest-Alpine-Strasse 3, 4031 Linz, Austria

We investigate the influence of sample temperature on the dynamics of the laser induced plasma and on the emission intensities in laser-induced breakdown spectroscopy (LIBS). Bulk aluminum, boron doped silicon, and metallurgical slag samples are heated in air up to temperature TS ≤ 500 ◦C and are irradiated by Nd:YAG laser pulses (wavelength 1064 nm, pulse duration approx. 7ns). The plasma dynamics is investigated by fast time-resolved photography. LIBS spectra are taken with an Echelle spectrometer in combination with an intensified CCD camera. For all sample materials investigated the temporal evolution of the plume size and of the LIBS intensities varies systematically with TS. The height and width of the plasma plume and the luminosity of the plasma, as measured by fast photography, increase with increasing temperature. For Al and Si the plasma lifetime is extended to ∼ 10 µs at TS = 500 ◦C (compared to ∼ 4 µs at TS = 20 ◦C). For slag samples the plasma lifetime does not significantly vary with TS. Increasing emission line intensities are observed for all samples at high temperature. We apply the calibration-free LIBS method to analyze the measured emission spectra and to determine the concentration values for the major oxides in slag at different sample temperature. The LIBS analysis of multi-component samples at high temperature is of interest for technical applications. Acknowledgements: We thank the Austrian Federal Ministry of Economy, Family and Youth and the National Foundation for Re- search, Technology and Development for financial support.

145 POS-05, AMP, Wed, 17:45 Electron driven chemistry close to 0 K Marcelo Goulart1, Peter Bartl1, Samuel Zöttl1, Mathias Daxner1, David Gschliesser1, Johannes Postler1, Carolina Guedes Matias1, Benjamin Puschnigg1, Violaine Vizcaino1, Christian Leidlmair1, Harald Schöbel1, Lukas An der Lan1, Stephan Denifl1, Andreas Mauracher1, Michael Probst1, Olof Echt2, Andrew Ellis3, Paul Scheier1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria 2University of New Hampshire, DeMeritt Hall 323, 9 Library Way, Durham, New Hampshire, 03824, USA 3University of Leicester, University Rd, Leicester, LE1 7RH, UK

Homogeneous as well as heterogeneous clusters are formed upon pickup of individual atoms and molecules by He nanodroplets. Evaporative cooling of the He matrix leads to an isothermal temperature of 0.37 K. Fragmentation of the dopant cluster during the pickup process is completely quenched by the surrounding He matrix, leading to a neutral cluster size distribution free of any magic numbers. Positive and negative ion formation is studied via electron bombardment of the doped He nanodroplets utilizing mass spectrometry. Intensity anomalies of the cluster size distributions indicate fragmentation processes of the dopant clusters after the ionization process and reflect the stability of the differently sized charged clusters. Electron ionization of He nanodroplets doped with methanol (M) forms predominantly the protonated cations MnH+. Several other abundant + cluster ion series can be assigned as (H2O)xMnH with x = 1 – 5. The intracluster reaction leading to the formation of H2O requires a minimum number of methanol molecules, which is n = 5+4x. This work is financially supported by the FWF (P19073, P23657, and L633)

POS-06, AMP, Wed, 17:45 Eﬃcient wave function simulations in nonlinear quantum optics using an adaptive coherent state basis Sebastian Kr¨amer1, Helmut Ritsch1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria

We show that a suitable set of coherent basis states placed on a discrete hexagonal grid can be used to numerically very accurately represent general quantum states in a memory eﬃcient way. Adding an algorithm for dynamic basis adaptation allows highly accurate Quantum Monte Carlo wave function simulations with small basis sets. At the example of the intricate nonlinear dynamics of an optical parametric oscillator around threshold, we demonstrate that this approach yields accurate time dependent solutions with a substantially smaller basis sets than required for a photon number basis. Above threshold the adaptive basis splits into localized subsets allowing eﬃcient representation of bimodal or even more complex phase space distributions and directly yields an intuitive physical picture of the ongoing dynamics.

146 POS-07, AMP, Wed, 17:45 In situ ion-trap fabrication apparatus for low ion-heating rates Michael Niedermayr1

1University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria

One promising approach for scalable quantum-information-processing architectures is based on miniaturised surface ion traps. At present, one significant limit to miniaturisation is set by the heating rate of ions, which increases as the ions approach the trap surface. The mechanism of this heating is not yet fully understood, but experimental results indicate that one likely cause is contamination on the surface of the trap electrodes. This is present even after only the briefest exposure to atmosphere. This effect might be mitigated by performing the final trap-fabrication steps in situ, in vacuum. We describe a system to investigate the heating rates of contamination-free gold surface traps. The cryogenic ion-trap chamber is equipped with a thermal evaporation source in vacuum which allows in situ coating of the trap surface with a fresh gold layer. The heating rate will be measured before and after the evaporation.

POS-08, AMP, Wed, 17:45 Towards a nuclear clock with Thorium-229 Matthias Schreitl1, Thorsten Schumm1, Georgy Kazakov1, Georg Winkler1, Georg Steinhauser1

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

An improvement of the current time standard could be achieved by exploiting optical transitions with long lifetimes and narrow line widths. Nuclear transitions, which can be more stable against external perturbations, usually have energies in the range of keV or even MeV. Thorium-229 however is predicted to provide a unique excited state only 7.6±0.5 eV [1] above the ground state in the range of UV lasers. An expected lifetime of several hours [1] makes this transition an excellent candidate for a new time standard, with a potential to outperform existing clocks by orders of mag- nitudes. Our experimental approach consists in embedding Th4+ in the UV-transparent crystal structure of CaF2. This provides the advantages of working with a room-temperature solid-state sample with a great number of nuclei. The next steps include the characterization of the crystals doped with Th-232 in order to ensure the transparency in the relevant wavelength region, the reliable substitution of the Thorium ions in the crystal lattice and the role of defects. A broadband UV-lamp will subsequently be used to try to excite the predicted nuclear transition and detect ﬂuorescence in a crystal doped with Th-229. A frequency comb is currently set up which will be transferred to the 160 nm region by a high-harmonic generation build-up cavity and will be used as a precision measurement tool for comparison to other frequency standards. [1] Beck et al., Phys. Rev. Lett. 98, 142501 (2007)

147 POS-09, FAKT, Wed, 17:45 New Approaches for Improvement of Time-of-Flight PET Stefan Brunner1, Lukas Gruber1, Albert Hirtl2, Johann Marton1, Martin Jankovec2, Peter Knoll3, Ken Suzuki1 1Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria 2Medical University of Vienna, W¨ahringerG¨urtel18-20, Leitstelle 3L , 1090 Wien, Austria 3Wilhelminenspital, Montleartsrasse 37, 1160 Wien, Austria

Advances in detector technology led to the construction of commercial time of flight (TOF) positron emission tomography (PET) devices, resulting in enhanced image contrast, lower patient’s dose and shorter examination times. Commercial TOF-PET scanners with coincidence time resolutions of 500-600 ps FWHM are already available. Goal of this work is the improvement of time resolution for TOF-PET using Silicon photomultipliers (SiPM) and the Cherenkov effect. Along with many comparable features to ordinary vacuum photomultipliers, SiPMs are considerably smaller in size and insensitive to magnetic fields, which makes them usable for hybrid devices such as PET-NMR. The use of the Cherenkov effect at gamma energies of 511keV should help to improve time resolution of PET detectors dramatically. As Cherenkov photons are emitted almost instantaneously, compared to scintillation photons, the ability to detect and distinguish them from the scintillation signals, provide precise time stamps for TOF. First measurements using PMTs have been accomplished successfully. For the development of a future TOF-PET prototype, Monte Carlo (MC) simulations using the framework GATE and SLitrani are performed to optimise the experimental setup (pixel size, material, arrangement of the SiPMs). The simulated raw data have been analysed by self-developed software and first sinograms have been calculated. In this work the results of recent measurements on the time resolution of our setup, calculations and measurements related to the detection of Cherenkov photons at energies of 511keV, and latest results of MC simulations on new detector designs, will be presented.

POS-10, FAKT, Wed, 17:45 qBounce: Ein Frequenzstandard f¨ur Gravitationsspektroskopie Gunther Cronenberg1, Hanno Filter1, Tobias Jenke1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

Wir wenden eine Spektroskopiemethode quantisierter Zuständeultrakalter Neutronen im Gravi- tationspotential an. Diese Methode erlaubt präziseMessungen der quantenmechanischen Ubergangsfrequenzen¨ eines Schrödinger-Wellenpakets, welches im Schwerefeld der Erde auf einem Neutronenspiegel os- zilliert. Den Ubergangsfrequenzen¨ entsprechen dabei Energiedifferenzen der Eigenzuständeim Pi- coelektronenvoltbereich, welche nur von der Neutronenmasse, der lokalen Erdbeschleunigung, sowie vom Planckschen Wirkungsquant abhängen.Messungen mit ultrakalten Neutronen erlauben aufgrund ihrer nicht vorhandenen Ladung sowie extrem geringer Polarisierbarkeit eine Sensitivität auf das Newtonsche Gravitationsgesetz oder Abweichungen durch hypothetische, kurzreichweit- ige Wechselwirkungen ohne den Einfluss elektromagnetischer Störeffekte.Damit könnenGrenzen auf theoretisch interessante Modelle wie Große Extradimensionen der Raumzeit oder Axionen in dem vergleichsweise wenig untersuchten Mikrometerbereich abgeleitet werden. Eine weitere Aus- baustufe dieser Methode bringt als Vorteil die Selbstfokussierung des Aufbaus, welche eine größere Geschwindigkeitsklasse und damit eine höhereZählrateder untersuchten Neutronen erlaubt.

148 POS-11, FAKT, Wed, 17:45 Momentum Analysis in PERC Jacqueline Erhart1, Gertrud Konrad1, Xiangzun Wang1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

The new user facility “Proton and Electron Radiation Channel” (PERC) supplies an intense beam of charged decay products arising from the beta decay of free neutrons. This weak interaction process tests the Standard Model and searches for possible extensions. Different detector systems are under development in order to study angular correlations involving the neutron spin, the energies and the momenta of the β-decay products (electrons and protons). Already existing beta decay spectrometers were focused on the measurement of electron and proton energy while PERC permits precise momentum spectroscopy of charged particles for the first time. At the exit of PERC, the electrons and protons leaves the magnet system with a field strength of 0.5T. Therefore, the magnetic field has to drop down rapidly and guarantee the non-adiabatic motion of the particles at the passage to the momentum spectrometer. The new detection concept has to provide a weak ver- tical magnetic field to separate the particles due to their momenta and charges. The electrons and protons are detected by position sensitive detectors. In this way, electrons and protons can be measured at the same time. The new concept of analyzing the momentum spectra provides an increased resolution in the low energy scale which is needed for investigating, e.g., the Fierz interference term.

POS-12, FAKT, Wed, 17:45 Design of the Magnetic Shielding for PERC Philip Haiden1, Jacqueline Erhart1, Harald Fillunger1, Miklos Horvath1, Gertrud Konrad1, Stefan Schwarz1, Xiangzun Wang1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

The new facility PERC (Proton Electron Radiation Channel) is a novel source of neutron decay products. PERC is currently under development by an international collaboration and will be installed at the FRM II in Garching, Germany. The main component of PERC is a more than 11 m long superconducting magnet system, with a strong longitudinal magnetic field of 0.5 T up to 6 T. In order not to disturb other experiments in the vicinity of PERC, we have designed a magnetic field return yoke for the magnet system. The following aspects must be taken into consideration: • the magnetic stray field must be suppressed to the cardiac pacemaker level, • the internal magnetic field and its homogeneity should not be disturbed, • the additional forces onto the coils must not be destructive, and • the magnetic shielding must deal with the limited space conditions. We will show that for experimental reasons, the magnet geometry is non-axisymmetric and therefore has to be simulated in three dimensions. In order to reduce the computing time and, at the same time, increase the numerical accuracy, we simulated only one half of the geometry by taking advantage of the symmetry of the magnet and its shielding. The design of the magnetic shielding for PERC will be presented in this poster: The finite element method (COMSOL Multiphysics) has been used to determine the most suited geometry for the magnetic shielding. Various geometries and combinations of shielding materials of non-linear permeability have been simulated.

149 POS-13, FAKT, Wed, 17:45 Strangeness Production in p − p Collisions at FOPI Katharina Isepp1

1Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria

According to theoretical predictions [1] deeply bound kaonic states are possibly created in proton-proton collisions. To verify them experimentally the FOPI detector at GSI [2] investigated a 3.1 GeV proton beam targeting on liquid hydrogen in 2009. In this reaction the Λ(1405) resonance plays a special role. It can be interpreted as a pK− bound state which serves as a doorway state to produce the deeply bound state ppK−. This state decays eventually with a large branching ratio into a Λ hyperon and a proton. The poster presents the reconstruction of the Λ involved in the p + p → pK+Λ ﬁnal state from its decay products π− and p. [1] Y. Akaishi and T. Yamasaki, PRC 76, 045201, 2007 [2] www.gsi.de / www-fopi.gsi.de

POS-14, FAKT, Wed, 17:45 Proton Spectroscopy with PERC Michael Klopf1, Jacqueline Erhart1, Gertrud Konrad1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

The PERC collaboration will perform high-precision measurements of angular correlations in neutron beta decay at the FRM II in Garching, Germany. The new facility PERC, a novel source of neutron decay products, is designed to improve the sensitivity of neutron decay studies by one order of magnitude. Depending on the angular correlations studied with PERC, the analysis of the extracted decay electrons and protons is performed with different and specialized detectors. As far as protons are concerned, PERC will feed a charged particle spectrometer, for instance an adapted spectrometer which can partially be based on the aSPECT detection system. The analysis of the decay protons is based on a precise energy measurement, by means of an electrostatic filter or by time-of-flight measurement. Then, e.g., the electric potential between the decay and filter regions (0 – 780 V) has to be known with an accuracy of better than 10 mV. Up to the completion of the PERC instrument, systematic uncertainties in the analysis of decay protons are investigated with the aSPECT spectrometer. In order to, e.g., avoid electrical breakdowns initiated by and discharges due to field emission from the high voltage electrodes, the high voltage system has been redesigned. Besides the physics motivation, the optimization of the aSPECT spectrometer, the detection concept and the dominant systematic uncertainties for PERC will be presented in this poster.

150 POS-15, FAKT, Wed, 17:45 Local-Duality QCD Sum Rules for Pseudoscalar-Meson Form Factors Wolfgang Lucha1, Irina Balakireva2, Dimitri Melikhov1

1Osterreichische¨ Akademie der Wissenschaften, Nikolsdorfer Gasse 18, 1050 Wien, Austria 2Moscow State University, SINP, 119991, Moscow, Russia

Utilizing the local-duality formulation of QCD sum rules, we scrutinize anew some strange ﬁndings for the charged-pion elastic form factor and for the form factor describing the neutral-pion transition to one real and one virtual photon within a broad range of momentum transfers. The uncertainties of the local-duality approximation to the QCD sum-rule formalism are estimated by analyzing, in parallel to QCD, quantum-mechanical potential models, where the exact form factors may be easily obtained by solving the Schr¨odingerequation and then compared with the local- duality sum-rule outcomes. From these studies, we expect the accuracy of the predictions of simple local-duality models to improve very fast with increasing momentum transfer and thus regard large deviations from the elastic pion form factor’s local-duality behaviour, recently predicted by some hadron-structure models, as rather unlikely. Furthermore, in startling contrast to the excellent 0 ∗ agreement of the local-duality results for the (η, η , ηc) → γ + γ transition form factors, recent BABAR measurements of the π → γ + γ∗ transition form factor imply inexplicable local-duality violations which even rise with momentum transfer.

POS-16, FAKT, Wed, 17:45 Investigations of negative ion formation in Middleton type ion sources Martin Martschini1, Pontus Andersson1, Oliver Forstner1, Robin Golser1, Dag Hanstorp2, Anton Lindahl2, Johan Rohl´en2

1University of Vienna, Währinger Strasse 17, 1090 Wien, Austria 2University Gothenburg, Fysikgränd3, Plan 8 rum F8032, SE-412 96 Göteborg, Sweden

Since 1977, sputter ion sources of the Middleton type have been the main tool used to create stable, intense negative ion beams for Accelerator Mass Spectrometry (AMS). Nevertheless, the theory behind negative ion formation is not fully agreed upon and recipes for high current output differ from lab to lab. A better understanding of the sputtering process is expected to allow further optimization of negative ion sources and thereby enhance the abundance sensitivity of AMS for several radioisotopes. As part of the work in trying to unravel the mechanisms of hard sputtering in a cesium rich environment, we have resolved the spectrum of blue light emitted from the cathode region during high current output. A fiber coupled spectrometer was used to detect light in the wavelength region 200 to 1100 nm. When sputtering a carbon target, the emitted light consists almost entirely of persistent lines from neutral cesium. To our surprise, the spectra from aluminum or copper targets showed also persistent lines from Cs+. In another experiment, the effect of contin- uous wave laser light directed onto the cathode surface was studied. Independent from wavelength, the laser light induced a significant change in oxygen, sulfur and chlorine negative ion production from a AgCl target. Approximately 100 mW of laser light changed the elemental composition of the ion beam by one order of magnitude. This technique was successfully applied during a regular AMS measurement of 36Cl at VERA (Vienna Environmental Research Accelerator). The physics behind the effect still requires further investigations.

151 POS-17, FAKT, Wed, 17:45 Elektronen-Energie-Detektion f¨urPERC Martin Moser1, Thomas Cervinka1, Jacqueline Erhart1, Gertrud Konrad1, Sebastian Maaß1, Xiangzun Wang1, Hartmut Abele1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria

Das freie Neutron zerfälltauf Grund der schwachen Wechselwirkung über den Betazerfall in ein Proton, ein Elektron und ein Elektron-Antineutrino. Uber¨ die Winkelkorrelationen dieser Teilchen ist es möglich, die Gültigkeit des Standardmodells der Teilchenphysik zu überprüfenbzw. zu erweit- ern. Das neue Instrument PERC ermöglicht es, die Korrelationskoeffizienten zwischen dem Neutro- nenspin und den Impulsen der Zerfallsprodukte in noch nie dagewesener Präzisionzu messen; da die Zerfallsrate bei 106 liegen wird. Das zum Einsatz kommende Elektronenspektrometer basiert auf dem von unserer Arbeitsgruppe an der UniversitätHeidelberg entwickelten und vom Atominstitut der Technischen UniversitätWien, zur Erhöhung der Effizienz, adaptierte Spektrometer PERKEO3. In Wien wird einer der Detektoren von PERKEO3 charakterisiert und dessen fürdie Elektronen- spektroskopie relevanten Systematiken untersucht. Das Ziel ist Elektronenspektroskopie auf 10−4 Niveau. Die Energiedetektion erfolgt dabei über Szintillatoren mit Photomultiplierauslese, auf de- nen besonderes Augenmerk liegt: Auf Grund ihrer kurzen Auslesezeit und hohen Zeitauflösung ist es möglich, bei besonders hohen Zählratenzu arbeiten, was gerade fürPERC von großer Be- deutung ist. Zusätzlich wird auch die Stabilitätdes Messsystems erhöht und charakterisiert, um eine mögliche Variation von Zerfallskonstanten zu bestimmen. Ergänzendzu den direkten Sta- bilitätstestsmit Eichproben werden auch Monte Carlo Berechnungen durchgeführt,die sowohl das Rückstreuverhalten sowie die Elektronenabsorption und -transmission aus dem Szintillationsmate- rial als auch dem Detektorgehäuseaus Edelstahl untersuchen. Diese Simulationen werden mittels der speziell dafürentwickelten Simulationssoftware CASINO durchgeführt.

POS-18, FAKT, Wed, 17:45 A new very-large Perfect Crystal Neutron Interferometer Thomas Potocar1, Ulrich Kuetgens2, Michael Zawisky1, Harald Huber1

1Vienna University of Technology, Stadionallee 2, 1020 Wien, Austria 2Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

The diﬀerent stages of the machining of the largest crystal interferometer are presented. Path length, beam separation and enclosed beam area are exceeding, by far, the dimensions of hitherto prepared interferometer crystals. Due to its large dimensions and the steplike cut middle plates it can be used as multi-purpose instrument: The interferometers lower part serves as a compact, extremely sensitive angle measuring device. The upper part is mainly used for gravitation experiments where three interference loops can be used with the same interferometer. This research was funded by the Austrian Science Fund (FWF): Project I530-N20.

152 POS-19, FAKT, Wed, 17:45 Global Trigger Upgrade project for the CMS experiment at LHC Babak Rahbaran1 1Osterreichische¨ Akademie der Wissenschaften, Nikolsdorfer Gasse 18, 1050 Wien, Austria

The electronics of the ﬁrst Level Global Trigger (GT) of CMS is the last stage of the Level-1 trigger system. At LHC up to 40 million collisions of proton bunches occur every second, resulting in about 800 million proton collisions. The CMS Level-1 Global Trigger, a custom designed electronics system based on FPGA technology and the VMEbus system, performs a quick on-line analysis of each collision every 25 ns and decides whether to reject or to accept it for further analysis. Various parts of the CMS trigger and in particular the Level-1 hardware trigger will be upgraded to cope with increasing luminosity, using more selective trigger conditions at Level-1 and improving the reliability of the system. The CMS trigger group of the Institute of High Energy Physics in Vienna (HEPHY) is involved in the Level-1 trigger of the CMS experiment at CERN. As part of the Trigger Upgrade, the Level-1 Global Trigger will be redesigned and implemented in MicroTCA based technology, which allows engineers to detect all possible faults on plug-in boards, in the power supply and in the cooling system. The upgraded Global Trigger will be designed to have the same basic categories of functions as the present GT, but will have more algorithms and more possibilities for combining trigger candidates. Additionally, reconﬁgurability and testability will be supported based on the next system generation.

POS-20, FAKT, Wed, 17:45 Recent Advances in Accelerator Mass Spectrometry of the actinides at the Vienna Environmental Research Accelerator Stephan Winkler1, Peter Steier1, Alfred Priller1, Josef Buchriegler1, Robin Golser1

1University of Vienna, W¨ahringer Strasse 17, 1090 Wien, Austria

Actinides have wide application in environmental science, both as tracer and as dating tool. Accelerator Mass Spectrometry (AMS) has been shown to allow for the lowest isotope ratio detection limits for actinides. However, careful design of the spectrometer and an understanding of beam and atomic physics is required to achieve the detection limits required for the measurement of naturally occurring 236-U or the artiﬁcially produced plutonium isotopes beyond mass 240 in the general environment. We present our latest developments and improvements at the Vienna Environmental Research accelerators heavy isotope beam-line and give also a wider perspective on the design of an ideal heavy-ion AMS system.

153 POS-21, FKP & NESY, Wed, 17:45 The Impact of Temperature and Electric Fields on Surfactant-Molecules - an in-situ SAXS Study Johanna Akbarzadeh1, Sylvia Flaig2, Nicola Huesing2, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria 2Paris-Lodron University Salzburg, Hellbrunner Strasse 34, 5020 Salzburg, Austria

The combination of different synthetic strategies such as sol-gel processing together with templating approaches have been proven to be an effective method in the preparation of long range ordered mesoporous materials. However, for many applications (e.g. microelectronic devices, membranes...) not only highly ordered mesopores but also a precisely defined pore orientation would be desirable. One way to achieve such highly oriented mesopores is the exposure of the sample to an electric field during the sol-gel process. Electric field induced orientation of mesopores has already been reported in literature, for example Ku et al. have shown that the application of an low-strength electric field in the preparation of surfactant - templated nanoscopic silica fibers leads to oriented nanochannels with both micrometer and nanometer levels of hierarchy. Trau et al. have demonstrated that the use of high-strength electric fields in the production of nanoscopic patterned thin films leads to nanochannels oriented parallel to the applied electric field. In this work we investigate the temperature dependence of different (anionic, cationic and zwitterionic) surfactant molecules in an external electric field ranging from some kV/m up to 1 MV/m. These molecules will further serve as a template phase in the sol-gel process to produce long range ordered and highly oriented mesoporous materials. The structural change on the nanometer level is followed in-situ by small-angle X-ray scattering.

POS-22, FKP & NESY, Wed, 17:45 X-ray strain microscopy on Ge micro-bridges Tanja Etzelstorfer1, Martin S¨uess2, Gustav Schieﬂer3, Ana Diaz3, Hans-Christian Sigg3, Vincent Jaques4, Daniel Chrastina5, Giovanni Isella5, Ralph Spolenak2, Julian Stangl1

1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria 2ETH Z¨urich,Wolfgang-Pauli-Strasse 16, 8093 Zurich, Switzerland 3Paul Scherrer Institut Paul Scherrer Institut, 5232 Villigen PSI, Switzerland 4ESRF, 6 Rue Jules Horowitz, BP 220, 38043 Grenoble Cedex 9, France 5Politecnico di Milano, Piazza L. da Vinci, 32, 20133 Milano, Italy

In the SiGe system optical emitters are difficult to realize due to the indirect band gap. Em- ployment of tensile strain in Ge is a promising route to shift to the indirect transition. Technical realization of required strain values of a few per cent is, however, rather difficult and requires complex strain microscopy. In this study micro bridges are investigated, where strain enhancement in about 0.2 % tensile pre-strained Ge layers grown on Si is achieved. The transfer of an electron- beam written pattern leads to force field concentration. By tuning the geometry of the structure, the strain may be enhanced to levels high enough to convert the indirect band gap to a direct one. The strain distribution in tensile strained Ge micro-bridges is studied by X-ray nano-diffraction, which is an excellent tool to spatially resolve the 3D displacement field. The strain mapping of the transition regions between the centre of the bridge and the wide feeder arms was performed at beamline ID01 of the ESRF. Single bridges were raster-scanned in real space, while Ge Bragg peaks were recorded in 3D. This allows to map Bragg peaks with a resolution close to the beamsize and thereof to quantify the strain in the bridges with a spatial resolution of around 300 nm. These results, together with finite-element calculations, will be used to understand strain limitations of Ge and hence its lasing potential, establishing an important milestone in the development of Si-CMOS compatible laser sources.

154 POS-23, FKP & NESY, Wed, 17:45 Magnetic study of iron oxide nanoparticles dispersed within porous silicon Petra Granitzer1, Klemens Rumpf1, Puerto Morales2, Peter P¨olt3, Michael Reissner4

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2CSIC Madrid, Serrano, 117. 28006 Madrid, Spain 3Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria 4Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Wien, Austria

Iron oxide nanoparticles (NPs) of 3.8, 5 and 8 nm have been infiltrated into the pores of porous silicon. The aim is to create a superparamagnetic (SPM) nanocomposite system with maximized magnetic moment. Therefore the particle size versus the superparamagnetic behaviour has been figured out. The blocking temperature TB which indicates the transition between SPM behaviour and blocked state is not only dependent on the particle size but also the magnetic interactions between them which can be varied by the distance between the particles. Thus a modification, on the one hand of the pore-loading and on the other hand of the porous silicon morphoplogy results in a composite material with a desired TB. Because both materials, the mesoporous silicon matrices as well as the Fe3O4-NPs offer low toxicity the system is a promising candidate for biomedical applications as e.g. magnetic field guided drug delivery.

POS-24, FKP & NESY, Wed, 17:45 High Resolution X-Ray Diﬀraction Studies on Arrays of SiGe Islands Nina Hrauda1, Jianjun Zhang2, Heiko Groiss1, Tanja Etzelstorfer1, Vaclav Holy3, Julian Stangl1, G¨unther Bauer1 1Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria 2IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany 3Charles University Prague, Ke Karlovu 5, Praha, 12116, Czech Republic

The Si-Ge material system is an interesting topic for both for basic research advanced nanoscale devices as well. To speed up silicon-based transistors both tensile (for n-type) or compressive strain (for p-type) can be applied to the Si-channel of MOSFETs, depending on the setup. Several approaches exist to induce that strain like the application of stressed nitride layers or the use of planar SiGe stressor structures. Our research focuses on the use of epitaxially grown 3D SiGe islands that occur due to the lattice mismatch of 4.2% between Si and Ge. We present studies based on X-ray diffraction and finite element method modeling including both dome- and barn-shaped SiGe islands grown on prepatterned Si(001) substrates. The overgrowth of highly relaxed SiGe islands with Si results in tensile strain in the Si layer above the buried island. The amount of strain depends on several factors such as the composition of the buried island, its shape, as well as the thickness of the capping layer. Growing SiGe islands in a closely-spaced configuration can be used to induce compressive strain in the sections of the Si cap layer situated between those islands.

155 POS-25, FKP & NESY, Wed, 17:45 Proton implanted silicon wafers investigated by electron beam induced current measurements Stefan Kirnst¨otter1, Peter Hadley1, Werner Schustereder2, Martin Faccinelli1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Inﬁneon Technologies Austria AG, 9500 Villach, Austria

Electron Beam Induced Current (EBIC) is an analysis method used in a Scanning Electron Microscope (SEM) to investigate buried junctions or defects in semiconductors. During an EBIC measurement, the electron beam enters a semiconductor and generates electron-hole pairs. If the charge carriers diffuse into a region where there is a built-in electric field, such as a pn junction or a Schottky contact, charge separation will occur and a current will flow. This is similar to what happens in a solar cell except in an EBIC measurement the electron-hole pairs are generated by the electron beam instead of by light. We have used EBIC to investigate proton implanted silicon wafers with implantation doses from 1 × 1013 p+/cm2 to 1 × 1015 p+/cm2 and with implantation energies from 500 keV to 5 MeV. The implantation introduces vacancies, silicon interstitials, and hydrogen into the crystal. The sample is then annealed in the temperature range from room temperature to 1000◦C and defect complexes form. The microscopic structure of these defect complexes is not completely understood. There is a class of oxygen-vacancy defect complexes called thermal donors that are known to act as donors in silicon. Since electron-hole pairs recombine at defects, the EBIC signal is decreased if the charge carriers have to diffuse past defects on their way to the measurement contacts.

POS-26, FKP & NESY, Wed, 17:45 Towards kinetic Monte-Carlo simulations with ab initio accuracy Martin Leitner1, Tobias Kerscher1, Stefan M¨uller2, Raimund Podloucky1

1University of Vienny, Sensengasse 8/7, 1090 Vienna, Austria 2Hamburg University of Technology, Denickestrasse 15 (K), 21073 Hamburg, Germany

For the Ni–Pt and Fe–Cu alloy system we present the first steps towards kinetic Monte-Carlo (KMC) simulations with ab initio accuracy. Many body interactions which describe the energetics of both the local minima and migration states are included by cluster expansions (CE) in the framework of the UNCLE code [1]. In this model approach single atoms jump to vacant nearest-neighbor sites and have to overcome configuration dependent migration barriers. According to transition state theory (TST) jump rates are then derived by the energy difference between initial and saddle point state. The KMC simulations require a) vacant lattice sites, which enforce a ternary CE for a binary compound, and b) the configuration dependent height of the saddle points, which have to be calculated and included in the CE. We discuss different aspects of jump profiles in the respective systems computed by density functional theory (DFT) calculations. The support of FWF project 4110 (ViCoM) is acknowledged. [1] D. Lerch et al., Modelling Simul. Mater. Sci. Eng. 17 (2009), 055003

156 POS-27, FKP & NESY, Wed, 17:45 Wood templated inorganic nanoporous materials: Formation and water adsorption studied by in situ SAXS experiments Roland Johann Morak1, Gerhard Fritz-Popovski1, Daniel Van Opdenbosch2, Cordt Zollfrank2, Barbara Aichmayer3, Oskar Paris1

1MontanuniversitätLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria 2Technische UniversitätMünchen,Schulgasse 16, 94315 Straubing, Germany 3MPI of Colloids and Interfaces, Wissenschaftspark Potsdam-Golm, 14424 Potsdam, Germany

Wood is an abundantly occurring hierarchically structured composite material. It consists of fibrils of diameter 10-20 nm, which are embedded into a lignin matrix. These fibrils consists themselves of cellulose microfibrils of diameter 2-3 nm embedded in surrounding hemicelluloses. In this work, wood was used as a template in order to obtain inorganic materials with chiral nano- pores. The necessary preparation steps are deliginification, cell-wall modification with maleic acid anhydride, infiltration with tetraethyl orthosilicate (TEOS) and calcination. We studied the trans- formation of the composite material to porous silica using synchrotron radiation for in-situ SAXS experiments during the calcination of the sample. The nano-structure changed progressively from fibrils with a nearly homogeneous electron density and with a diameter of 10-20 nm to fibrils with diameters of 8-10 nm. Modeling of the results revealed a two step process. The hemicelluloses dis- integrate at 200-300 ◦C and amorphous silica is formed. The cellulose fibrils, which are embedded in amorphous silica after this step, are still intact. At 300-400 ◦C the cellulose degrades and leaves nanometer sized pores within the silica. The gas adsorption properties of these materials were studied further by in-situ adsorption experiments with SAXS and compared to results obtained from gravimetric measurements. The gravimetric measurements feature the existence of accessible pores whereas the scattering parameters imply a change of the material structure during a sorption cycle.

POS-28, FKP & NESY, Wed, 17:45 Polarisation-dependent Raman characterization of stibnite (Sb2S3) Maurizio Musso1, Paolo Sereni1, Kurt Krenn2, Peter Knoll1, Peter Blaha3, Karlheinz Schwarz3, G¨unther Schmidt3 1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria 2University of Graz, Universit¨atsplatz2, 8010 Graz, Austria 3Vienna University of Technology, Getreidemarkt 9/165-TC, 1060 Vienna, Austria

Single crystal samples of Stibnite (Sb2S3), a naturally occurring sulﬁde mineral with semiconducting properties (band gap 1.72 eV), were studied by polarization-dependent Raman spectroscopic measurements using both visible and NIR laser excitation. In the case of visible laser excitation at 532 nm (2.33 eV) the laser light was highly absorbed, being the photon energy higher than the band gap of the semiconductor; measurements at 180◦ scattering geometry (backward scattering) were therefore only possible. In the case of NIR laser excitation at 1064 nm (1.17eV) the photon energy was lower than the band gap of the semiconductor, the sample therefore resulting transparent to the excitation line, therefore allowing polarization-dependent measurements both in 180◦ and 90◦ scattering geometry. The analysis of the group symmetries yields 10 Ag, 5 B1g, 10 B2g, and 5 B3g Raman active vibrational modes. The comparison of the corresponding Raman frequencies calculated using the ab-initio WIEN2k and PHONON codes [1] with our experimental values obtained both in 90◦ and in 180◦ scattering geometries shows overall good qualitative agreement, although the discrimination between Ag and B2g modes, and that between B1g and B3g modes in the experimental spectra is still challenging, since the number of bands is the same for both modes, and the calculated band positions quite close. [1] P. Blaha, K. Schwarz, G.K.H. Madsen, D. Kvasnicka, J. Luitz, WIEN2k (2001) ; K.Parlinski, Software PHONON, Cracow (2002).

157 POS-29, FKP & NESY, Wed, 17:45 Numerical simulations of scanning gate experiments in the quantum Hall eﬀect regime Josef Oswald1 1Montanuniversit¨atLeoben, Franz-Josef-Strasse 18, 8700 Leoben, Austria

In combination with the scanning gate microscope (SGM), the quantum Hall (QH) system provides a possibility for studying transport in coherent electronic systems. A gate tip introduces a local distortion and the response of the device is recorded versus tip position. We use a non- equilibrium network model (NNM) for transport and combine it with a full quantum mechanical many particle calculation of the disordered electron system on the Hartree-Fock level. The disordered potential of the electronic system can be understood as a native random arrangement of quantum dots and quantum point contacts, which interact in a complex way. Either caused by a sweeping magnetic field or by moving a biased gate tip, any changes of the quantum states are sensitively monitored also by the Hartree part of the self-consistent Hartree-Fock solution, which modulates the transmission behaviour of the involved saddle potentials. That is sensitively detected by our network model and results e.g. in resistance fluctuations. We present preliminary simulation results for both, magneto resistance fluctuations and responsivity maps for a moving gate tip. The importance of the electron-electron interaction in our simulations is demonstrated by turning on and off the Hartree part of the Hatree-Fock solution for the screened random potential. Financial Support: Austrian Science Foundation FWF Project.Nr. P19353-N16

POS-30, FKP & NESY, Wed, 17:45 The nanomechanics of feather keratin studied by small-angle X-ray scattering Silvia Pabisch1, Ingrid Weiss2, Helmut Kirchner2, Stephan Puchegger1, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria 2INM – Leibniz-Institut f¨urNeue Materialien gGmbH, Campus D2 2, 66123 Saarbr¨ucken,Germany

Feather keratin is a highly conserved protein of 98 amino acids synthesized intracellularly in aves. In the cortex of the tail covert feathers of the peacock it forms a crystalline structure, held together by disulfide bonds between the nine cysteines of the molecule. Despite the biological importance of the molecule, its spatial structure has not yet been determined. Fraser and Parry proposed a crystallographic arrangement of beta-barrels and relegate the N-terminus and the C- terminus to an amorphous matrix, akin to the situation in silk [1]. Therefore, in-situ tension and compression tests were made to investigate the changes in axial and lateral direction. Nanoscopi- cally a pronounced structural asymmetry between tension and compression rules out a dihedral axis normal to the fibril direction, and indicates a strong clip-like polarization of the molecule. Based on these X-ray diffraction data from Pavo cristatus feathers, a model is presented for the axial and lateral arrangement of the molecule in feather keratin, which integrates biochemical structure and mechanical experiments. [1] R. D. B. Fraser, D. A. D. Parry, J. Struct. Biol. 162 (2008) 1-13.

158 POS-31, FKP & NESY, Wed, 17:45 Fabrication and optical characterization of CdSe quantum dots Manuel Pacheco1, Carlos Rudamas1

1Universidad de El Salvador, Escuela de F´ısica, 25 San Salvador, El Salvador

In this paper we present results of the optical characterization of CdSe quantum dots (QDs) fabricated using the thermal decomposition technique. For the preparation of the samples we used two precursor solutions to generate the reaction which was initiated at a temperature of 225◦C. Ten aliquots were collected at diﬀerent time intervals during the synthesis. The optical properties of these samples have been studied by absorption spectroscopy and photoluminescence spectroscopy. The maximum of the absorption bands show a shift to lower energies from 2.95 eV to 2.35 eV as the size of the quantum dots increase. Photoluminescence bands also exhibit a similar shift from 2.66 eV to 2.17 eV. Stokes-Shifts from 20 nm to 40 nm were estimated. The full width at half maximum (FWHM) obtained for the photoluminescence bands ranges from 30 nm to 45 nm, which indicates a very good mono-dispersivity of the samples. To calculate the size of the quantum dots we used the eﬀective mass approximation and the absorption spectra for each sample. Quantum dot radii obtained by using this model vary from 1.73 nm to 2.49 nm.

POS-32, FKP & NESY, Wed, 17:45 Defects in an iron-nickel meteorite examined with positrons Peter Parz1, Matthias Leitner1, Wolfgang Sprengel1, Werner Puﬀ1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

A typical iron-nickel meteorite (Gibeon) with a composition of Ni 7,93 wt-%, Co 0.41 wt-%, P 0.04 wt-%, 91.62wt-% Fe and small amounts of carbon, was investigated by positron annihilation methods (positron lifetime spectroscopy and coincidence Doppler broadening). This meteorite exhibits the typical Widmanstättenstructure, a two-phase microstructure of Fe-rich Kamacite and Ni-rich Taenite, which is formed due to unique cooling rates of about approximately 35K per one million years. Upon the low cooling rates in space and the formation of the Widmanstätten structure, the meteorite sample was expected to be in equilibrium condition and free of defects. However, a high mean positron lifetime was observed, which derives from open volume defects. The meteorite samples were then gradually heated in a high-vacuum furnace, cooled down to room temperature and probed. The temperature treatment leads to a decrease of the mean positron lifetime, as well as a gradual evolution of the 2d-DB spectra towards pure iron. This results lead to the conclusion, that in the progress of the formation of the Widmanstättenstructure open volume defects are introduced. Upon heat treatment these defects start to dissolve and do not re-appear. We attribute these open volume defects to misfit dislocations between the Kamacite (Ni-poor) and Taenite (Ni-rich) structures.

159 POS-33, FKP & NESY, Wed, 17:45 Negative thermal expansion of carbon crystallites measured in single carbon ﬁbres Harald Rennhofer1, Stephan Puchegger1, Silvia Pabisch1, Stefan Siegel2, Chenghao Li2, Oskar Paris3, Herwig Peterlik1

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria 2Max-Planck Institute of Colloids and Interfaces, 14424 Potsdam, Germany 3Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

In-situ X-ray scattering experiments on single carbon fibres have been performed at BESSY Berlin. The structural response to simultaneous application of temperature and load was studied by Small- and Wide Angle X-ray Scattering, respectively. In this work the thermal expansion of the crystallites in the carbon fibres (MPP and PAN) is presented. At temperatures below 800 ◦C negative thermal expansion in the graphite planes was measured for the MPP fibres. The relationship with the macroscopic thermal expansion is given by the misalignment of the crystallites with respect to the fibre axis i.e. the degree of graphitization.

POS-34, FKP & NESY, Wed, 17:45 Toward polarisation entangled photon pairs from microcavity exciton polaritons Mathias Sassermann1, Lukas Einkemmer1, Patrick Mai1, ZoltánVörös1, Gregor Weihs1, Tobias Zederbauer2, Hermann Detz2, Aaron Maxwell Andrews2, Gottfried Strasser2, Christian Schneider3, Andreas Löffler3, Sven Höfling3, Alfred Forchel3, Stefano Portolan4

1University of Innsbruck, Technikerstrasse 13, 6020 Innsbruck, Austria 2Vienna University of Technology, Karlsplatz 13, 1040 Vienna, Austria 3UniversitätWürzburg, Am Hubland, 97074 Würzburg, Germany 4Institut Néel-CNRS,25 avenue des Martyrs, BP 166 38042 Grenoble, Cedex 9, France

The strong coupling of photons and quantum well excitons in semiconductor microcavities leads to the formation of new quasi particles called polaritons. Due to their peculiar dispersion curve and the convenient experimental accessibility microcavity polaritons have gained considerable interest in the recent years. Polariton states can be selectively populated by choosing the excitation angle and the wavelength of the excitation laser. After a lifetime of a few picoseconds the polariton decays and a photon is emitted from the cavity. This photon carries the whole information on the previous polariton state.So far the focus in this field was mainly on polariton lasing, BEC, non-classical correlations and collective phenomena in semiconductors. Recent theoretical studies suggested utilizing polariton-polariton scattering for generation of entangled photon pairs. S.Portolan et al.(EPL 88 20003 (2009)) have proposed a scheme based on polariton four-wave mixing in order to generate polarisation entangled photon pairs. The experimental implementation of this scheme requires two pump beams with different incidence angles and wavelengths. For this purpose we employ a multidimensional spectroscopy setup based on two spatial light modulators (Appl. Phys Lett. 100 072109 (2012)). As a first step towards polariton entanglement parametric polariton scattering under two-colour excitation has to be established. In this contribution we will show first results on such scattering experiments and will demonstrate the feasibility of the proposal in Portolan et al. The experimental results will be compared to detailed numerical simulations based on a Langevin master equation approach.

160 POS-35, FKP & NESY, Wed, 17:45 Elektromagnetische Levitation – Berührungsfreie Untersuchung von flüssigemMetall an der TU Graz Alexander Schmon1, Kirmanj Aziz1, Gernot Pottlacher1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

FlüssigesMetall als Untersuchungsobjekt stellt besonders hohe Ansprüche an den experimentellen Messaufbau um dem Prinzip der Interaktionsreduktion als Messvoraussetzung gerecht zu werden. Die Methode der Elektromagnetischen Levitation ermöglicht eine tiegelfreie Bestimmung von thermophysikalischen Eigenschaften metallischer Schmelzen. Derzeit wird der Aufbau einer entsprechenden Apparatur am Institut fürExperimentalphysik der TU Graz fertiggestellt. Dabei werden durch ein inhomogenes elektromagnetisches Hochfrequenzfeld Wirbelströmeim Proben- material erzeugt, welche aufgrund der ausgeübtenLorentzkraft ein frei schwebendes Positionieren der Probe ermöglichen und gleichzeitig zu einem Aufheizen des Probenmaterials bis in die flüssige Phase führen. Die Probentemperatur wird optisch durch pyrometrische Messung bestimmt und gleichzeitig die Probengeometrie mittels zweier High-Speed-Kameras aufgezeichnet. Unter Verwen- dung dieser Messgrößenwird die Bestimmung von Dichte und Oberflächenspannung der Probe in Abhängigkeit von der Temperatur ermöglicht. Das Projekt Messung von Oberflächenspannung und Dichte mittels Levitation wird vom Fonds zur Förderungder wissenschaftlichen Forschung (FWF) gefördert- Projekt P 23838-N20

POS-36, FKP & NESY, Wed, 17:45 Polarization-dependent Raman characterization of Stibnite (Sb2S3) in the temperature-range 290K-77K Paolo Sereni1, Maurizio Musso1, Stefan Volgger1, Christoph Oberauer1, Peter Knoll2

1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria 2University of Graz, Universit¨atsplatz5, 8010 Graz, Austria

A complete set of measurements of the polarization-dependent Raman spectra of Stibnite (Sb2S3) in the temperature range from 290K to 77K are here presented and compared with those obtained in our previous activities [1]. The used equipment consisted of a 1064 nm polarized laser excitation, an FT-Raman spectrometer (Bruker IFS66 + FRA106) and an Optistat LN2 Bath Cryostat (Oxford Instruments). [1] P. Sereni et al., AIP Conference Proceedings 1267, 1131-1132 (2010)

161 POS-37, FKP & NESY, Wed, 17:45 Modeling disorder in self-assembled monolayers with embedded dipoles Manuel Vieider1, Luca Muccioli2, Otello Roscioni2, Egbert Zojer1, Michael Zharnikov3, Claudio Zannoni2, Martin Stolterfoht1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Universit´adi Bologna, Viale Risorgimento 4, 40136 Bologna, Italy 3University of Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany

We present a study using several techniques to simulate self assembled monolayers (SAM) on the Au(111) substrate. Accurate quantum mechanical simulations were used to parameterize the charge distribution on the molecules and to estimate the charge transfer to the gold surface caused by the binding of sulfur atoms. The results delivered the inputs for atomistic molecular dynamic simulations carried out with the LAMMPS code. The intermolecular interactions were described by the CHARMM27 force field, while for the interaction of the molecules and the gold atoms different force fields were tested. The main focus of this work is to provide an accurate description of the morphology of alkylthiols with and without a mid-chain ester functionalization. This particular class of molecules was chosen because the ester group provides an intramolecular electric dipole moment at a certain distance from the surface. We calculated the distribution of dipole orientations from equilibrated structures of monolayers in order to estimate the net-potential shift induced by those dipoles. Also, different surface coverages have been simulated to investigate the thermodynamic mechanisms of SAM islands formation and to quantify the intrinsic structural disorder by computing various order parameters.

POS-38, GEP, Wed, 17:45 Alfred Wegener: Second Expedition to Greenland - A photographic window to the past Martin Leitner1, Sabine Tschürtz1, Gottfried Kirchengast1, Heinrich Kranzelbinder2, B. Prügger2, Reinhard Krause3, M. Kalliokoski4, Ester Thórhallsdóttir5

1University of Graz (WEGC UniGraz), Leechgasse 25, 8010 Graz, Austria 2Steierm¨arkisches Landesarchiv, Karmeliterplatz 3, 8010 Graz, Austria 3Alfred Wegener Institute, Columbusstrasse, 27568 Bremerhaven, Germany 4University of Turku, FI-20014 Turku, Finland 5Fj¨olbrautask´li Snæfellinga, Iceland

On several expeditions to Greenland, Alfred Wegener (1880-1930) collected scientiﬁc data and took pictures on glass plates from landscapes and glaciers, the expedition equipment, the people and animals taking part on the expeditions as well as physical phenomena as dust storm, clouds or spherical light phenomena. Until the tragic end of the expedition in 1930, Wegener was professor at the University of Graz, and such a stock of about 300 glass plates stayed there. Chronologically the plates show the Danmark Expedition 1906-1908, the crossing of Greenland expedition with stop in Iceland 1912-1913, and the German Greenland Expedition 1929-1930. This presentation gives an overview of pictures and dates from the Second Greenland Expedition, leaded by J.P.Koch in 1912-1913. The aim of our work is to digitize all the plates for further studies. We present a selection from the second Greenland expedition, with the stopover in Iceland. For those made at Iceland in 1912 we present a comparison between past pictures an new one from the same viewing point made in 2011.

162 POS-39, LHS (PUS), Wed, 17:45 Kinder reisen durch die Wissenschaft Hans Eck1, Sabine Hirschmugl-Gaisch2

1Kirchliche Pädagogische Hochschule Graz, Lange Gasse 2, 8010 Graz, Austria 2Kindergarten Rosental an der Kainach, Hörggasstrasse 50, 8582 Rosental “Kinder reisen durch die Wissenschaft” ist ein Gemeinschaftsprojekt der Neuen Mittelschule Voitsberg, des Kindergarten Rosental a. d. K. , dem “Offenen Labor Graz” in Kooperation mit der “7. fakultät”der Karl-Franzens-UniversitätGraz und dem InterdisziplinärenZentrum fürFachdi- daktik der Pädagogischen Hochschule Steiermark, mit dem Ziel, Kindern, wie Jugendlichen einen kreativ-interessanten und lustvoll-aktiven Zugang zu den unterschiedlichen naturwissenschaftlichen Disziplinen und Fachrichtungen zu ermöglichen. Unter dem Motto: “Große helfen Kleinen” werden in diesem Projekt Forschungsteams bestehend aus je einem Kindergarten-Kind und einem/er SchülerInder Neuen Mittelschule gebildet, die auf dieser Reise durch die verschiedensten wissenschaftlichen Institutionen gemeinsam Aufgaben lösen,Experimente durchführenund dabei die Möglichkeit haben, ihre eigenen Forschungen zu betreiben. Betreut und angeleitet werden die Kinder und Jugendlichen in den einzelnen Modulen dabei jeweils von einem Wissenschaftler, oder Spezialisten seines Faches und einem/er StudentIn der naturwissenschaftlichen Fachrichtung. Den Auftakt der “Reise durch die Wissenschaften” bildete der erste “Molekulare Kochkurs fürKinder- gartenkinder” in Begleitung von SchülerInnender NMS- Voitsberg unter dem Motto: “Es dampft aus Kochtopf, Mund und Nase” an der NMS-Voitsberg. Unter der Anleitung von 2- Haubenkoch Heinz Preschan, Dr. Helmut Jungwirth (Offenes Labor Graz) und einer Studentin der Biowis- senschaften wurden in 3 Teams nicht nur dampfender, flüssigerStickstoff und seine Auswirkungen auf Popcorn, Petersilie und Basilikum erforscht, sondern auch Joghurt-Bomben, Chilli-Rosmarin- Lollies und Kürbiskernschokolade hergestellt und mit großem Genuss gemeinsam verkostet.

POS-40, LHS (PUS), Wed, 17:45 Forschendes Lernen als Methode der Kompetenzf¨orderung Erich Reichel1, Eduard Schittelkopf1, Veronika Rechberger1

1Pädagogische Hochschule Steiermark, Hasnerplatz 12, 8010 Graz, Austria Fürden Kompetenzerwerb im Physikunterricht bietet sich das forschende Lernen als hilfreiche Lernumgebung an. Es ermöglicht den Lerndenden an geeigneten Experimenten eigene Erfahrun- gen zu machen. Dadurch wird ihr Interesse am Thema geweckt und Raum füreigene Gedanken und Lösungsvorschlägeim Unterricht geschaffen. Durch den wiederholten Einsatz im Unterricht könnenTeile der Handlungsdimension des österreichischen Kompetenzmodells vor allem im Bereich “Erkenntnisse gewinnen” abgedeckt werden. Vermittelnder Unterricht, in dem das Wissen als Pro- dukt gesehen, das von der Lehrperson an die Lernenden weitergegeben wird steht dem forschenden Unterricht gegenüber, in dessen Rahmen Wissen als ein Prozess gesehen wird, in den der lernende Mensch eintaucht. Im Rahmen von forschendem Unterricht stoßen die Lernenden dabei auf Fra- gen, die bei Durchführungdes vermittelnden Unterrichts nie auftreten würden. Von uns wird vierphasiger Unterrichtszyklus vorgeschlagen: Phase 1: Den Lernenden wird das Experiment vorgeführtund die Protokollierung ihrer Beobach- tungen eingefordert. Phase 2: Die Lernenden führendas Experiment selbst durch und fixieren ihre Beobachtungen schriftlich. Phase 3: Die Beobachtungen führenzur Formulierung eigener Forschungsfragen. Phase 4: Die Lernenden planen und bearbeiten ihr eigenes Experiment oder eine darauf auf- bauende Variation des Experiments zur Beantwortung ihrer persönlichen Forschungsfrage. Fürdie Dokumentation der Arbeiten durch die Lernenden und Uberprüfungdes¨ Lernfortschrittes wurde ein eigener Protokollraster entwickelt. Unterrichtsbeobachtungen zeigten in unterschiedlichen Klassen auf unterschiedlichen Schulstufen, dass diese Methode zu mehr Eigenständigkeit und damit eine Kompetenzsteigerung der Lernenden bewirkt.

163 POS-41, LHS (PUS), Wed, 17:45 Mit Magnetfeldern h¨oren Engelbert Stuetz1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria

Am Projekt “Mit Magnetfeldern hören”arbeiteten alle Schülerinnenund Schülerzweier siebten Klassen mit. Ausgangspunkt des Projekts war diese Problemstellung: Trotz ihres Hörgeräteshaben schwerhörigeMenschen oft große Probleme, einen Sprecher zu verstehen. Das kann im Kino, im Theater, bei Vorträgenoder auch im Klassenzimmer der Fall sein. Schuld daran ist die Funktions- weise des Hörgerätes.Es macht nicht nur Erwünschtes lauter, sondern auch Nebengeräusche. Die Person hörtnur noch ein Stimmgewirr und ist kaum mehr in der Lage, daraus die wichtigen Informa- tionen zu filtern. Die Lösungist eine einfache Anlage, die im Raum aufgebaut wird. Sie überträgt die Information mit Hilfe eines Magnetfeldes unmoduliert zur Telefonspule des Hörapparates. Das Projekt hatte diese Schwerpunkte: • Eigenbau einer Induktionsanlage füreinen großen Raum (Physiksaal) • Klärungdes physikalischen Hintergrundwissens zur Funktion der Induktionsanlage. Im Wesent- lichen beschäftigten wir uns damit, wie man mit Magnetfeldern das Hörenverbessern kann. • Bau von Lern- und Experimentierstationen füreine Ausstellung “Explorama”. Wichtiger Be- standteil jeder Station war ein von Schülernausgearbeitetes Arbeitsblatt zum Thema der jeweiligen Station. • Das Explorama in Betrieb: Eine Woche lang konnten Schulklassen fürjeweils eine Stunde das Explorama buchen. Die Lern- und Experimentierstationen waren dabei von Schülernder Projekt- klassen betreut. • Die Evaluation zum Abschluss des Projekts gab uns Auskunft über den Erfolg des Projekts und über Verbesserungsmöglichkeiten bei zukünftigenähnlichen Projekten an der Hamerlingschule.

POS-42, LHS (PUS), Wed, 17:45 Papier erleben Stefanie Anna Tritthart1, Beatrix Janits1

1HS 1 Deutschlandsberg, Schulgasse 16, 8530 Deutschlandsberg, Austria

“Papier ERLEBEN” - das war das Thema des Projektes, an dem von November 2011 bis Jänner2012 an der Hauptschule I in Deutschlandsberg gearbeitet wurde. Nicht nur die Physik- und Chemiestunden in diesem Zeitraum werden den Schülerinnenund Schülernsicherlich längere Zeit in Erinnerung bleiben. Auch in den Schwerpunktgruppen der 7. und 8. Schulstufe wurde sehr intensiv an diesem Projekt gearbeitet. Die Highlights waren einerseits das Herstellen von handgeschöpftemPapier aus unterschiedlichen Materialien und Beigaben wie z.B. das Wespenpa- pier, andererseits die zahlreichen Versuche, die mit diesem Papier gemacht wurden. Es wurden beispielsweise verschiedene Papiersorten, darunter auch selbstgeschöpftesPapier, auf eine Herd- platte gelegt und genau beobachtet bzw. gemessen wann welches Papier verbrennt. Das “Material” Papier wurde in den Wahlpflichtfächern in den dritten und vierten Klassen unserer Schule unter die Lupe genommen und zur Herstellung unterschiedlichster Dinge verwendet, wie z.B. zum Bau von Papierflugzeugen und abgestumpften Ikosaedern (besser bekannt als Fußbälle)oder zur Herstellung von in Origami-Technik gefalteten Figuren. Eine Gruppe (Schwerpunkt Kunst) beschäftigtesich damit, Sessel mit Papiermosaiken zu überziehen. Im Zuge des technischen Schwerpunkts haben die Schülermit Hilfe der Lego Mindstorms c Roboter das Wort “Papier” auf Papier geschrieben, wobei der Bau des Stifte-Halters und die Programmierung der einzelnen Buchstaben eine ganz schöne Herausforderung fürdie einzelnen SchülerInnenwar. Der krönendeAbschluss war die Präsentation des Projektes, bei der die Kreativitätunserer Schülerinnenund Schülergefragt war. Nicht die bei der Projektarbeit entstandenen Produkte allein, sondern auch das neu erworbene Wissen war Mittelpunkt der ansprechenden und gelungenen Präsentation.

164 POS-43, MBU, Wed, 17:45; This poster will also be presented on Thu. 20th September 2012, 16:45 - 16:50; Ground based MAX-DOAS observations of tropospheric trace gases in San Salvador, El Salvador Carlos Armando Alberti1, Benjamin Levy Mendoza1, Carlos Rudamas1

1Universidad de El Salvador, Escuela de F´ısica, 25 San Salvador, El Salvador

High levels of air pollution in different Central Americas capital cities were reported a few years ago, being San Salvador metropolitan area the place with the highest concentration values of several pollutants. The high levels of these pollutants, in some measuring points, exceed the limit values established by the environmental law of the republic of El Salvador and also those established by EPA and WHO. In this work we report on levels of HCHO, O4 and NO2 obtained by using ground based Multi-Axis Differential Absorption Spectroscopy (MAX-DOAS) during a campaign performed in San Salvador on February 2011. The experimental set-up used in the DOAS-measurements consists of a home-made-telescope coupled to an spectrometer by using an optical fiber. The spectral resolution is around 1.2 nm. The diurnal behavior of NO2-dSCD during the working days is characterized by an strong increase in the morning. It could be associated to emissions from vehicles during the rush hours. The obtained dSCD values for HCHO are similar to the obtained by other authors in cities with higher population. The oxygen dimer O4 levels were also measured in order to estimate the aerosol extinction. Similar trends are observed for HCHO and O4. These results could be explained by a change in the aerosol extinction and meteorological conditions.

POS-44, MBU, Wed, 17:45; This poster will also be presented on Thu. 20th September 2012, 16:35 - 16:40; Bioequivalent Solid-State Dosimetry: Current Trends and Future Developments Michael Hajek1

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria

Significant progress in radiobiology has refined our understanding of radiation-induced biological response at the cellular level and challenged the conventional macroscopic description of radiation action in favour of a nanodosimetric approach, which considers the spatial distribution of energy deposition along the particle track. The empirical correlation of luminescence properties of alkali halides and biological endpoints, such as DNA strand breaks in human fibroblasts, open up promising opportunities for bioequivalent solid-state dosimetry. Analysis of the nanodosimetric response to different radiation modalities using track structure theory and general multi-target, multi-hit models makes evident that the targets for radiation-induced effects in physical and biological systems are of comparable size. Availability of bio-equivalent dosimeters would represent a major progress in radiation protection, radiation biophysics and medical radiation physics, for it would allow to evaluate the biological effectiveness of radiations of different quality, largely independently of dose and dose rate. As a consequence, these studies directly support the development of new radiation protection concepts and thus concern a broad spectrum of applications ranging from environmental physics, medical diagnosis and therapy to human space exploration.

165 POS-45, MBU, Wed, 17:45; This poster will also be presented on Thu. 20th September 2012, 16:30 - 16:35; Review and Cross-comparison of Matroshka Phantom Measurements in Different Compartments of the International Space Station Christina Hofstätter1, Michael Hajek1, Thomas Berger2, PawelBilski 3, Daniel Matthiä2, Monika Puchalska4, Andrea Zechner1, Günther Reitz2

1Vienna University of Technology, Stadionallee 2, 1020 Vienna, Austria 2German Aerospace Center, Linder Höhe,51147 Köln,Germany 3The Henryk Niewodniczaski Institute of Nuclear Physics, 152 Radzikowskiego Str., 31-342 Kraków,Poland 4Chalmers University of Technology, SE-412 96 Gothenburg, Sweden

Astronauts working and living in space are exposed to considerably higher doses and different qualities of ionizing radiation than people on ground. Matroshka, a European Space Agency experiment under coordination of the German Aerospace Centre, is the most comprehensive effort so far in radiation protection dosimetry in space using an anthropomorphic upper torso phantom known from radiotherapy treatment planning to map the dose distribution throughout a simulated human body on board the International Space Station (ISS). Absorbed dose and dose equivalent measured by nuclear track detectors and miniature thermoluminescence dosimeters embedded in a regular grid and at the site of vital organs are combined with detailed numerical models to allow for estimation of effective dose. Monte Carlo simulations using the transport codes FLUKA and GEANT4 that provide calculations of particle fluence and dose for various radiation environment conditions further support the experiment and improve cancer risk projections for future long-term space exploration beyond the Earths magnetosphere. The paper presents a review and cross-comparison of data acquired during four missions between January 2004 and March 2011, in which the phantom has been installed in different compartments of the Russian and Japanese segments of the ISS: outside and inside Zvezda, inside Pirs and inside Kib¯o.

166 POS-46, MBU, Wed, 17:45; This poster will also be presented on Thu. 20th September 2012, 16:40 - 16:45; Korrelation relativer Feuchte und Stromumwandlungskoeﬃzient der D¨unnschicht-Photovoltaik Maryam Nikbakhti1, Marcus Rennhofer1, Viktor Schlosser1, Karl Berger2, Philipp Weihs3, Jochen Wagner3, Roman Leidl2, Dietmar Baumgartner4

1University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria 2AIT Austrian Institute of Technology GmbH, Giefinggasse 2, 1210 Vienna, Austria 3University of Natural Resources and Life Sciences, Peter Jordan Strasse 82, 1190 Vienna, Austria 4Observatory Kanzelhöhe,KFU-Graz, Treffen 9521, Austria

Im Rahmen des nationalen Projektes PV-SPEC wurden an klimatisch und meteorologisch unterschiedlichen Standorten verschiedene Modultypen (Mono, CdTe und a-Si) hinsichtlich ihres Verhaltens bezüglich spektraler Anderungen¨ des einfallenden Sonnenlichtes und meteorologischer Parameter untersucht. Schlussfolgerungen über die Umwandlungseffizienz der Module konnten getroffen werden. Dazu wurden Module jeder Type mit 35◦ Neigungswinkel nach Osten, Süden und Westen an einem Hochgebirgsstandort (1600 m) und einem Flachlandstandort (170 m) über einen Zeitraum von 3 Jahren untersucht. Es wurde die Korrelation zwischen den gemessenen Umge- bungsvariablen, der Einstrahlung, den spektralen Bestrahlungsstärkewerten und der Umwand- lungseffizienz η, der Module untersucht. Schwerpunkt der präsentierten Arbeit ist der Einfluss der relativen Feuchtigkeit der Luft sowie globale Einstrahlung – E – und spektral aufgelöste Einstrahlung E(λ) auf elektrischen Parameter und Temperatur, Umgebungsbedingungen. Weit- ers wurde die Stärke der Alterung der Module innerhalb des Messzeitraumes bestimmt. Eine Veränderungder Wetter- oder feuchtebedingten spektralen Anteile der auf ein Modul treffenden Einstrahlung (großteils Rayleigh-Streuung) hin zum “Roten” oder “Blauen” Spektralbereich be- dingt eine unmittelbare Anderung¨ der Umwandlungseffizienz: über die spektrale Empfindlichkeit (SR) beeinflusst eine solche Anderung¨ den im Modul aus dem Licht generierbaren Strom. Es wurden die Einflüsseder relativen Feuchtigkeit auf Bodenniveau in diesem Zeitraum mit jenen der relativen Feuchtigkeit des atmosphärischen Höhenprofilsverglichen. Durch eine Simulation wurden die theoretischen Maximalwerte der Feuchteabhängigkeit mit den gemessenen Werten verglichen. Die Analyse aller Parameter gibt ein Maß fürdie Abhängigkeit der system- und klimarelevanten elektrischen Messgrößen von der relativen Feuchtigkeit der Luft.

POS-47, OGD, Wed, 17:45 AFM investigation of kraft pulp ﬁber swelling in controlled humidity Christian Ganser1, Robert Schennach1, Christian Teichert2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Kraft pulp fibers are wood fibers from softwood, typically spruce and pine, which are the main constituent for so called kraft paper. Kraft paper is used mainly for packaging applications, where a high strength is required. In this work, the swelling behavior of spruce kraft pulp fibers is investigated by atomic force microscopy (AFM). To perform this task, the AFM was equipped with a fluid cell and a setup where the relative humidity inside the fluid cell can be controlled. The setup enables to select any humidity value between approximately 5% and 80% relative humidity. With this setup, a change in surface morphology of the scanned area could be observed. Fur- thermore, the evolution of the characteristic surface wrinkles of dried pulp fibers with increasing humidity was quantified in two different ways. One way is to measure the distance between the surface wrinkles, the other to determine their height. It could be shown that the distance between the wrinkles is increasing, whereas the height is decreasing. This means that the surface is becoming smoother when the fiber is swelling, which is best observed on a completely wet fiber. Supported by Mondi, Kelheim Fibres and the Christian Doppler Research Society, Vienna, Austria.

167 POS-48, OGD, Wed, 17:45 Kinetic Monte Carlo Simulations of Nucleation and Thin Film Growth of Hexaphenyl on Amorphous Mica Christoph Gleichweit1, Adolf Winkler1, Levent T¨umbek1, Karin Zojer1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Ultra-thin films of para-hexaphenyl on sputter amorphized mica(001) exhibit the surprising behavior of forming bimodal island size distributions. Small islands were observed besides bigger ones. It is believed that as long as the sample is in ultra-high vacuum, there exists a 2D-gas phase between the bigger islands, which vanishes by nucleating a lot of small islands when exposed to air. Probably due to the adsorption of water on the surface the energetics of monomers on the surface change and islands form. This behavior is named adsorbate induced subsequent nucleation. Using KMC simulations this effect was tried to be reproduced with the objective of extracting information about the critical cluster size and the island size distributions. For this reason an algorithm for edge hopping that respects also the critical island size was developed. The system initializes by starting with an initial concentration of monomers on the surface. These monomers suddenly start to diffuse and hence nucleate islands with the specified critical nucleus size and diffusion barriers. Particles that are part of stable clusters are not anymore allowed to detach from the islands. The simulation stops as soon as all molecules are incorporated into islands. The resulting island densities were compared to the experimental results. It turned out that a critical island size of i = 7 matches the experiments. Moreover, the island size distributions were compared to the ones obtained from the AFM images and were found to agree qualitatively.

POS-49, OGD, Wed, 17:45 Susceptibility measurements of Ni nanostructures on Cu(110) Michael Hohage1, Mariella Denk1, Richard Denk1, Robert Mittermair1, Daniel Queteschiner1, Lidong Sun1, Peter Zeppenfeld1

1Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria

A set-up capable of in-situ magnetic susceptibility measurements is introduced. The magnetic measurements are based on a Reflectance Difference Spectrometer (RDS), by exploiting its high sensitivity to the polar Magneto-Optic Kerr Effect (RD-MOKE). The external magnetic field is created by a magnetic coil placed in close vicinity of the sample. For susceptibility measurements a sinusoidal magnetic field is applied to the sample. The response of the RD-MOKE signal at photon energies between 1.5 and 5 eV is frequency analyzed and the amplitudes and phases of the first and higher harmonics are obtained. The capability of this set-up is demonstrated for ultra thin Ni films on Cu(110)-(2×1)O. Comparison to regular RD-MOKE shows that the signal-to-noise ratio has been substantially improved. The analysis of the first and higher harmonics allows studying magnetic phase transitions in more detail: The spin reorientation transition (SRT) occurring at a Ni coverage of 9 ML on Cu(110)-(2×1)O and the behavior of Ni-films around the Curie temperature have been investigated and the ferromagnetic and (quasi-)paramagnetic behavior has been identified. In the ferromagnetic regime hysteresis curves have been obtained. The improved signal allows us to investigate the magnetic properties of CoTMPP films on Cu(110)-(2×1)O. At photon energies of 2.7 eV where a strong optical transition occurs also the susceptibility shows a peak. Thus we can clearly correlate the magnetic susceptibility to the optical transitions of the films.

168 POS-50, OGD, Wed, 17:45 Dynamic plowing lithography and 6P thin ﬁlm growth on graphene investigated by atomic force microscopy Markus Kratzer1, Stefan Klima1, Borislav Vasic2, Aleksandar Matkovic2, Andreas Pavitschitz1, Uros Ralevic2, Djordje Jovanovic2, Christian Ganser1, Christian Teichert1, Rados Gajic2

1Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria 2Institute of Physics, Pregrevica 118, P. O. Box 68, 11080 Belgrade, Serbia

For the design of novel graphene based devices specific modifications and manipulations of graphene are essential. The desired properties might be achieved by selective straining and/or multistacking of graphene. As a model system we investigated the growth morphology of the rodlike para-hexaphenyl (6P) molecule on as prepared and dynamic plowing lithography (DPL) modified graphene. As substrate exfoliated graphene flakes on silicon dioxide (SiO2) were used. The DPL of the graphene was performed by bringing the very hard diamond coated tip of a vibrat- ing atomic force microscopy (AFM) probe into close proximity to the substrate. Depending on the chosen experimental parameters the interaction forces between tip and substrate lead either to a local deformation or even to cutting of the graphene flake. The 6P was deposited by means of hot wall epitaxy at sample temperatures above room temperature. The resulting film morphologies on the unaltered and DPL modified graphene were investigated via atomic force microscopy. While on the SiO2 only 6P islands consisting from upright standing molecules are found there are additional needle like structures exclusively found on the graphene.

POS-51, OGD, Wed, 17:45 Morphological investigations of viscose ﬁbers by atomic force microscopy Patrice Kreiml1, Christian Ganser1, Robert Schennach1, Christian Teichert2

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Viscose fibers are used in textiles, hygiene products, and medical applications. The fibers are spun from a viscose solution of cellulose. Their cross-section is shaped by spinning the viscose solution through a spinneret, thus forming the fibers. The water absorption is an important property in the applications mentioned. Here, two samples of viscose fibers were investigated, which showed different behavior under water absorption. The samples were produced under similar conditions and therefore morphological investigations were of interest. In this study, the morphology of samples with high and low water absorption were compared. The surface was investigated by atomic force microscopy (AFM) in tapping mode. A comprehensive roughness analysis, including height-height correlation function (HHCF), showed no significant differences in the roughness parameters. On the surface of all samples, trenches could be observed and further investigation of these trenches was conducted. Depth and length distribution were similar, but the angle distribution, as well as trench density were different. From this result we conclude that the trench alignment and density are the main differences in morphology between the two fiber types, which might explain their different water absoprbtion. Supported by Kelheim Fibres and the Christian Doppler Research Society, Vienna, Austria.

169 POS-52, OGD, Wed, 17:45 Growth and structure of WOx nanolayers on bare Cu(110) and Cu(110)(2×1)O surfaces David Kuhness1, Martin Denk1, Margareta Wagner1, Svetlozar Surnev1, Giovanni Barcaro2, Luca Sementa2, Fabio Negreiros2, Alessandro Fortunelli2, Falko Netzer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, 56124 Pisa, Italy

Tungsten trioxide (WO3) is deposited through direct thermal evaporation of WO3 powder under ultra high vacuum (UHV) conditions onto a bare Cu(110) and onto a Cu(110)(2×1) oxide reconstructed crystal surfaces at room temperature. The growth characteristics have been documented with scanning tunnelling microscopy (STM), low energy electron diﬀraction (LEED) and synchrotron x-ray photoemission (XPS) systematically through the range of low, i.e. 0.1 monolayer (ML) to high (2.0 ML) coverage of WOx and annealing of the sample to temperatures from room temperature to 700◦C. Several phases of WOx structures have been observed and analyzed. Under ◦ particular growth conditions, i.e. 0.6 ML WO3 and a sample temperature of 300 C a well ordered single phase surface with a quasi-square structure could be prepared onto the Cu(110)(2×1)O surface. As the unit cell dimensions of this phase are similar to those of the (ac) projected surface of CuWO4 single crystals a model with a CuWO4 stoichiometry has been proposed and analyzed in DFT calculations. This work has been supported by the ERC Advanced Grant SEPON. CPU time at the CINECA supercomputing center via the ISCRA UT-Ox project is gratefully acknowledged.

POS-53, OGD, Wed, 17:45 Adsorption of Xylan onto Bleached Softwood Fibers Albrecht Miletzky1, Petra Wollboldt2, Manuel Punz3, Hansj¨orgWeber4

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Kompetenzzentrum Holz GmbH, Altenberger Strasse 69, 4040 Linz, Austria 3Zellstoﬀ Forschung, Analytik, Lenzing AG, Werkstrasse 2, 4860 Lenzing, Austria 4Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria

Besides cellulose, hemicelluloses or polyoses (e.g. xylan) are the most common polymers in higher plants and wood. Hardwood contains up to 35% of xylan. Due to chemical pulping – to remove lignin from the wood matrix and to provide fibers for the production of paper – polysac- charides are getting dissolved and degraded in the cooking liquor. This leads in a reduction of the physical strength properties of the paper. The aim of this work is to redeposit different xylans on the surface of pulp fibers to improve their mechanical properties. At first, influencing variables such as pH, temperature, ionic strength, pulp consistency, concentration of xylan in the suspension and the dwell period during adsorption were investigated. After different trials the pulp was hydrolyzed to its sugar monomers and analyzed with high-pressure liquid chromatography (HPLC) and nuclear magnetic resonance spectroscopy (1H NMR). The amount of xylan could be enhanced up to 7% points on bleached softwood kraft pulp. The molecular weight of the xylan and the temperature showed the most effect of adsorption. The determination of the zeta potential of the fibers and the different xylans will be shown too. The effect of the surface and total charge of the substrate is of interest to get more information about the attractive and repulsive forces as well as the mechanisms between the fibers and the colloidal dispersed xylan molecules during adsorption. The electrical properties of the fibers will be analyzed by using kelvin probe force microscopy (KPFM) as well.

170 POS-54, OGD, Wed, 17:45 The contact charging of insulators by atomic force microscopy Monika Mirkowska1, Markus Kratzer1, Christian Teichert1, Helmut Flachberger1

1Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Detailed knowledge on the contact charging behaviour of dielectric materials is of great interest for technological applications like tribocharging separation of mineral additives. As a model system, we investigated the contact charging between quartz or calcite and high-density polyethylene (HDPE). An attempt was made to measure the electric charging of microsize single particles upon contact with well-deﬁned surfaces (monocrystallie surfaces of the same materials as well as with HDPE surfaces). For this purpose, the particles were glued to the ending of AFM cantilevers and force distance (F-d) curves were measured under controlled temperature and humidity conditions. Additional, Kelvin Probe Force Microscopy (KPFM) and Electrostatic Force Microscopy (EFM) measurements were carried out in order to map local electrical changes at the surface.

POS-55, OGD, Wed, 17:45 Anisotropic growth of ultrathin Mn-oxide nanostructures on Ag(100) Thomas Oberm¨uller1, Svetlozar Surnev1, Alessandro Fortunelli2, Wolfram Steurer1, Falko Netzer1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, 56124 Pisa, Italy

Low-dimensional nanostructures of transition metal oxides on well-defined metal surfaces have novel physical and chemical properties which differ drastically from their bulk counterparts. Due to their novel properties, these nanostructures have opened up a new field of fundamental research and they are also of particular interest for a wide variety of potential application in nanotech- nologies, such as in heterogeneous catalysis, electronic devices and corrosion protection. Here we report the formation of uniaxially ordered Mn-oxide nanostripes with almost macroscopic dimensions (> 1000nm) in length on a Ag(100) substrate. The growth of ultra-thin films of manganese oxide on a Ag(100) single crystal surface has been studied using STM, AFM and LEED techniques. Submonolayer coverages of Mn-oxide have been deposited by thermal evaporation under either UHV conditions or in oxygen atmosphere followed by a post-oxidation step. As a function of the chemical potential of oxygen in the post-oxidation step, three different Mn-oxide phases have been detected. While oxygen pressures above 1 × 10−6 mbar lead to a randomly distribution of hexagonally ordered MnOX islands with a triangular shape, a highly anisotropic growth of long and narrow (2×1) stripes forming a network of Mn-oxide islands is observed at oxygen pressures around 5 × 10−7 mbar. For lower oxygen pressures, (2×2) multilayered rectangular islands are found. The physical origin of this anisotropic growth is discussed in a growth model based on the atomic structure of the (2×1) oxide phase. Work supported by the ERC Advanced Grant SEPON

171 POS-56, OGD, Wed, 17:45 Surface Chemistry Chamber for analysis of Oxides Jiˇr´ıPavelec1, Michael Schmid1, Ulrike Diebold1, Gareth Parkinson1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Wien, Austria

A new UHV chamber for the investigation of oxide surface chemistry (e.g. In2O3, SnO2, Fe3O4, perovskites, TiO2, ZrO2) is described. The combination of a specially designed sample mount design and a molecular beam dosing setup solves difficulties associated with performing Tempera- ture Programmed Desorption experiments on bulk oxide samples. Further spectroscopic techniques available on the system include Ultra Violet Photoelectron Spectroscopy, X-ray Photoelectron Spec- troscopy using a monochromatic X-ray source, Low Energy Electron Diffraction, and Ion Scattering Spectroscopy. Utilization of a liquid helium flow cryostat allows us to follow reactions from 20-1200 K, but also allows physisorption of inert gasses such as Kr, a useful probe of surface defects, and also the basis of the Buffer Layer Assisted Growth (BLAG) technique for the in-situ preparation of monodisperse nanoparticles. An Electro spray Deposition System is used for the deposition of non-volatile organic molecules that otherwise cannot be studied in UHV. This surface chemistry instrument provide an ideal compliment to our existing STM based studies.

POS-57, OGD, Wed, 17:45 Microscopical electrical investigations of grain boundaries in ZnO varistor ceramics Andreas Pavitschitz1, Michael Hofstaetter1, Peter Supancic1, Christian Teichert1

1Montanuniversit¨atLeoben, Franz-Josef Strasse 18, 8700 Leoben, Austria

Varistors are nonlinear voltage dependent ceramic resistors used to suppress and limit transient voltage surges. The most common material for varistors is doped polycristalline ZnO which shows highly non-linear current-voltage characteristics with rapidly decreasing resistance above a specific voltage. This effect is caused by so called Schottky barriers at the grain boundaries. Therefore, investigation of the electrical properties of the individual grain boundaries is essential for the understanding of the varistor effect and the improvement of varistor materials. In this study, the electrical properties of ZnO multilayer varistors (MLV) were investigated on the microscopic scale employing conductive atomic-force microscopy (C-AFM), Kelvin probe force microscopy (KPFM), and KPFM with biased MLV electrodes (biased KPFM). The electrical properties of individual grain boundaries were directly measured with a micro-four-point probe measurement setup. Additionally, the crystallographic orientation of the single grains was determined with electron backscatter diffraction (EBSD). The electronic properties were associated with the crystallographic orientation data obtained from EBSD. Employing KPFM on a MLV with an applied bias between the electrodes reveals a step-like voltage drop with steps at the grain boundaries. The relative height of these steps is not uniform. Also a dependence of the relative step-height on the direction of the applied bias was observed.

172 POS-58, OGD, Wed, 17:45 Structure Solution of Surface Induced Crystal Structures: Selected Examples of Calamitic Conjugated Molecules Alexander Pichler1, Markus Neuschitzer1, Michael Dohr1, Alfred Neuhold1, Armin Moser1, G¨unter Schwabegger2, Helmut Sitter2, Clemens Simbrunner2, Theo Dingemans3, Eric G lowacki2, Mihai Irimia-Vladu2, Johannes Gierschner4, Yves Geerts5, Michele Sferrazza5, Roland Resel1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria 3Faculty of Aerospace Engineering, Kluyverweg 1, 2629 HS Delft, Netherlands 4Madrid Institute for Advanced Studies, C/ Faraday 9, Ciudad Universitaria de Cantoblanco, 28049, Madrid, Spain 5Universit´eLibre de Bruxelles, Campus de la Plaine, 1050 Bruxelles, Belgium

Organic molecules in thin films show often specific crystal structures which are different from the known single crystal structures. Such surface-induced crystal structures are formed due to the presence of a surface during the crystallisation process. Within this work we present a specific approach to solve surface induced crystal structures. The solution is based in a first step on the determination of the crystallographic lattice by indexing the observed Bragg peaks of grazing incidence x-ray diffraction measurements. In a second step the molecular packing within the crystallographic unit cell is determined by a rigid body refinement of the molecular structure against the experimentally obtained intensities of the Bragg peaks. To check the reliability of the approach the already known crystal structure of dioctylbenzothieno-benzothiophene (C8-BTBT) will be investigated. As a result of the work the surface induced crystal structures of three different conjugated molecules will be presented: the well-known dye Tyrian Purple (TP) crystallised on a polyethylene surface, the molecule ternaphthalene (NNN) grown on thermally oxidised silicon wafers and phenylene-butoxyphenyl-acrylonitrile (DBDCS) grown on glass surfaces.

POS-59, OGD, Wed, 17:45 Inﬂuence of potassium on the nucleation and growth of para-hexaphenyl on mica Bernhard Putsche1, Adolf Winkler1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Semiconducting oligomers, such as para-hexaphenyl (6P), are attractive candidates as active layer material for organic electronic devices. A model system to investigate the growth parameters is 6P on mica. Adsorbed on freshly cleaved mica, 6P forms needlelike islands of flat lying molecules on top of a wetting layer. Previous investigations have shown that surface modifications, like sputtering, lead to the formation of islands of standing molecules and dewetting. When mica is cleaved, the sample always splits along its potassium layer and a half monolayer of potassium remains on each face. This contribution describes the effects of an increased amount of potassium on the thin film layer growth of 6P. Performing the measurements in ultra-high vacuum ensured precisely controlled conditions for the experiments. 6P was evaporated by using a Knudsen cell and the amount of evaporated material was determined by a quartz microbalance. Potassium was deposited by using a SAES Getter source. Thermal desorption spectroscopy (TDS, in-situ) and atomic force microscopy (AFM, ex-situ) were the main analytical methods to describe the effects of potassium on the growth of the 6P molecules. Auger electron spectroscopy (AES) was applied for chemical analysis of the mica sample before and after the potassium deposition. It turned out that pre-adsorbed potassium causes dewetting and the formation of islands of standing 6P molecules. AES and TDS measurements revealed that proper potassium adsorption/desorption cycles are leading to a saturated potassium coverage of one monolayer on mica, which is stable up to 1000K.

173 POS-60, OGD, Wed, 17:45 Thin cellulose ﬁlms as model systems for paper-ﬁbres Sebastian Rohm1, Robert Schennach1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Paper fibres mainly consists of long cellulose and hemicellulose molecules. To investigate how these molecules are attracted to each other thin cellulose-layers are spin-coated on a 2x2cm2 silicon- wafer. Since Cellulose is difficult to solve into a solvent, first Trimetylsilycellulose (solved into Toluol) is spin-coated on the surface which then is transformed to cellulose by hydrolysis. This spin-coating process is done 4 times to get a layer-thickness of about 200nm. For swelling these wafers are laid into distilled water. To measure ionic influences some wafers are also swelled into water with 0.1mol/l CaCl2. After that two cellulose-surfaces are laid against one another and put into a dryer. There the physical bonds between these surfaces are formed while the water evaporates. After 4 hours of drying the thin films are joint and z-strength-tests can be performed. For that, the wafers are fixed on the silicon-side and a tensile-test is made. The maximum force, the strain and the energy needed is measured in this experiment. The advantage of this method is, that only physical bonds like van der Waals-, Ionic- and Hydrogenbonds are contributing. In addition, the films are investigated with an Atomic-Force-Microscope, before and after the strength- tests, to find out where the molecules form bonds with each other. To measure the influence of hemicellulose-molecules, xylan-layers are spin-coated on the cellulose-layer and the same measurements are performed.

POS-61, OGD, Wed, 17:45 Initial growth of Rubicene on Silicon Oxide Boris Scherwitzl1, Adolf Winkler1, Walter Lukesch1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

In the course of the last decades organic microelectronic devices became of increasing importance. The use of organic or hybrid organic devices yields advantages in a variety of fields of application. Flexible displays or solar cells are already notable examples of present day technology. Inventing new and improving existing devices requires full understanding and best control of building processes. Therefore studies of the initial stages of organic thin film growth are essential. This contribution describes the behavior of rubicene film growth on silicon oxide with respect to sample treatments. Physical vapor deposition was the method of choice for creating films from sub-monolayers up to multilayers. Rubicene was evaporated by using a Knudsen cell and the amount of evaporated material was determined by a quartz micro balance. Auger Elec- tron Spectroscopy (AES) was applied for chemical analysis and proved homogeneity of the sample. Thermal Desorption Spectroscopy (TDS) was the main analytical method along with Atomic Force Microscopy (AFM) to determine the behavior of the molecules on the substrate. The surface was intentionally altered by argon sputtering and carbon deposition. Performing the measurements in ultra-high vacuum (UHV) ensured precisely controlled conditions for the experiments, although the AFM measurements were subsequently done ex-situ. It could be shown that the rubicene formation, especially the thermal stability and dewetting, depends strongly on the substrate conditions. Furthermore, it could be demonstrated by AES and TDS that on a clean silica substrate the first monolayer of rubicene dissociates upon heating the surface.

174 POS-62, OGD, Wed, 17:45 Bismuth surface phonon modes from helium atom scattering experiments Anton Tamt¨ogl1, Michael Mayrhofer-Reinhartshuber1, Patrick Kraus1, Davide Campi2, Giorgio Benedek2, Wolfgang Ernst1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2Universit´adegli Studi di Milano-Bicocca, Via Roberto Cozzi 53, 20125 Milano, Italy

The semimetal bismuth (Bi) is a prime candidate for the study of quantum size effects in solids[1]. Only recently anisotropies in conductivity measurements of Bi have been observed[2]. Whereas Bi bulk properties have been analyzed very well open questions concerning the lattice dynamics of the Bi surfaces remain[1]. Helium Atom Scattering (HAS) allows the investigation of elastic as well as inelastic phenomena associated with the shape and changes of the electron density corrugation at the Bi(111) surface[3]. Therefore, using inelastic HAS measurements the surface phonon dispersion of Bi(111) could be determined for the first time. In both high-symmetry directions the phonon dispersion exhibits a Rayleigh mode, a strong longitudinal resonance and a nearly dispersionless branch at approximately 4 meV. A comparison of the phonon dispersion with calculations from density functional perturbation theory show that the longitudinal resonance exhibits the largest amplitude in the second layer and the flat phonon branch originates even from an atomic displacement in the third layer. The observation of this subsurface modes in helium scattering is only possible due to the electron phonon-coupling. Thereby oscillations of the electron charge density above the first layer are caused by the movement of the atoms in subsurface layers. [1] P. Hofmann, Prog. Surf. Sci. 81 (2006) 191. [2] S. A. Parameswaran et al., Nat. Phys. 8 (2012) 7 [3] M. Mayrhofer-Reinhartshuber et al., J. Phys.: Cond. Matt. 24 (2012) 104008

POS-63, OGD, Wed, 17:45 Attachment limited versus diffusion limited nucleation of organic molecules: Hexaphenyl on sputter-modified mica Levent Tümbek1, Adolf Winkler1

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

The nucleation and growth of point-like particles, like metal atoms, is usually discussed in the framework of diffusion limited aggregation (DLA). In this contribution we demonstrate that for extended particles, like for the rod-like organic molecules hexaphenyl (6P), this nucleation scenario does not always hold. The reason is that the condition of an incorporation probability of unity is not fulfilled any longer for these monomers. A special characteristics of DLA is that the island density N scales with N = c(R/D)(i/(i+2)), with R: deposition rate, D: diffusion rate, and i: critical island size. For this scenario the critical island size i, which can be easily obtained from the slope in the plot lnN vs lnR, should vary between 0.33 and 1. However, for the island growth of 6P on especially sputter-amorphized mica we obtain a slope of 1.4. Indeed, this result can be explained by assuming that the nucleation is governed by attachment limited aggregation (ALA). In this case the island density N scales with N = c(R/D)(2i/(i+3)), and i can vary between 0.5 and 2. Consequently, a critical island size of 7 is obtained in this case. The crucial parameter for the growth mode is the roughness of the substrate surface, as induced by ion sputtering. With increasing surface roughness the diffusion probability of the molecules decreases and the growth mode changes from ALA to DLA.

175 POS-64, OGD, Wed, 17:45 Displacement and Replacement in Organic Heterostructures Thomas Ules1, Eva Reinisch1, Markus Ostler2, Michael Ramsey1, Georg Koller1

1University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 2University Erlangen N¨urnberg, Erwin-Rommel-Strasse 1, 91058 Erlangen, Germany

In this LEED/Angle Resolved UPS study an heterostructure system is presented which shows a counter intuitive reversible replacement of two different organic molecules at the molecule substrate interface. The organic rod like molecule sexiphenyl (6P) forms a well ordered monolayer on Ag(110) which is clearly characterised by its valence band emissions and its geometric structure. Valence band tomography of the π orbitals show no evidence of backdonation to the 6P LUMO and that 6P is in its twisted confirmation with its long molecular axes aligned perpendicular to the substrate atomic rows. Upon the deposition of pentacene (5A) on it, a density of states appears at the Fermi edge. Fermi surface maps identify this intensity as the ex-LUMO of 5A filled via backdonation from the substrate. This, together with the fact that 6P emissions are still dominant, suggests that 5A has gone to the interface. Extraordinarily, on ramping the temperature the 6P features first disappear and then reappear at the temperature of desorption of the 5A/Ag(110) monolayer. This de/re-wetting is also observed with LEED where de-wetting of 6P results in the appearance of a well ordered 5A monolayer LEED pattern which, at the 5A desorption temperature, changes completely to the 6P monolayer pattern. That the chemisorbed 5A desorbs before the physisorbed 6P is apparently counterintuitive and will be discussed in terms of the energetics of de-wetting (3D island formation) and wetting monolayers. Acknowledement: This work is supported by the Austrian Science Foundation FWF.

POS-65, OGD, Wed, 17:45 Reversible transitions between surface reconstructions on SrTiO3 Zhiming Wang1, Stefan Gerhold1, Michael Schmid1, Ulrike Diebold1

1Vienna University of Technology, Wiedner Hauptstrasse 8-10/134, 1040 Wien, Austria

SrTiO3 as an archetypical perovskite oxide has attracted intense interest in diverse fields ranging from fundamental solid-state physics to photocatalysis chemistry, material science, as well as electronics applications. Related research has become even more exciting since the recent discovery of a 2DEG at the SrTiO3 surface and interfaces. In all these applications the structural and electronic surface properties are of vital importance, yet perovskite surfaces are notoriously complex and hard to control. Here we report investigations on SrTiO3 surfaces using STM, LEED and + XPS. Atomically well-defined SrTiO3 (110) surfaces can be obtained by Ar sputtering followed by annealing. Mono-phased reconstructions are obtained, and the evolution between different phases can be tuned reversibly by depositing Sr or Ti. The tuning mechanisms are revealed as a chemical concentration-driven process on the surface.

176 POS-66, OGD, Wed, 17:45 Investigation of the surface charge of Viscose Fibres by XPS and ATR Frederik Weber1, Robert Schennach1, Rene Eckhart1, Georg Koller2, Ingo Bernt3

1Graz University of Technology, Petersgasse 16, 8010 Graz, Austria 2University of Graz, Universit¨atsplatz5, 8010 Graz, Austria 3Kelheim Fibres GmbH, Regensburger Strasse 109, 93309 Kelheim, Germany

The primary objective within the CD-Laboratory is to get a better understanding of the mechanism how paper fibres stick together. There are five types of interactions that determine the specific joint strength in the contact zone between the fibres: mechanical interlocking, interdifu- sion, induced dipoles, van der waals forces and hydrogen bonds. Regenerated cellulose fibres like viscose fibres are in principle chemically identical to wood pulp fibers. They are available with well defined parameters like cross section, fibre length or fibre width and in contrast to wood pulp fibres, are rather smooth, without fibrils on the surface. Therefore, they are model-fibres which are perfect for investigating the mechanism of fibre-fibre bonds and to get a better understanding how paper fibres stick together and perform in a paper sheet. A big advantage of viscose fibres is the feasibility to mix several additives to them. Thereby defined anionic as well as cationic fibres can be achieved. Without mechanical interlocking, viscose fibres can be used to investigate the influence of surface charges on the bond strength. Four kinds of fibres were investigated by X-ray photoelectronspectroscopy (XPS) and attenuated total reflection spectroscopy (ATR). The investigated fibres only differ in charge but have the same cross section and dimensions. Two anionic and a cationic fibre were investigated using the regular viscose fibre as a reference. Via XPS and ATR the amount of anionic and of the cationic additives were investigate to get an idea of the charge density of all used fibres.

POS-67, OGD, Wed, 17:45 Selective Photo-induced Cross-linking of Polynorbornens: Towards the Fabrication of Polymer 2D- and 3D- Microstructures Archim Wolfberger1, Thomas Griesser1, Ute Daschiel1,2, Volker Schmidt3, Abdellatif Jerrar4, Christian Teichert4, Wolfgang Kern1

1University of Leoben, Otto-Gl¨ockel-Strasse 2, 8700 Leoben, Austria 2Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben, Austria 3Joanneum Research GmbH Weiz, Franz-Pichler-Strasse 30, 8160 Weiz, Austria 4Montanuniversit¨atLeoben, Franz Josef Strasse 18, 8700 Leoben, Austria

Ring opening metathesis polymerization (ROMP) has become an important tool for the synthesis of highly defined polymers and various polymer architectures. In the present work, the residual double bonds in ROMP derived polymeric materials were exploited for a photoinduced thiol-ene reaction in order to achieve a selective cross-linking of the macromolecules. To demonstrate the versatility of this reaction for the realization of polymeric microstructures, thin films of poly(norbornene dicarboxylic acid, dimethylester) were structured by means of photolithography. Besides the photoinduced thiol-ene reaction, which was investigated by means of FTIR measurements, also the cross-linking of the macromolecules and thus the change in the solubility were assessed by means of sol-gel analysis. Thin films of this polymer were laterally patterned using conventional single photon lithography leading to resolutions in the µm range. Going a step further, this approach can also be used for realizing 3D polynorborne microstructures employing the two photo absorption writing technique. The obtained 3D features have been visualized by scanning electron microscopy and atomic force microscopy, respectively. The accessibility and reactivity of the polynorbornene main chain C = C double bonds in the thiol-ene reaction paves the way towards novel strategies for the realization of polymer 2D and 3D microstructures.

177 POS-68, PMP, Wed, 17:45 Raman investigation of tannin foams Maurizio Musso1, Alexander Petutschnigg2, Gianluca Tondi2

1University of Salzburg, Hellbrunnerstrasse 34, 5020 Salzburg, Austria 2FHS, University of Applied Sciences, Urstein S¨ud1, 5412 Puch/Salzburg, Austria

Tannin-based organic foams are new foam materials which are environmentally friendly, resis- tant to fire and inexpensive, and intended to be used for building insulation, and also as water absorber or shock absorber. These foams can be produced via an acid catalyzed polycondensation reaction between condensed flavonoids and furfuryl alcohol [1-2]. Several studies deal with the mechanism involved in this process [3], but some ambiguities still persist. Raman spectroscopy is an analytical technique suitable for the non-destructive chemical investigation of polymers, allowing to determine the presence of functional groups within a polymer through the interaction of laser light with the vibrational modes of the molecules setting up the sample under investigation [4]. By this spectroscopic technique we have characterized the tannin-based foams and compared their spectral signature with that of tannins, and of polymerized furfuryl alcohol [5]. Similarities and differences to the spectral features of carbonaceous material are discussed. [1] Tondi G., Zhao W., Pizzi A., Du G., Fierro V., Celzard A., Bioresources Technology 100, 5162 (2009) [2] Tondi G., Fierro V., Pizzi A., Celzard A., Carbon 47, 1480 (2009) [3] Gandini A., Polym. Chem. 1, 245 (2010) [4] M.A. Amer, Raman Spectroscopy for Soft Matter Applications, Wiley, Hoboken (2009) [5] S. Bertarione, F. Bonino, F. Cesano, S. Jain, M. Zanetti, D. Scarano, and A. Zecchina, J. Phys. Chem. B 113, 10571 (2009)

POS-69, PMP, Wed, 17:45 The eﬀect of sacriﬁcial bonds on the mechanical behavior of a single polymer chain- A Monte Carlo study Soran Nabavi1, Markus Hartmann1

1Montanuniversit¨atLeoben, Franz Josef Strasse 18, 8700 Leoben, Austria

Understanding the basic building principles of biological materials from a fundamental point of view is a necessary prerequisite for possible transfer of these principles to technology. The byssal thread is an especially fascinating material showing high toughness, stiffness and extensibility. The byssal thread is secreted by marine mussels to adhere to rocky substrates. Being covered with a hard coating providing wear resistance, it shows an extensibility of more than 100 % with the ability of self-healing. Experimental studies on this system suggest that the high extensibility is due to so called “sacrificial bonds” (SBs). Sacrificial Bonds are weaker than the covalent bonds holding the structure together and they can thermally induced open and close reversibly. The SBs break before the covalent bond rupture, providing hidden length and allowing for efficient energy dissipation. By this effect the toughness of the structure is significantly enhanced. These findings motivate the following simple model. The basic unit is a linear, covalently bonded polymer chain. Some of the monomers (so called sticky sites) can additionally form sacificial bonds. Starting from a collapsed chain cyclic loading experiments were mimicked by determination of load-displacement curves by calculation of the mean force exerted by the chain for several end-to-end distances. The effect of the density and of the arrangement (ordered, random) of sticky sites on the mechanical behavior of the chain was investigated. For sufficiently high sticky site densities a pronounced hysteresis between stretching and relaxing of the chain could be observed.

178 Contributors

A Blaha, Peter, 157 Abele, Hartmut, 148–150, 152 Blatnik, Matthias, 49 Abermann, Stephan, 121 Brandner, Hannes, 96 Adam, Wolfgang, 21, 43 Brandstätter,Birgit, 144 Ahn, Sang Il, 93 Briegel, Hans, 21 Aichmayer, Barbara, 157 Brueckl, Hubert, 121 Akbarzadeh, Johanna, 121, 154 Brunner, Frank, 95 Akhtar, Nadeem, 144 Brunner, Roland, 86, 93 Akis, Richard, 86 Brunner, Stefan, 59, 148 Alberti, Carlos Armando, 165 Buchriegler, Josef, 42, 51, 153 Alexewicz, Alexander, 95 Bücker, Robert, 76 Alkofer, Reinhard, 46, 48, 49 Bucko, Tomas, 120 Al-Saidi, Wissam, 120 Bulla, Lukas, 94 Amann, Peter, 118 Burgstaller, Lukas, 93 Amenitsch, Heinz, 87, 97, 99 Burke, Adam, 86 An der Lan, Lukas, 146 Andersson, Pontus, 151 C Andrews, Aaron Maxwell, 92, 95, 160 Cacho-Nerin, Fernando, 87, 97, 99 Anjum, Naveed, 144 Campi, Davide, 175 Aoki, Nobuyuki, 86 Capriotti, Mattia, 95 Argentero, Giacomo, 127 Cargnelli, Michael, 40 Arndt, Markus, 76 Carilli, Jessica, 112 Arrigoni, Enrico, 91 Cervinka, Thomas, 152 ASACUSA Collaboration, The, 40 Charles, William, 93 Atkinson, Paola, 86 Chioncel, Liviu, 91 Ausserlechner, Simon, 96 Choi, Joongil Jake, 126 Aziz, Kirmanj, 161 Chrastina, Daniel, 154 Colavita, Paula, 121 B Cordin, Michael, 118 Badurek, Gerald, 52 Costacurta, Stefano, 87 Balakireva, Irina, 151 Cronenberg, Gunther, 148 Balazs, Peter, 67, 68 Cronin, James, 17 Baranov, Mikhail, 118 Curceanu, Catalina, 59 Barcaro, Giovanni, 124, 170 Bartl, Peter, 146 D Bauer, Günther, 155 Daghofer, Maria, 100, 101 Baumgartner, Dietmar, 167 Daschiel, Ute, 177 Baumgartner, Oskar, 92 Daxner, Mathias, 146 Baumgartner, Robert, 69 Della Valle, Raphaele, 125 Belushkin, Maxim, 95 Denifl, Stephan, 79, 81, 146 Benedek, Giorgio, 175 Denk, Mariella, 168 Bergauer, Thomas, 56, 57 Denk, Martin, 124, 170 Berger, Karl, 167 Denk, Richard, 168 Berger, Thomas, 111, 166 Detz, Hermann, 92, 160 Bergmann, Olaf, 42 Diaz, Ana, 154 Berkebile, Stephen, 129, 130 Diebold, Ulrike, 118, 126, 127, 172, 176 Bernet, Stefan, 19 Diehl, Sebastian, 118 Bernt, Ingo, 177 Diermaier, Martin, 40, 41 Berrada, Tarik, 76 Dimopoulos, Theodorus, 121 Bertel, Erminald, 118 Dingemans, Theo, 173 Besser, Bruno, 106 Ditlbacher, Harald, 77 Betz, Thomas, 75 Djuric, Tatjana, 130 Bilski, Pawe l,166 Doblhoff-Dier, Nicolette, 20 179 Dohr, Michael, 96, 173 Fuchsbichler, Bernd, 98 Doljeschi, Paul, 56, 57 Draxl, Claudia, 119 G Duehrssen-Debling, Michael, 54 Gajic, Rados, 169 Gall, Johannes, 129 E Gammer, Christoph, 97 Echt, Olof, 146 Gamper, Bettina, 82 Eck, Hans, 163 Gansch, Roman, 92 Eckhart, Rene, 177 Ganser, Christian, 167, 169 Egger, David, 120 Garay Walls, Francisca, 54 Eichmann, Gernot, 50 Geerts, Yves, 96, 125, 173 Einkemmer, Lukas, 160 Geist, David, 97 Ellis, Andrew, 146 Gerhold, Stefan, 176 Ellmeier, Michaela, 145 Gerstmann, Johann, 30 Erhart, Jacqueline, 149, 150, 152 Gfall, Immanuel, 56, 57 Ernst, Wolfgang, 75, 78, 80, 81, 123, 175 Gießibl, Franz, 18 Ertler, Christian, 90, 91 Gierschner, Johannes, 173 Eschlböck-Fuchs, Simon, 145 Giordani, Silvia, 121 Etzelstorfer, Tanja, 88, 154, 155 Glattauer, Robin, 58 Gleichweit, Christoph, 130, 168 F Glushko, Oleksandr, 93 Faccinelli, Martin, 156 Gmachl, Claire, 93 Falcaro, Paolo, 87 Göcke, Tobias, 46 Fattinger, Michael, 131 Golob, Andreas, 105 Faustini, Marco, 87 Golser, Robin, 41, 42, 51, 151, 153 Fecht, Hans-Jörg,98 Gösselsberger, Christoph, 52 Federmann, Silke, 40 Gottfried, Strasser, 93 Feige, Jenny, 41, 42 Goulart, Marcelo, 79, 146 Ferry, David, 86 G lowacki, Eric, 173 Fifield, Keith, 41 Graber, Gerhard, 71 Fillunger, Harald, 149 Granitzer, Petra, 155 Filter, Hanno, 148 Griesser, Thomas, 177 Fischer, Christian, 46 Grimm, Matthias, 95 Fischer, Franz, 100 Grobosch, Mandy, 124 Fischer, Julia, 54 Grogger, Werner, 123 Fisslthaler, Evelin, 123 Groiss, Heiko, 155 Flachberger, Helmut, 171 Grosso, David, 87 Flaig, Sylvia, 154 Gruber, Christian, 77 Fobes, David, 118 Gruber, Lukas, 59, 148 Foffi, Giuseppe, 95 Gruber, Thomas, 75 Folk, Reinhard, 106 Gschliesser, David, 79, 146 Forchel, Alfred, 160 Guedes Matias, Carolina, 146 Forró,László,95 Gusenleitner, Sina, 130 Forstner, Oliver, 51, 151 Gutberlet, Thomas, 113 Fortunelli, Alessandro, 124, 170, 171 Franchini, Cesare, 118 H Frank, Matthias, 65, 66 Hadley, Peter, 156 Frank, Sebastian, 58 Haiden, Philip, 149 Frankenberger, Annekathrin, 56, 57 Hajek, Michael, 111, 165, 166 Franosch, Thomas, 95 HAK/HAS, Mistelbach, 31 Friedl, Markus, 56, 57 Hammer, René,91 Frisén,Jonas, 42 Hanstorp, Dag, 151 Fritz-Popovski, Gerhard, 87, 157 Harrington Jr, Robert Duane, 54 Fromherz, Thomas, 93 Hartmann, Markus, 100, 178 Frühwirth, Edwin, 55 Hasewend, Matthias, 80 Frühwirth, Rudolf, 57, 58 Haslinger, Michael, 145 180 Hauser, Andreas, 75, 81 Kalchmair, Stefan, 92 Hebenstreit, Florian, 46 Kalliokoski, M., 162 Heiss, Wolfgang, 87, 88 Kaltenbrunner, Martin, 90 Heitz, Johannes, 145 Kamencek, Thomas, 61 Herbst, Tina K., 47 Karnthaler, Peter, 97 Hieckel, Marcel, 118 Kaseß, Christian, 70 Hinterreiter, Andreas, 145 Kautsch, Andreas, 80 Hirschl, Robin, 29 Kazakov, Georgy, 147 Hirschmugl-Gaisch, Sabine, 163 Keplinger, Mario, 88 Hirtl, Albert, 148 Kern, Wolfgang, 177 Hlawacek, Gregor, 123 Kerscher, Tobias, 156 Hofer, Ferdinand, 77 Khinast, Johannes, 111 Höfling,Sven, 160 Kiener, Daniel, 19 Hofstaetter, Michael, 172 Kirchengast, Gottfried, 162 Hofstätter,Christina, 111, 166 Kirchner, Helmut, 158 Hohage, Michael, 129, 168 Kirnstötter,Stefan, 156 Hohenau, Andreas, 77, 80 Klima, Stefan, 169 Hohenester, Ulrich, 77 Klopf, Michael, 150 Hohl, Roland, 111 Kneringer, Emmerich, 45 Höldrich, Robert, 65 Knoll, Peter, 148, 157, 161 Holec, David, 100 Knupfer, Martin, 124 Holy, Vaclav, 88, 155 Koch, Markus, 78, 80, 81, 123 Hopfer, Markus, 49 Koch, Reinhold, 131 Hörselmann,Ingo, 124 Kohlfürst,Christian, 46 Horvath, Miklos, 149 Kol´ıbal,Miroslav, 127 Hrauda, Nina, 155 Koller, Georg, 125, 129, 176, 177 Huber, Harald, 152 Koller, Stefan, 98 Huber, Markus, 47, 48 Kolmhofer, Philipp, 145 Huber, Norbert, 145 Kondratenko, Sergey, 126 Huesing, Nicola, 154 Konrad, Gertrud, 52, 149, 150, 152 Hühnermann,Harry, 144 Körner,Christine, 111 Humer, Markus, 93 Korschinek, Gunther, 41 Kosina, Hans, 92 I Kourtis, Stefanos, 100 Innocenzi, Plinio, 87 Kovac, Pavol, 94 Irimia-Vladu, Mihai, 173 Kovalenko, Maksym, 88 Irmler, Christian, 56, 57 Kozyrev, Yury, 126 Isella, Giovanni, 154 Kraft, Jochen, 134 Isepp, Katharina, 150 Krämer,Sebastian, 146 Ishiwatari, Tomoichi, 40 Kraml, Armand, 107 Kraml, Sabine, 58 J Kranzelbinder, Heinrich, 162 Janits, Beatrix, 164 Krätschmer, Ilse, 44 Jankovec, Martin, 148 Kratzer, Markus, 126, 169, 171 Jaques, Vincent, 154 Kraus, Patrick, 175 Jeney, Sylvia, 95 Krause, Reinhard, 162 Jenke, Tobias, 39, 148 Kreiml, Patrice, 169 Jericha, Erwin, 52 Krenn, Heinz, 94, 108 Jerrar, Abdellatif, 177 Krenn, Joachim, 77, 80 Jesacher, Alexander, 19 Krenn, Kurt, 157 Jestin, Jacques, 113 Kreuzer, Wolfgang, 69–71 Jovanovic, Djordje, 169 Kriegner, Dominik, 88 Jungnikl, Karin, 99 Krois, Günter, 78 Jussel, Patrick, 44 Kronland-Martinet, Richard, 68 Kuetgens, Ulrich, 152 K Kufstein, Stadttheater, 22 Kahn, Saranjam, 19 181 Kuhness, David, 124, 170 Melikhov, Dimitri, 151 Kumar, Sanjeev, 101 Melisek, Tibor, 94 Kusar, Primoz, 77 Mendoza, Benjamin Levy, 165 Kutschera, Walter, 42 Menezes, José,111 Menzel, Alexander, 118 L Merchel, Silke, 41 Laback, Bernhard, 68–70 Mercurio, Giuseppe, 20 Lackner, Florian, 78 Messing, Maria, 88 Laggner, Peter, 99 Meunier, Sabine, 68 Lammegger, Roland, 145 Michlmayer, Leonard, 42 LEANNIS network, The, 39 Mihocic, Michael, 70 Lechner, Rainer, 87 Miletzky, Albrecht, 170 Leidl, Roman, 167 Milko, Matus, 119 Leidlmair, Christian, 146 Mirkowska, Monika, 171 Leising, Günther, 30 Mitaroff, Winfried, 58 Leitner, Martin, 156, 162 Mittendorfer, Florian, 118, 128 Leitner, Matthias, 159 Mitter, Mario, 48, 49 Lettenbichler, Jakob, 57 Mittermair, Robert, 168 Li, Chenghao, 160 Mor, Flavio, 95 Liebl, Jakob, 42 Morak, Roland Johann, 157 Lindahl, Anton, 151 Morales, Puerto, 155 Löffler,Andreas, 160 Moser, Armin, 125, 173 Lonez, Caroline, 113 Moser, Martin, 152 Lorbek, Stefan, 96 Muccioli, Luca, 162 Lucha, Wolfgang, 151 Mülleder,Thomas, 61 Luckabauer, Martin, 98 Müllegger,Stefan, 131 Lüftner,Daniel, 125 Müller,Mario, 61 Lukas, Wolfgang, 45 Müller,Stefan, 156 Lukesch, Walter, 174 Murer, Gerhard, 135 Lutzer, Bernhard, 54 Musso, Maurizio, 157, 161, 178

M N Maaß, Sebastian, 152 Nabavi, Soran, 178 Maas, Axel, 47 Nadler, Moritz, 57 Mader, Valentin, 48 Necciari, Thibaud, 68 Magnes, Werner, 145 Negreiros, Fabio, 124, 170 Mahmoudi, Nazila, 58 Netzer, Falko, 124, 130, 170, 171 Mai, Patrick, 160 Neuhold, Alfred, 96, 173 Mair, Klaus, 42, 51 Neuschitzer, Markus, 96, 173 Majdak, Piotr, 69, 70 Niedermayr, Michael, 147 Malbrunot, Chloé,40 Nikbakhti, Maryam, 167 Malfatti, Luca, 87 Novotny, Zbynek, 127 Mandl, Bernhard, 88 Mao, Zhiqiang, 118 O Marmiroli, Benedetta, 87, 97, 99 Oberauer, Christoph, 161 Marton, Johann, 39, 40, 59, 148 Obermüller,Thomas, 171 Martschini, Martin, 42, 51, 151 Ochiai, Yuichi, 86 Massiczek, Oswald, 40, 41 Ostermann, Laurin, 78 Matias, Carolina, 79 Ostler, Markus, 129, 176 Matkovic, Aleksandar, 169 Oswald, Josef, 158 Matthiä,Daniel, 166 Mauracher, Andreas, 146 P Mayrhofer, Paul, 100 Paasch, Gernot, 124 Mayrhofer-Reinhartshuber, Michael, 175 Pabisch, Silvia, 158, 160 Mazuheli, Stefan, 61 Pabst, Georg, 113 Meisels, Ronald, 86, 93 Pacheco, Manuel, 159 182 Paris, Oskar, 87, 100, 157, 160 Ramsey, Michael, 125, 129, 130, 176 Parkinson, Gareth, 127, 172 Rappolt, Michael, 99 Parlar, Anil, 95 Rashidi, Mohammad, 131 Parth, Dieter, 31 Rastelli, Armando, 86 Parz, Peter, 98, 159 Ratschek, Martin, 80, 81 Pavelec, Jiˇr´ı,172 Rechberger, Veronika, 163 Pavitschitz, Andreas, 169, 172 Redinger, Josef, 118, 128 Pawlowski, Jan Martin, 47 Reichel, Erich, 163 Pedarnig, Johannes, 145 Reingruber, Herbert, 122 Peić,Antun, 121 Reininger, Peter, 92 PERC Collaboration, The, 52 Reinisch, Eva, 129, 176 Perez, Javier, 97 Reissner, Michael, 94, 155 Perova, Tatiana, 121 Reitberger, Klaus, 22 Peterlik, Herwig, 121, 154, 158, 160 Reiter, Wolfgang, 104 Petutschnigg, Alexander, 178 Reitz, Günther, 111, 166 Pichler, Alexander, 173 Rennhofer, Harald, 160 Pichler, Franz, 108 Rennhofer, Marcus, 121, 167 Pillmayr, Norbert, 28, 33 Rentenberger, Christian, 97 Pirró,David, 65 Resel, Roland, 96, 125, 130, 173 Plagg, Stefan, 71 Ritsch, Elmar, 54 Pobitzer, Martin, 71 Ritsch, Helmut, 78, 146 Podloucky, Raimund, 118, 128, 156 Ritsch-Marte, Monika, 19 Poelsema, Bene, 123 Rohlén,Johan, 151 Pogany, Dionyz, 95 Rohm, Sebastian, 174 Pohl, Wilfried, 32 Roider, Clemens, 19 Pollinger, Andreas, 145 Romero Vidal, Antonio, 59 Pölt,Peter, 122, 155 Roscioni, Otello, 162 Portolan, Stefano, 160 Rössler,Roman, 145 Posch, Thomas, 29 Rubezhanska, Maria, 126 Postler, Johannes, 79, 146 Rudamas, Carlos, 159, 165 Potocar, Thomas, 152 Rugel, Georg, 41 Pototschnig, Johann, 81 Ruiz, Victor, 120 Pottlacher, Gernot, 161 Rumpf, Klemens, 155 Pötz,Walter, 89–91 Ruysschaert, Jean-Marie, 113 Prehal, Christian, 126 Priller, Alfred, 42, 51, 153 S Probst, Michael, 146 Sacher, Stefan, 111 Prügger,B., 162 Sachslehner, Franz, 104 Puchalska, Monika, 166 Salzburger, Andreas, 45, 54 Puchegger, Stephan, 158, 160 Salzmann, Ingo, 96, 125 Puff, Werner, 98, 159 Sanchis-Alepuz, Helios, 49 Punz, Manuel, 170 Sandoghdar, Vahid, 24 Puschnig, Peter, 119, 125, 129 Sartori, Barbara, 87, 97, 99 Puschnigg, Benjamin, 81, 146 Sassermann, Mathias, 160 Putsche, Bernhard, 173 Sauerzopf, Clemens, 40 Savel, Sophie, 68 Q Schaefer, Bernd-Jochen, 47, 49 Queteschiner, Daniel, 129, 168 Schaelicke, Andreas, 54 Schaff, Jean-Francois, 76 R Schaffer, Mathias, 33 Radinger, Gregor, 32 Schafler, Erhard, 121 Radulescu, Aurel, 113 Scheibelhofer, Otto, 111 Rahbaran, Babak, 153 Scheier, Paul, 79, 81, 146 Rajagopalan, Shibi, 58 Scheinert, Susanne, 124 Ralevic, Uros, 169 Schennach, Robert, 119, 121, 167, 169, 174, 177 Rammerstorfer, Franz, 100 Scherwitzl, Boris, 174 183 Schiefler, Gustav, 154 Steinhauser, Georg, 147 Schittelkopf, Eduard, 163 Steinmüller-Nethl,Doris, 134 Schlosser, Viktor, 167 Sterba, Johannes, 51 Schmalzer, Nadine, 61 Steurer, Wolfram, 171 Schmid, Michael, 118, 126, 127, 172, 176 Stickler, Benjamin, 91 Schmidt, Edith, 42 Stöger,Bernhard, 118 Schmidt, Franz, 77 Stolterfoht, Martin, 162 Schmidt, Günther, 157 Strasser, Gottfried, 92, 95, 160 Schmidt, Oliver, 86 Stricker, Stefan, 46 Schmidt, Volker, 177 Stuetz, Engelbert, 164 Schmied, Franz, 121 Süess,Martin, 154 Schmiedmayer, Jörg,76 Sun, Lidong, 129, 168 Schmitz, David, 75 Supancic, Peter, 172 Schmon, Alexander, 161 Surnev, Svetlozar, 124, 170, 171 Schneider, Christian, 160 Suzuki, Ken, 59, 148 Schnell, Melanie, 75 Swain, John, 17 Schöbel, Harald, 146 Sytnyk, Mykhailo, 88 Schöfbeck, Robert, 43 Schreitl, Matthias, 147 T Schrenk, Werner, 92, 93 Tamtögl,Anton, 175 Schumm, Thorsten, 76, 147 Tanzer, Katrin, 81 Schustereder, Werner, 156 Teichert, Christian, 96, 126, 167, 169, 171, 172, Schwabegger, Günter, 173 177 Schwanda, Christoph, 45 Teischinger, Florian, 53 Schwarz, Benedikt, 92 Thalhammer, Gregor, 19 Schwarz, Karlheinz, 157 Thórhallsdóttir,Ester, 162 Schwarz, Stefan, 149 Thorne, Felicitas, 45 Schwarzer, Clemens, 93 Tinguley, Jean-Claude, 80 Sclafani, Michele, 76 Tkatchenko, Alexandre, 120 Scordo, Alessandro, 59 Todt, Melanie, 100 Sementa, Luca, 124, 170 Tondi, Gianluca, 178 Sereni, Paolo, 157, 161 Topolovec, Stefan, 94 Seyller, Thomas, 129 Treberer-Treberspurg, Wolfgang, 56 Sferrazza, Michele, 96, 125, 173 Tributsch, Helmut, 28 Shen, Quan, 96 Tritthart, Stefanie Anna, 164 Sherwood, Peter, 54 Trotta, Rinaldo, 86 Shubert, Alvin, 75 Tschürtz,Sabine, 162 Shyjumon, Ibrahimkutty, 99 Tümbek, Levent, 130, 168, 175 SIDDHARTA Collaboration, The, 39 Siddiqui, Imran, 82 U Siegel, Stefan, 160 Ules, Thomas, 125, 129, 176 Siess, Josef, 135 Usanova, Anna, 44, 54 Sigg, Hans-Christian, 154 Sikola,ˇ Tomáˇs,127 V Simbrunner, Clemens, 173 Valentan, Manfred, 56, 57 Sitter, Helmut, 173 Vandenbranden, Michel, 113 Smiljic, Dusko, 56, 57 van den Brink, Jeroen, 100, 101 Sontacchi, Alois, 65 Van Frank, Sandrine, 76 Sorta, Stefan, 94 van Gastel, Raoul, 123 Spalding, Kirsty, 42 Van Opdenbosch, Daniel, 157 Spolenak, Ralph, 154 Vasic, Borislav, 169 Sprengel, Wolfgang, 98, 159 Vazquez Doce, Oton, 59 Stangl, Julian, 88, 154, 155 Veligura, Vasilisa, 123 Stanohevic, Zlatan, 92 Venderbos, Jörn,100, 101 Steier, Peter, 42, 51, 112, 153 Vieider, Manuel, 162 Steinacker, Harold, 50 Vizcaino, Violaine, 81, 146 184 Volgger, Stefan, 161 Zojer, Egbert, 96, 120, 162 Volk, Alexander, 123 Zojer, Karin, 130, 168 von Smekal, Lorenz, 47 Zollfrank, Cordt, 157 Vörös,Zoltán,160 Zotter, Franz, 66 Zöttl,Samuel, 146 W Zoubi, Hashem, 78 Wagner, Jochen, 167 Wagner, Margareta, 124, 130, 170 Wagner, Thorsten, 129 Wallner, Anton, 41, 42 Waltenberger, Wolfgang, 43 Wang, Xiangzun, 53, 149, 152 Wang, Zhiming, 118, 127, 176 Wankhammer, Alexander, 65 Waubke, Holger, 67 Weber, Frederik, 177 Weber, Hansjörg,170 Weihs, Gregor, 160 Weihs, Philipp, 167 Weinert, Michael, 128 Weiss, Ingrid, 158 Werzer, Oliver, 96 Widmann, Eberhard, 40, 41 Wieninger, Thomas, 51 Wild, Eva-Maria, 42 Williams, Richard, 46, 49 Windholz, Laurentius, 82, 144, 145 Windisch, Andreas, 48 Winkler, Adolf, 130, 168, 173–175 Winkler, Georg, 147 Winkler, Stephan, 41, 112, 153 Wolfberger, Archim, 177 Wollboldt, Petra, 170 Wunderlich, Rainer, 98 Wünschek, Barbara, 40 Würschum, Roland, 94, 98

Y Yarema, Maksym, 87, 88 Ystad, Sølvi, 68

Z Zaheer, Uddin, 82 Zallo, Eugenio, 86 Zandvliet, Harold, 123 Zankel, Armin, 122 Zannoni, Claudio, 162 Zawisky, Michael, 152 Zechner, Andrea, 166 Zederbauer, Tobias, 92, 160 Zeppenfeld, Peter, 129, 168 Zhang, Jianjun, 155 Zharnikov, Michael, 162 Ziegelwanger, Harald, 69 Zimmerling, Martin, 135 Zmeskal, Johann, 40, 41 185 186 15 Maps i C 63 F ReSoW 63 main building Hauptgebäude UniGraz@Museum Physics HS 05.01 58 63

187 188

Programme of the 62nd Annual Meeting ÖPG 2012 Tuesday, 18th September Wednesday, 19th September Thursday, 20th September Friday, 21st September Registration: 9:00 – 16:30 Registration: 08:30 – 16:30 Registration: 08:30 – 16:30 Registration: 08:30 – 12:00 9:00 – 10:00, HS 15.03 Plenary Talk 9:00 – 11:00 John Swain (Boston) Parallel Sessions 9:00 – 11:00 Cosmic Rays: An Ongoing Clear Window Parallel Sessions into New Physics AKU: LS 15.02

FAKT: HS 15.03 A 10:00 – 11:00, HS 15.03 AMP: LS 15.01 FAKT: HS 15.03 FKP+NESY: HS 15.12 u Plenary Talk OGD: HS 15.02 s FKP+NESY: HS 15.12 t r Franz Gießibl (Regensburg) B

OGD: HS 15.02 i a Simultaneous atomic force- and u h U n scanning tunneling microscopy i l 10:00 12:45, HS 15.03 t – d

t n P p 11:00 11:20 i – i 11:00 – 11:30 11:00 – 11:30 n v Energietag : h / g L e

Coffee break / Coffee break Coffee break y w

“Mehr Licht” r 1 s s w 11:20 – 12:30, HS 15.03 11:30 12:30, HS 15.03 c

– 5 i AKE, PIE i c t a w , Prize Awards Ceremony y

Plenary Talk a t

R Fritz Kohlrausch Prize, Victor Franz Hess Prize, . i o l 11:30 13:30 o Vahid Sandoghdar (Erlangen) – o

Anton Paar Prize, Max Auwärter Prize, e f S e n On the efficient interaction of single

Roman Ulrich Sexl Prize, Young Physicists’ Tournament, Parallel Sessions S G p Physics Olympiad, Physik-Fachbereichsarbeiten photons and single emitters o o FAKT: HS 15.03 g c r a W . i

FKP+NESY: HS 15.12 a 12:30 – 13:30 12:30 – 13:00 e 12:45 – 13:30 z t i t OGD: HS 15.02

Lunch break Lunch break y

Lunch C

13:30 – 14:30, HS 15.03 13:00 – 14:30, HS 15.03 Ö Prize Winner Talks Careers in Physics P Fritz Kohlrausch Prize HS 15.03 G 13:30 – 16:00, HS 15.03 Max Auwärter Prize Roman Ulrich Sexl Prize GEP: HS 05.01 ÖPG Scientific Commitees Energietag 13:30 – 16:00 14:30 – 15:30, HS 15.03 14:30 – 15:30 FAKT LHS and ÖPG Working Groups “Mehr Licht” Plenary Talk Parallel Sessions

HS m HS 15.02 Hans Briegel (Innsbruck) AKU, AMP, FAKT, FKP+NESY, OGD ACP: Equal Opportunities in Physics

Quantum physics, simulation, 15.02 i MBU: SR 15.15 c and computation AKE: Energy o h e +

AKU: Acoustics a

15:00, SR 15.15 15:30 – 16:00 15:30 – 15:50 p + e M

AMP: Atoms, Molecules, Quantum g 4 ÖPG Board meeting l

Coffee break Coffee break . 2 i r c Optics and Plasmas 3 O a 0 h

3 m 16:00 – 16:45, HS 15.03 FAKT: Nuclear and Particle Physics 1 a LHS r 1 2 g e

Wolfgang Adam FKP: Solid State Physik s 6

HS @ a l e

The Higgs Boson search at the LHC:

GEP: History of Physics n R y 16:30 – 17:00, HS 15.03 15.02 15:50 – 18:00 3 results and perspectives u i @ 8

LHS: Physics in Schools a z Opening Parallel Sessions n 0 m e MBU: Medical Physics, Biophysics, i u -

17:00 18:00, HS 15.03 AKU, AMP, FAKT, FKP+NESY, g

– 5 s 16:45 – 17:45, HS 15.03 Environmental Physics n r e 2 GEP, OGD, MBU i Plenary/Public Lecture a ÖPG General Assembly - y NESY: Research with Neutron and 0 g z

James Cronin (Nobel Laureate) 3

of Members r Synchrotron Radiation . a Spontaneous Ionization to Subatomic Physics: a z Some Vignettes from Cosmic Ray History OGD: Surfaces, Interfaces, and t .

Thin Layers a 17:45 – 20:00 18:00 – 20:00 PIE: Physics - Industry - Energy t Poster Session Refreshments at the PMP: Polymer Physics UniGraz@Museum 19:00 Reception 20:15 – 21:15 Location: Rathaus Graz Theatre, HS 05.01 “Kosmische Strahlen: Das Leben des Victor F. Hess”