www.cnr.it/neutronielucedisincrotrone NOTIZIARIO Neutroni e Luce di Sincrotrone Rivista del Consiglio Nazionale delle Ricerche

Cover photo: Contour plot and projection of the SUMMARY time-average muon polarisation in

silver (I) oxide, Ag2O as a function of applied magnetic field and temperature. From this, detailed EDITORIAL ...... 2 information about the muon state electronic structure in this material, C.J. Carlile can be deduced, informing by analogy on the states adopted by . Twenty-Years Italian/Anglo Science Collaboration to Continue...... 3 C. Andreani and R.S. Eccleston

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0.1 SCIENTIFIC REVIEWS The Research Scene of Femtosecond 3000 X-ray Diffraction...... 4 2000

160 1000 120 P. Bergese and L.E. Depero 80 40 Magnetic Nanostructures studied by polarised Il NOTIZIARIO is published by reflectometry: recent results and future CNR, and printed in collaboration prospects for polarised reflectometry at ISIS...... 13 with the Facoltà di Scienze M.F.N. R.M. Dalgliesh and S. Langridge andNOTIZIARIO the Dipartimento di Fisica of the UniversitàNeutroni e Luce didegli Sincrotrone Studi di Roma “Tor Vergata”. The infrared Beamline SISSI at Elettra ...... 23 Vol. 9, N. 2 July 2004 Autorizzazione del Tribunale di S. Lupi, A. Nucara, L. Quaroni and P. Calvani Roma n. 124/96 del 22-03-96

DIRECTOR: Complex dynamics in polymer electrolytes ...... 32 C. Andreani A. Triolo, O. Russina, M. Lanza and H. Grimm

EDITORIAL BOARD: M. Apice, P. Bosi

SCIENTIFIC BOARD: µ ...... 38 L. Avaldi, F. Aliotta, &N &SR NEWS F. Carsughi, G. Paolucci

SECRETARY: MEETING AND REPORTS ...... 48 D. Catena

CONTRIBUTORS TO THIS ISSUE: M. Capellas Espuny, CALL FOR PROPOSAL ...... 49 G. Cicognani, R.S. Eccleston, D. Herlach, P. King, P. Mikula, A. Schreyer, R. Willumeit CALENDAR ...... 50

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Vol. 9 n. 2 July 2004 EDITORIAL

ver the last two years the world of neutron scatter- tron scattering in Europe? Firstly, the realization that the ESS ing (or at least the European part of it) has been ad- will not be funded “tomorrow” means we have had to focus justing itself to a new scenario. Up until 2002 it was in on our current sources and make the best of the consider- O “business as usual” with Europe’s neutron sources able resources which we already have. There are some in Eu- upgrading their facilities incrementally as and when funds rope who feel we should invest in the SNS as a preparation were available and the user community was expanding, for ESS. I am not of this opinion. Instead the scarce capital re- slowly but surely, and moving into wider scientific areas. sources which we do have would be better invested in Euro- The European Source was still a realistically at- pean facilities, in a manner similar to the American policy tainable dream. The new scenario began to dawn, paradoxi- when the Brookhaven reactor shut down. Whilst specialist cally, at the Bonn ESS meeting in the light-filled halls of the neutron scientists in Europe might wish to gain experience new German parliament building, now relieved of its origi- on high-power spallation sources there is little risk that the nal purpose thanks to a different change of scenario. At this user community as a whole will migrate west (or east). meeting in June 2002 the ESS laid down a challenge to the Therefore we have to invest in our own sources to maintain funding bodies of Europe and relaunched itself. The meet- the health of our considerable user community. ing was a huge success for , enjoyed by all In order to address this question, the ILL, for its part, is re- in a festival atmosphere, but not, at least in the short term, examining its investment and infrastructure renewal pro- for the ESS. It was time for funding bodies to say what they gramme – the Millennium Programme – so as to position hadn’t wanted to say before. To paraphrase “We do want ourselves better in this new scenario. There are areas where the ESS, but not now. Instead we should be investing in the the ILL is pre-eminent and it is these areas upon which we world-class sources which we have already and let’s see must concentrate. Examples which spring to mind are: how the American and the Japanese get along with their big where intense beams of cold are needed as in the projects before we take the plunge”. case of high resolution ; where large focusing But where was the money to come from to invest in Eu- monochromators and large position sensitive detectors can rope’s current world-leading sources ? Just when science in be used on instruments such as powder diffractometers; Europe appeared to be in the doldrums a strange thing hap- where broad wavelength band beams can be used such as pened, at least it appeared strange to normal mortals. In Lis- for small angle scattering, neutron echo, and single bon at the EU Heads of Governments meeting a pledge was crystal diffractometers employing image plates; where beam made to turn Europe into “the most dynamic knowledge- reliability and predictability is valued and where beam sta- based economy in the world by 2010”. And then an even bility is essential for liquid diffraction for example or for ki- stranger thing happened – a pledge at the next meeting in netic experiments; where raw intensity is needed including Barcelona to increase the proportion of European GDP almost all applications involving nuclear physics, or for to- spent on research and development from the 1.8% current mographic imaging. Equally well the employment of polar- average to 3.0% by 2008-2012. A lot of credit for these initia- ized neutron techniques – polarized helium-3, polarizing su- tives must go to Monsieur Philippe Busquin, who has been permirrors, polarizing monochromators (Heuslers), spheri- an excellent European Commissioner for Research, who had cal polarimetry (Cryopad), all developed or perfected at ILL earlier launched the grand idea of a European Research – is better suited, experience tells us, to continuous beams. Area, and who was quoted as saying last month “No agri- There are clear signs that our funders – owners and scientif- culture, but science, education and innovation, are needed ic partner nations alike - have recognized this message and to achieve the Lisbon goal”. What can be happening in Eu- are responding. The prospects for further scientific partners rope? Someone speaking the unspeakable – “not agricul- in the Institute also look good. The full Europeanisation of ture”! The ERA spawned the idea of a European Research the ILL is a necessary step in my view. In these ways, for a Council – initially dismissed by many but now being talked relatively small outlay, the 1.5 B capital investment which about as having a budget of 10 B over seven years and the ILL represents can be enhanced and optimized in order awarding grants to European researchers on the grounds of to help maintain scientific leadership in this field for Europe excellence only. No juste retour! Neutron scatterers are good for the next 15 years at least. The other powerful neutron fa- at applying for grants so this appears to be a positive move. cilities in Europe will of course also play their part. At that The European Strategy Forum on Research Infrastructures time an operational ESS, complementary to ILL, would be created itself just over 2 years ago and its first task was to ex- needed. In the meantime we are pleased to announce that amine the case for neutrons in general and the ESS in particu- the ESS Initiative will relocate to the ILL in order that they lar. But ESFRI has no direct collective authority for funding, maintain a watching brief, enhance the scientific case and being composed of sets of delegations from the 15 original launch a bid for funds at an appropriate moment. EU countries and now expanded to 25 plus Switzerland. We are of course happy to have such an obvious Italian Nevertheless its pronouncements carry weight, differing ac- presence at the ILL and indeed at our partner Institutes ES- cording to whether they are positive or negative. A positive RF and EMBL. We were honoured by the visit of the Italian recommendation can be agreed upon by all but there is little Senatorial Committee on Science, Education and Culture in means of acting upon it. A negative recommendation howev- May of this year. Such interactions are of mutual benefit er can seriously jeopardise a project. There are signs that DG and enhance the appreciation of all concerned. Research in Brussels wishes this state of affairs to evolve but C.J. Carlile currently no consensus has been reached. Institut Laue Langevin, 6 rue Jules Horowitz So the scenario has changed, but how might this affect neu- 38042 Grenoble Cedex 9 - France

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TWENTY-YEARS ITALIAN/ANGLO SCIENCE COLLABORATION TO CONTINUE

Scientists from the UK and Italy have signed an agreement which builds on a close and very successful collaboration that has lasted for 20 years. Professor Adriano De Maio, president of the Consiglio Nazionale delle Ricerche (CNR - the Italian Na- tional Research Council) and Professor John Wood, Chief Executive of CCLRC, signed a Memorandum of Understanding agreeing to collaborate on the development of new technologies and instrumentation. «The continuing success of this 20-year agreement is very important for us» explained Professor De Maio. «First and most impor- tantly to enable excellent scientific research to take place, but also for many less obvious reasons. Building the neutron instruments at the CNR and on the ISIS facility has enabled great leaps in technical innovation and know-how, increasing industrial competitiveness in the two countries». Professor Wood was also enthusiastic about the future. «We have to look to the future and coordinate strategy for the new facilities coming on line. We need to make sure new facilities, like the new target station on ISIS - which we’ll start building later this yea - offer complimentary opportunities for scientist, making them stronger and better able to compete with similar facilities outside Europe». Recent examples of research initiatives that have benefited from this collaboration include investigation on ISIS of candidate hydrogen storage technologies, and Italian archaeological specimens - helping scientists understand how, and from what they were constructed.

Notes for editors

Italian scientists have had access to several ISIS instruments The CCLRC (Council for Central Laboratory of the Re- over the 20 years, starting with Prisma in 1984, through search Councils) is a research council. It operates world- µSR, EMU, TOSCA, VESUVIO, and looking to the future, leading facilities on its three sites: the Rutherford Appleton NIMROD on ISIS’s second target station which should be Laboratory in Oxfordshire, the Daresbury Laboratory in available in 2008. Cheshire and the Chilbolton Observatory in Hampshire, at The Italian National Research Council (CNR) is a public or- which scientists carry out research across a wide range of ganization of great relevance in the field of scientific and topics in science and engineering. It is one of Europe’s technological research of the Country whose original insti- largest multidisciplinary research organisations supporting tution goes back to year 1923. It promotes and carry on re- scientists and engineers world-wide. It operates world-class search activities, in pursuit of excellence and strategic rele- large-scale neutron, muon, synchrotron and high-powered vance within the national and international ambit, in the laser facilities. Programmes span a wide range of science, frame of European cooperation and integration; in coopera- engineering, and technology, including: materials science, tion with the academic research and with other private and physics, chemistry, mathematics, life sciences, computer sci- public organizations, ensures the dissemination of results ence, particle physics, space science, instrumentation, accel- inside the Country. erator-based technologies, IT and e-Science.

C. Andreani & R.S. Eccleston

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Paper received March 2004 THE RESEARCH SCENE OF FEMTOSECOND X-RAY DIFFRACTION

Paolo Bergese and Laura E. Depero* INSTM and Structural Chemistry Laboratory, University of Brescia, via Branze, 38, 25123, Brescia (Italy)

If your only instrument is an hammer, have been related to steady-state, long-lived systems. you will end up to treat everything as a nail Extension of the X-ray techniques into the time domain L. M. KRAUSS can dramatically contribute to the understanding of the mechanisms of formation and transformation occurring Femtosecond time-scale phenomena are usually inves- in material systems and to make a bridge between their tigated by optical pump/probe experiments. However, structure and dynamics. Time-resolved XRD is an excel- this approach does not generally give direct informa- lent tool to study the intra- and intermolecular structur- tion on the system molecular structure. Time-resolved al changes, and also finds use in a number technologi- X-ray diffraction (XRD) is the candidate probe for cal applications, such as lithography. The time resolu- achieving this target, and opens the study of femtosec- tion of the experiments must cover many orders of ond transient structural transformations. Presently, magnitude, as the processes themselves have key-times femtosecond time-resolved experiments constitute the (the time range in which a transient structural interme- cutting-edge of XRD. diate occurs) spanning from tenths of femtoseconds up The successful results of the past five years aroused in- to kiloseconds. creasing interest and expectations in the material science The conventional way to study the dynamics of ultrafast community, especially in the perspective of the realiza- phenomena is by optical pump/probe experiments. tion of very-high brilliance X-ray sources, which, in the Such techniques do not directly give the positions of the case of free electron lasers, are expected to reach 1033 atoms as a function of time except that in very photons/(s⋅mrad2⋅mm2⋅0.1%bw) at a wavelength of 0.1 favourable cases. To the contrary, time-resolved XRD can nm. The aim of this paper is to outline recent achieve- in principle provide a direct probe for atomic-scale fast ments and ongoing projects in femtosecond X-ray ma- dynamic processes, opening the study of transient struc- chines and pulse generation, to assess the existing litera- tural reactions [2]. ture, and, finally, to make a tentative census of the An ideal time-resolved XRD experiment should have groups working on femtosecond XRD and of their main sufficient temporal and spatial resolution to track the se- research activities. quence of transient events of interest in the observed process. Rapid thermal events, polymorphic phase tran- Introduction sitions, and shock-wave propagation occur at a time The interaction between a monoenergetic X-ray beam scale of 10-100 picoseconds. However, to follow vibra- and the electronic distribution of a crystalline material tions and rotations in single molecules, liquids or crystal results in a well defined X-ray scattering pattern. The lattices, and breaking and formation of chemical bonds, scattering pattern reflects in a macroscopic environment a resolution better than 300 femtoseconds is needed [3]. the order of nuclei within the material in terms of both Moreover, the range of internuclear distances in mole- spatial orientation and position. Thus, it is highly sensi- cules requires a spatial resolution of approximately 1 Å, tive to the material crystal structure and microstructure. which for diffraction requires (hard) X-ray of compara- For these reasons, from nearly a century, X-ray diffrac- ble wavelengths. tion (XRD) is one of the major probes in molecular struc- Femtosecond time resolution and hard wavelengths (1) ture determination and has been used to study the struc- are not the only requirements (and difficulties) placed on tural and microstructural properties of crystalline (and, femtosecond XRD probes. In addition, the X-ray source to some extent, amorphous) materials. Modern tech- must have (2) enough brightness, and must be (3) spec- niques of X-ray production, their interaction with matter trally concentrated and (4) spatially collimated, and (5) and the inherent applications, with special attention to synchronized with the (optical laser) pump sources. All XRD, can be found in a recent monograph by Nielsen of these aspects contribute to the experimental chal- and McMorrow [1]. lenges of femtosecond XRD. Indeed, femtosecond (also Most of the XRD studies and other X-ray applications referred in the literature as ultrafast) X-ray pulses pro-

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duction and application constitute the cutting-edge of Femtosecond X-ray sources time-resolved XRD. Synchrotron methods Also femtosecond X-ray absorption, being an “unparal- Synchrotrons have become dramatic tools in X-ray sci- lel” tool of X-ray diffraction, plays an important role in ence. These machines accelerate and store relativistic the study of transient intermediates. Femtosecond X-ray electrons in a ring and use them to emit X-rays from in- absorption is performed with the same sources of X-ray sertion devices and bending magnets. The shortest time pulses used in femtosecond XRD. Nevertheless, deeper resolution which is attainable with the latest (third) gen- treatment of the subject is out of the scope of this paper, eration of synchrotrons is equal or higher than 30 pi- and exhaustive basics can be found in references [1] and coseconds [7,8]. Femtosecond time resolution has been [4]. Other emerging femtosecond time-resolved charac- the challenge for which novel approaches have been de- terization techniques, not developed here, are X-ray fluo- veloped. rescence [5] and electron diffraction [6]. One of the earliest efforts to generate femtosecond X-rays The natural application of femtosecond XRD is in mater- from relativistic electrons was based on scattering a ul- ial science, because this is the time limiting scale on trahigh intensity femtosecond laser pulse with a rela- which structural dynamics occur. Investigation of ultra- tivistic electron bunch (Thomson scattering). In this ap- fast dynamic properties of condensed matter systems proach, the laser effectively acts as a transient ondulator will facilitate the understanding of phenomena such as for the electrons, and under the proper scattering geome- bulk and surface melting and dynamics, or dynamic be- try, the duration of the generated X-ray burst is deter- haviours of grains (nanoscale tribology). mined by the laser pulse duration. For a detailed descrip- For physical chemists, the direct observation of the mol- tion of the Thomson scattering approach in femtosecond ecular structure of the intermediate conformations be- X-rays generation, the characteristics of the X-rays, and tween reactants and products has been a major goal how they depend on electron and laser beam properties since the formulation of Eyring’s transition-state theory and scattering geometry see the work by Schoenlein et al (1930). The transition states last about 100 femtoseconds, [9]. The first experiment was realized at Berkeley Nation- as dictated by the time scale of an atomic vibrational pe- al Laboratory in 1996 using the existing 20 picoseconds riod. Thus, femtosecond XRD opens the possibility to in- linac with an electron energy of 50 MeV [10]. They suc- vestigate structural properties of molecules during ceed to produce about 105 X-ray photons at 0.4 Å and the chemical reactions at the kinetics time rate. Examples in- duration of the X-ray burst was 300 fs. This X-ray flux clude organic solids dynamical behaviour, photo-in- was high enough to study the ultrafast structural dy- duced order/disorder phenomena in organic conduc- namics of crystals (InSb) following femtosecond laser tors, and polymerisation. pulse excitation by time-resolved X-ray diffraction [11]. In structural biology femtosecond XRD provides the Together with Berkeley, the Thomson scattering ap- possibility to investigate a class of molecules presently proach is presently being pursued at several laboratories not accessible for structural determination. High bril- in the USA (Brookhaven Natl. Lab. [12] and Thomas Jef- liance sources will allow to obtain data from these mole- ferson accelerator facility [9]), and Japan (High Energy cules in the very small time window before they are Accelerator Res Org, Tsukuba. [13,14]). damaged. Using this technique on the smallest creatures An alternative method for generating femtosecond X- capable of self-replication (such as mycoplasmas) it rays is to gate them from long-pulse X-ray sources. This seems possible to observe the processes by which they approach is feasible with the brightest sources of X-rays perform their tasks. presently available, such as the Advanced Light Source The aim of this paper is to outline recent achievements (ALS), the Advanced Photon Source (APS), and the Eu- and ongoing projects in femtosecond X-ray machines ropean Synchrotron Radiation Facility (ESRF). and pulse generation, to make a comparative analysis of The technique uses a femtosecond optical pulse to gener- the existing literature, and, finally, to list the main ate femtosecond X-rays from a storage ring. A femtosec- groups working on femtosecond XRD and their princi- ond optical pulse of moderate energy (about 0.1 mJ) pal research activities. We will concentrate on femtosec- modulates the energy of an ultrashort slice of a stored ond XRD, as it is the actual XRD frontier. An exhaustive electron bunch as they propagate through a wiggler. The monograph on experimental and theoretical aspects of energy-modulated electron slice spatially separates from picosecond XRD was edited in 1997 by Helliwell and the main bunch in a dispersive section of the storage Rentzepis [7]. Theoretical aspects of interactions between ring and can then be used to generate femtosecond X- ultrafast X-ray pulses and matter will not be treated rays at a bend-magnet (or insertion-device) beamline. here; again some basics can be found in the monograph The original electron bunch is recovered due to synchro- by Helliwell and Rentzepis [7] and in the references indi- tron damping of the electrons in the storage ring. Thus, cated in Table 1. other synchrotron beamlines are unaffected and special

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operation of the storage ring is not required. For a de- starting from noise. In this way the FEL generates 200 tailed description of the method see reference [9]. femtoseconds long bunch trains of Fourier-transform- In the context of femtosecond X-ray production, 30 pi- limited and extremely intense spikes with strongly fluc- coseconds synchrotron pulses may be considered as a tuating intensities. The radiation has the optical proper- continuous beam that can be stroboscopically resolved ties characteristic of conventional lasers, in particular with an appropriate X-ray detector (streak camera) in or- high spatial coherence. FEL differs from conventional der to achieve a femtosecond resolution. The detector is lasers in using a relativistic electron beam as its lasing equipped with an ultrafast shutter system, whose open- medium, as opposed to bound atomic or molecular ing time and frequency must match the time structure of states, hence the term “free-electron”. the storage ring as well as the desired timing sequence of The first FEL was built in 1977 at 10 mm radiation wave- the experiment. At the ESRF a complete experimental length. However, only the idea of SASE opened the path system with synchronization of a 100–150 femtoseconds to use a FEL as a source for X-rays. The radiation wave- laser, synchrotron, rotating chopper and streak camera is lengths produced by (SASE) FEL currently span from in- now operating. This set up allowed to study the lattice frared to soft X-rays [19,20] and several projects to ex- expansion of laser-excited metal nanoparticles [15]. More tend them to hard X-rays are going on. At the TESLA details on streak cameras technology and experimental Test Facility (TTF) of HASYLAB/DESY (Germany), it methods can be found on the leading paper on the sub- has been set up the project of a XFEL that generates soft ject published in 1997 by Michael Wulff [16]. X-ray mrad collimated pulses with 30 femtoseconds of The drawback of streak cameras is the low sensitivity duration, with an average brilliance of 1022 (on the order of 0.1%). In combination with the fact that photons/(s⋅mrad2⋅mm2⋅0.1%bw), with the average num- only a small fraction of the X-ray pulse is actually used, ber of photons exceeding 1012 photons/pulse [21]. The this gives a severe limit in the number of detected pho- target XFEL at TESLA is a machine able to generate 100 tons, which can be partially compensated by accumula- femtoseconds X-ray collimated beams (few µrad) as tion. A time resolution lower than 300 femtoseconds may bright as 1033 photons/(s⋅mrad2⋅mm2⋅0.1%bw) at a wave- be reached in the forthcoming years for one shot experi- length of 0.1 nm. This brilliance represents more than ten ments. Developments at ESRF have recently led to an ef- order of magnitude of what the current synchrotrons can fective time resolution of 460 femtoseconds and 640 fem- produce with polychromatic 50 picoseconds X-ray bursts toseconds, for accumulation times of 1 second (900 [22,23,24]. Another project for the construction of a shots) and 1 minute (54 000 shots) respectively [8]. XFEL, targeted to three spectral bands: the first around Other methods for generating sub-picosecond X-ray 40 nm wavelength, the second around 10 nm and the pulses from synchrotron have been proposed. The first is third in the soft X-ray region (1.5 – 1.2 nm), is underway based on nonthermal melting of crystals, a reversible in Italy at the Synchrotron Light Laboratory ELETTRA transition that occurs below the damage threshold. Non- [25]. Finally, in Japan, at the SPring-8 Synchrotron Facili- thermal melting of a Bragg crystal can interrupt X-ray ty, a XFEL (SCSS: SPring-8 Compact SASE Source) is un- diffraction, which is subsequently reactivated by recrys- der construction, and hard X-ray (0.1 nm) is the wave- tallization. Then, in principle, by combining two crystals length expected to be achieved in the year 2010 [26]. in series and varying the time delay between their melt- A worldwide and updated report on FEL researches and ing/recrystallization cycle, a slice of X-ray radiation projects can be found on the “World Wide Web Virtual could be cut [17]. Library: Free Electron Laser research and applications” The second approach relies on the scattering of hard X- [27], and a Round Table for synchrotron radiation and ray photons by a superlattice of optical phonons gener- FEL, funded by the European Commission, exists [28]. ated by ultrafast laser pulses incident on a Bragg crystal. Using a suitable laser system, the crystal lattice motion Laser-produced plasma (LPP) X-rays can be controlled so that efficient Bragg diffraction is The idea to study the laser-plasma X-ray emission was switched on and off in a time comparable to a phonon born in the field of laser fusion. The motivation was to oscillation period (100 – 1000 nanoseconds) [18]. study the X-ray emission as it is one of the most rich sources of information for understanding the basic phe- X-ray free-electron laser (XFEL) nomena of laser-plasma interactions. From these exper- The free-electron laser (FEL) is a (fourth generation) iments it was straightforward to use it on the flip side, source for femtosecond X-ray pulses. A strongly i.e. to generate X-rays pulses from laser-produced plas- bunched and highly intense electron beam is sent ma (LPP). through a long ondulator placed after a linear electron The energy deposited at the surface of a solid-state tar- accelerator. Under certain challenging conditions self- get produces a high temperature (500 eV) and dense amplified spontaneous emission (SASE) takes place plasma which remains at near solid densities during the

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interaction because it has no time to expand. In such search subject, and its area is proportional to the number plasmas, high ionisation stages of ions are reached and of papers dealing with that subject. strong non-equilibrium states are produced. At laser Table 1 and Figure 1 suggest that most of the papers peak power intensities (around 1000 W/cm2), strong (both applicative and theoretical) have been focused on non-linear processes accelerate some electrons of the the machines and methods for the production of fem- plasma to a few tenths of keV. These fast electrons pene- tosecond X-ray pulses. To date, the major number of ap- trate inside the solid target deeper than the plasma plicative experiments with femtosecond XRD probes has depth and loose their energy mainly by K-shell ionisa- been performed in the field of the physics of (con- tion of the atoms, which then rearrange emitting mono- densed) matter, mainly using LPP X-ray sources, and chromatic K X-ray radiation. fewer times with synchrotron methods. Whit the same Yet in 2000, at LOA of ENTSA (France) the efficiency of sources also a couple of experiments were realized in the LPP X-ray source was about 109 photons/pulse at a physical chemistry, while applications in structural biol- wavelength of about 0.7 nm [29]. Presently, LPP are the ogy are still at the level of theoretical previsions. XFEL most intense, cheap and compact sources of hard X-rays machines and related experiments are at the project at the time scale of few hundreds of femtoseconds. In- stage. The hard problem of the detection of femtosecond deed, most of the experiments in which femtosecond X-ray pulses is more or less deeply treated in all the pa- transient events were tracked by time resolved XRD pers, especially in the ones dedicated to synchrotron used this kind of sources (see the next Section). methods (actually, some of them relies on streak camera Recently, soft X-ray bursts produced by the laser-plasma detectors, see the previous Section). However, a paper technology touched the attosecond frontier [30,31], such dedicated to this specific topic exists. performances have also been theoretically predicted for Finally, it may be noted that the number of review pa- machines based on synchrotron non-linear Thomson pers (even excluding the present one) exceeds the num- scattering [32] as well as for XFELs [33]. ber of application papers (!). The positive message is that femtosecond XRD is a cutting-edge research field also X-ray lasers from the scientific fashion standpoint. X-ray lasers are very promising, but at the present stage of development they are still not applicable as routine Who does what in the scene of femtosecond X-ray diffraction femtosecond radiation sources. They can be seen as the Femtosecond XRD is a young, frontier research. Fem- implementation towards pulsed X-ray production of the tosecond X-ray sources development is stimulated by ex- conventional laboratory X-ray tubes. Here X-rays are perimental applications, and viceversa. Thus, the re- produced as a result of the ionization driven by a fem- search groups working on the subject include at their in- tosecond laser of core level electrons of the atoms of a side both the aspects, instead of focusing on one of them, target This sources display several advantages, includ- as usually happens in more mature disciplines. The fol- ing very low costs (if compared with the other femtosec- ond X-ray sources), compactness (laboratory, tabletop in- struments), and manageability (they work at near-room temperature). More details on X-ray lasers can be found in the works by Guo et al. [34] and by Egbert et al. [35], and in the references cited in the next section.

Comparative analysis of the literature on femtosecond XRD We conducted a comparative analysis of the published scientific papers concerned with femtosecond XRD. They were searched by the ISI Web of SCIENCE and the resulting list (updated at 24 March 2004 and ordered by the “times cited” criterion) containing the full references and titles of the papers is reported in the Appendix of this work. Analysis results are summarized in Table 1 and Figure 1. They were built to stress the subdivision by subject of the papers. In Table 1 each number corresponds to a pa- Fig. 1. Bubble plot of the subdivision by subject of the scientific papers concerned with femtosecond XRD. Each bubble refers to a research sub- per, with reference to the list in the Appendix. Figure 1 is ject, and its area is proportional to the number of papers dealing with the bubble plot of Table 1: each bubble refers to a re- that subject. The plot is built on the data of Table 1.

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lowing list, probably far to be complete, includes the the websites of these groups can be found at the website main research groups working on femtosecond XRD that of the TMR Network [37]. we extrapolate by crossing web and scientific papers in- The main groups working on X-ray lasers are the ones formation. that produced the papers indicated by Table 1. In Europe it is going on a coordinated research project Ultrafast X-ray machines (financed in the frame of the 5th Framework Programme) At HASYLAB/DESY laboratory, in Germany, a (X, on femtosecond X-ray sources (FAMTO: ultra-fast atom- XUV)-ray FEL specifically designed to deliver 100 fem- ic movie tools 100 femtosecond time-resolved diffraction toseconds X-ray pulses is under construction [22,23,24]. installations for the study of ultrafast transient structural Projects for the realization of (X, XUV)-ray FELs are also changes) [39]. The project is managed by Antoine Rousse underway in Italy (Synchrotron Light Laboratory ELET- of ENSTA. TRA [25]) and Japan (SPring-8 Synchrotron Facility [26]). Studies in synchrotron methods for femtosecond genera- Application of Ultrafast X-rays tion of X-ray pulses are going on in USA (Berkeley Na- The groups indicated in the previous Subsection gather tional Laboratory [9], Brookhaven National Laboratory the world leaders in femtosecond XRD. Here it follows a [12] and Thomas Jefferson accelerator facility [9]), Eu- list of the group leader researchers and (only) their main rope (European Synchrotron Radiation Facility, ESRF) applicative interests in femtosecond XRD. Owing to the [8], and Japan (High Energy Accelerator Res Org, Tsuku- highly cross-disciplinary nature of the subject and the di- ba) [13,14]. mensions of each group these are strong limitations, but LPP (X, XUV)-ray sources are developed in the USA at necessary for compiling a rough, yet indicative, list. the Ultrafast structural dynamics of matter laboratories (Scool of Optics/CREOL, Un. of Central Florida) [36]. In EUROPE Europe it exists an institution that brings together a Thomas Tschentscher (HASYLAB/DESY, Ge): (X, XUV)- number of European research groups and institutions ray Free Electron Laser, femtosecond X-ray LINAC; who work together to develop and apply (sub)-picosec- Richard P. Walker (ELETTRA): (X, XUV)-ray Free Elec- ond LPP X-ray pulses: the TMR Network [37]. The group tron Laser; Stephane Sebban, Antoine Rousse (LOA, includes the applied optical laboratories of ENSTA [38] France): Laser-plasma (X, XUV)-ray sources; Justin Wark and other academic groups (Jena, Saclay Lund, Essen, (Oxford, GB): theoretical aspects of X-ray diffraction on Salamanca, Berlin, Pisa Palaiseau-LULI). All the links to femtosecond timescales; Jorgen Larsson (LLC/Max-Lab,

Physics of matter Physical chemistry Structural biology Machines

Synchrotron 42, 44, 76 7 19, 23, 32, 35, 39, 41, methods 50, 59, 66, 93

LPP X-rays 1, 2, 3, 4, 9, 12, 13, 14 8, 28, 31, 43, 45, 46, 34, 37, 38, 78, 85 53, 57, 61, 73, 88, 90, 91

X-ray lasers 42 20, 22, 25, 36, 51, 54, 56, 63, 70, 80, 83, 87,89

XFEL 64

Theoretical 30, 68 29 5, 11, 27 15, 16, 17, 26, 33, 40, 49, 58, 62, 75, 94

Reviews 6, 10, 18, 21, 47, 48, 55, 60, 65, 67, 72, 74, 77, 84, 86, 92

Detectors 69

Tab. 1. Scientific papers concerned with femtosecond XRD subdivided by the main treated research subject. Each number corresponds to a paper and refers to the list, where the full references and titles of the papers are given, which is reported in this work Appendix. The list was compiled by the ISI Web of SCIENCE‚ and is updated at 24 March 2004.

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Se): Synchronization in ultrafast X-ray experiments; I. femtoseconds X-ray pulses with a very-high brillance. Uschmann (Jena, Ge): X-ray optics for femtosecond ex- Indeed, 100 femtoseconds and shorter X-ray pulses can periments; Ph. Zeitoun (LIXAM/LOA, Fr): XUV-ray op- now be produced from LPP X-ray systems. These ma- tics for femtosecond experiments; Markus Drescher chines have actually been the first to allow the observa- (bielefeld, Ge): Atomic dynamics with ultrafast XUV ra- tion of transient events in the femtosecond time-scale diation; Faris Gelmukhanov (Stockholm, Se): Ultrafast with XRD, and have been, to date, the most employed in dynamics of relaxation & fragmentation processes; Si- such experiments. In the future, femtosecond XRD (and mone Techert (Göttingen, MaxPlanck, Ge): Applications other femtosecond time resolved X-ray investigation of ultrafast X-rays in chemistry; Richard Neutze (Göte- techniques) will find wide application in a broad and in- borg, Se): Ultrafast X-rays in Biology; Michael Wulff (ES- terdisciplinary area of science, including condensed mat- RF, Fr): Time-resolved studies of molecular structures ter physics, chemistry, biology, and engineering. The and crystallography; Klaus Sokolowski-Tinten ability to time-resolve at the femtosecond level could (Essen, Ge): Solid-(solid, liquid) phase transition; Eric open up entirely new fields of scientific research. Collet (Rennes, Fr): Photoinduced structural phase trans- Until today the research has been mainly focused on the formations; H. Durr (Bessy, Ge): Ultrafast magnetic designing of femtosecond X-ray sources and on the processes; Janos Hajdu (Uppsala, Sve): time-resolved study of dynamic properties of (crystalline) condensed XRDX in structural biology; H.P. Trommsdroff (Greno- matter (mainly by monitoring the time evolution of a ble, Fra): Photochemistry. single Bragg reflection). However, the study of more complex structures is a must. The analysis of more than AMERICA one Bragg reflecion and the development of ultra bril- Robert Schoenlein (Berkeley, USA): femtosecond X-Rays lance sources will be required to reach this goal. Attosec- from 3rd generation synchrotron; Stephen Leone (Berke- ond X-ray pulses production is at the very beginning. ley, USA): Molecular dynamics with ultrafast XUV radia- tion; Craig W. Siders (Orlando, USA): Condensed matter Acknowledgements structural dynamics; Abraham Szöke (Livermore, USA): We grateful acknowledge prof. F. Parmigiani that sup- Enzymatic reactions in macromolecules; Richard Lee ported this work in the frame of the INFM-Commissione (Berkeley, USA): creating and probing extreme states of Luce di Sincrotrone feasibility study: “Science case for a matter with ultrafast X-rays; A. Cavalleri (La Jolla, USA): LINAC based VUV X-ray FEL”. Condensed matter structural dynamics; A.D. Reis (Ann Arbor and Berkeley, USA): Strain propagation. References [1] Nielsen J.A. and McMorrow D., Elements of modern X-ray physics. ASIA Wiley, Chichester, 2001 Mitsuru Uesaka (Tokio, Japan): Condensed matter struc- [2] Rischel C., Rousse A., Uschmann I., Nature, 390, 490-492 (1997) tural dynamics; M. Yorozu (Tsukuba, Japan): Generation [3] Dohual A., Santamaria J., Eds., and femtobiology. of femtosecond X-ray pulses by synchrotron radiation; T. World Scientific Publishing, Singapore, 2002 i Shintake and H. Matsumoto (SPring-8, Japan): (X, XUV)- [4] Nakano H., Goto Y., Lu P., et al., Appl. Phys. Lett. 75, 2350-2352 (1999) ray Free Electron Laser. [5] Schnurer M., Streli C., Wobrauschek P., et al., Phys. Rev. Lett. 85, 3392-3395 (2000) [6] Cao J., Hao Z., Park H., et al., Appl. Phys. Lett. 83, 1044-1046 (2003) Conclusions [7] Helliwell JR, Rentzepis PM, Eds., Time-Resolved Diffraction. Oxford Well established static measurement techniques based Series on Synchrotron Radiation, No. 2. Clarendon Press, New York, on X-ray interactions with matter (such as XRD, X- ray 1997. microscopy, X-ray , X-ray photo- [8] Rousse A., Rischel C., Gauthier J.C., Cr. Acad. Sci. Iv-Phys. 1: 305-315 (2000) electron spectroscopy) may be adapted to time-resolved [9] Schoenlein R.W., Chong H.H.W., Glover T.E., et al., Cr. Acad. Sci. Iv- measurements down to the femtosecond time-scale. Phys. 2, 1373-1388 (2001) However, femtosecond time-resolution has just started [10] Schoenlein R.W., Leemans W.P., Chin A.H., et al., Science 274, 236- to be overcome in XRD. 238 (1996) To date, few machines and techniques have been devel- [11] Chin A.H., Schoenlein R.W., Glover T.E., et al., Phys. Rev. Lett. 83, oped for the production and detection of femtosecond 336-339 (1999) (hard and soft) X-ray pulses: in the frame of the synchro- [12] Kashiwagi S., Washio M., Kobuki T., et al., Nucl. Instrum. Meth. A 455, 36-40 (2000) tron facilities, in the field of LPP X-rays and by design- [13] Uesaka M., Kotaki H., Nakajima K., et al., Nucl. Instrum. Meth. A ing laser driven X-ray tubes. A next generation of accel- 455, 90-98 (2000) erator-based femtosecond X-ray sources could be the [14] Yorozu M., Yang J., Okada Y., et al., Appl. Phys. B-Lasers O 74, 327- XFELs, which are specifically designed to deliver 100 331 (2002)

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[15] Plech A., Kurbitz S., Berg K.J., et al., Europhys. Lett. 61, 762-768 1. C. Rischel, A. Rousse, I. Uschmann et al., Femtosecond time-resolved (2003) X-ray diffraction from laser-heated organic films, Nature, 390, 490- [16] Wulff M., Schotte F., Naylor G., et al., Nucl. Instrum. Meth. A 398, 492 (1997) 69-84 (1997) 2. C. Rose-Petruck, R. Jimenez, T. Guo et al., Picosecond-milliangstrom [17] Larsson J., Heimann P.A., Lindenberg A.M., et al., Appl. Phys. A- lattice dynamics measured by ultrafast X-ray diffraction, Nature, 398, Mater. 66, 587-591 (1998) 310-312 (1999) [18] Bucksbaum P.H., Merlin R., Solid State Commun. 111, 535-539 (1999) 3. A.H. Chin, R.W. Schoenlein, T.E. Glover et al., Ultrafast structural dy- [19] Schroeder C.B., Pellegrini C., Reiche S., et al., Nucl. Instrum. Meth. A namics in InSb probed by time-resolved x-ray diffraction, Phys. Rev. 483, 89-93 (2002) Lett., 83, 336-339 (1999) [20] Pellegrini C., Nucl. Instrum. Meth. A 445, 124-127 (2000). 4. A. Rousse, C. Rischel, S. Fourmaux et al., Non-thermal melting in [21] Brefeld W., Faatz B., Feldhaus J., et al., Nucl. Instrum. Meth. A 483, semiconductors measured at femtosecond resolution, Nature, 410, 65- 75-79 (2002) 68 (2001) [22] The European X-Ray Laser Project XFEL, 5. R. Neutze, R. Wouts, D. van der Spoel et al., Potential for biomolecu- http://xfel.desy.de/content/e169/index_eng.html. lar imaging with femtosecond X-ray pulses, Nature, 406, 752-757 [23] Materlik G., Tschentscher T., Eds., The X-ray free electron laser. TES- (2000) LA technical design report, 2001. Available inside the “The European 6. D. Umstadter, Review of physics and applications of relativistic plas- X-Ray Laser Project XFEL” mas driven by ultra-intense lasers, Phys. Plasmas, 8, 1774-1785 Part 2 web site, http://tesla.desy.de/new_pages/TDR_CD/start.html. (2001) [24] TESLA XFEL First Stage of the X-Ray Laser Laboratory Technical 7. M. Wulff, F. Schotte, G. Naylor et al., Time-resolved structures of Design Report, 2002. Available inside the “The European X-Ray macromolecules at the ESRF: Single-pulse Laue diffraction strobo- Laser Project XFEL” scopic data collection and femtosecond flash photolysis, Nucl. In- web site, http://tesla.desy.de/new_pages/tdr_update/start.html. strum. Meth. A, 398, 69-84 (1997) [25] The FERMI@ELETTRA project, http://www.elettra.trieste.it/pro- 8. C. Reich, P. Gibbon, I. Uschmann et al., Yield optimization and time jects/index.html. structure of femtosecond laser plasma K alpha sources, Phys. Rev. [26] SPring-8 Compact SASE Source, Lett., 84, 4846-4849 (2000) http://www-xfel.spring8.or.jp/SCSS.htm. 9. A. Cavalleri, C. Toth, C.W. Siders et al., Femtosecond structural dy- [27] The World Wide Web Virtual Library: Free Electron Laser research namics in VO2 during an ultrafast solid-solid phase transition, Phys. and applications, http://sbfel3.ucsb.edu/www/vl_fel.html. Rev. Lett., 87, art. no.237401 (2000) [28] The European Round Table for Synchrotron Radiation and Free Elec- 10. A. Rousse, C. Rischel, J.C. Gauthier, Colloquium: Femtosecond x-ray tron Laser, http://www.elettra.trieste.it/roundtable/. crystallography, Rev. Mod. Phys., 73, 17-31 (2001) [29] Blome C., Sokolowski-Tinten K., Dietrich C., et al., J. PHYS. IV 11, 11. J.W. Miao, K.O. Hodgson, D. Sayre, An approach to three-dimension- 491-494 (2001) al structures of biomolecules by using single-molecule diffraction im- [30] Drescher M., Hentschel M., Kienberger R., et al., Science 291, 1923- ages, P. Natl. Acad. Sci. USA, 98, 6641-6645 (2001) 1927 (2001) 12. A. Cavalleri, C.W. Siders, F.L.H. Brown et al., Anharmonic lattice dy- [31] Kienberger R., Hentschel M., Spielmann C., et al., Appl. Phys. B- namics in germanium measured with ultrafast x-ray diffraction, Lasers O 74, S3-S9 Suppl. S (2002) Phys. Rev. Lett., 85, 586-589 (2000) [32] Lee K, Cha YH, Shin MS, et al., Phys. Rev. E 67, art. no. 026502 Part 2 13. K. Sokolowski-Tinten, C. Blome, C. Dietrich et al., Femtosecond x-ray (2003) measurement of ultrafast melting and large acoustic transients, Phys. [33] Saldin E.L., Schneidmiller E.A., Yurkov M.V., Opt. Commun. 212, Rev. Lett., 87, art. no. 225701 (2001) 377-390 (2002) 14. M. Bauer, C. Lei, K. Read et al., Direct observation of surface chem- [34] Guo T., Spielmann C., Walker B.C., Barty C.P.J., Rev. Sci. Inst., 72, 41- istry using ultrafast soft-x-ray pulses, Phys. Rev. Lett., 87, art. no. 47 (2001) 025501 (2001) [35] Egbert A., Mader B., Tkachenko B., et al., App. Phys. Lett. 81, 2328- 15. G. Tempea, M. Geissler, M. Schnurer et al., Self-phase-matched high 2330 (2002) harmonic generation, Phys. Rev. Lett., 84, 4329-4332 (2000) [36] http://siders.creol.ucf.edu/lab/Research.htm 16. M. BenNun, J.S. Cao, K.R. Wilson, Ultrafast X-ray and electron diffrac- [37] http://www.amolf.nl/research/xuv_physics/tmr_network/ tion: Theoretical considerations, J. Phys. Chem. A, 101, 8743-8761 (1997) index.html?annual_report99.html 17. T. Missalla, I. Uschmann, E. Forster et al., Monochromatic focusing of [38] http://yvette.ensta.fr/~loa/index_gb.html subpicosecond x-ray pulses in the keV range, Rev. Sci. Instrum., 70, [39] http://dbs.cordis.lu/cordis-cgi/srchidadb?ACTION=D&SES- 1288-1299 (1999) SION=123782003-5- 18. R. Neutze, J. Hajdu, Femtosecond time resolution in x-ray diffrac- 23&DOC=2&CALLER=EN_UNIFIEDSRCH&TBL=EN_PROJ&RCN tion experiments, P. Natl. Acad. Sci. USA, 94, 5651-5655 (1997) =EP_RCN:52978 or go on the website of CORDIS: 19. M.F. DeCamp, D.A. Reis, P.H. Bucksbaum et al., Coherent control of http://www.cordis.lu/en/home.html, and search FAMTO. pulsed X-ray beams, Nature, 413, 825-828 (2001) Appendix 20. T. Guo, C. Spielmann, B.C. Walker et al., Generation of hard x rays by ultrafast terawatt lasers, In the appendix it is reported the list of the scientific pa- Rev. Sci. Instrum., 72, 41-47 Part 1 (2001) pers concerned with femtosecond XRD, ordered accord- 21. J. Wark, Time-resolved X-ray diffraction, Contemp. Phys., 37, 205-218 (1996) ing the “times cited” criterion and updated to 24 March 22. Y. Fujimoto, Y. Hironaka, K.G. Nakamura et al., Spectroscopy of hard 2004. The Table 1 and the Figure 1 reported in the paper X-rays (2-15 keV) generated by focusing femtosecond laser on metal main text are based on this list. The source of the list is targets, Jpn. J. Appl. Phys. 1, 38, 6754-6756 (1999)  the ISI Web of SCIENCE . 23. M. Uesaka, T. Watanabe, T. Ueda et al., Production and utilization of

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synchronized femtosecond electron and laser single pulses, J. Nucl. 46. K. Oguri, H. Nakano, T. Nishikawa et al., Cross-correlation measure- Mater., 248, 380-385 (1997) ment of ultrashort soft x-ray pulse emitted from femtosecond laser- 24. R.C. Dudek, P.M. Weber, Ultrafast diffraction imaging of the electro- produced plasma using optical field-induced ionisation, Appl. Phys. cyclic ring-opening reaction of 1,3-cyclohexadiene, J. Phys. Chem. A, Lett., 79, 4506-4508 (2001) 105, 4167-4171 (2001) 47. D. von der Linde, K. Sokolowski-Tinten, C. Blome et al., Generation 25. R.J. Tompkins, I.P. Mercer, M. Fettweis et al., 5-20 keV laser-induced and application of ultrashort X-ray pulses, Laser Part. Beams., 19, 15- x-ray generation at 1 kHz from a liquid-jet target, Rev. Sci. Instrum., 22 (2001) 69, 3113-3117 (1998) 48. J.C. Kieffer, C.Y. Chien, F. Dorchies et al., Ultrafast laser-based ther- 26. P. Villoresi, Compensation of optical path lengths in extreme-ultravi- mal X-ray sources, CR. 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68. B.W. Adams, Time-dependent Takagi-Taupin eikonal theory of X-ray 91. C. Blome, K. Sokolowski-Tinten, C. Dietrich et al., Set-up for ultrafast diffraction in rapidly changing crystal structures, Acta Crystallogr. A, time-resolved X-ray diffraction using a femtosecond laser-plasma 60, 120-133 Part 2 (2004) keV X-ray source, J. Phys. IV, 11, 491-494 (2001) 69. K. Oguri, T. Ozaki, T. Nishikawa et al., Femtosecond-resolution mea- 92. M. Jacoby, Femtosecond X-ray diffraction, Chem. Eng. News., 75, 5-5 surement of soft-X-ray pulse duration using ultra-fast population in- (1997) crease of singly charged ions induced by optical-field ionisation, Ap- 93. R.W. Schoenlein, A.H. Chin, H.H.W. Chong, R.W. Falcone, T.E. pl. Phys. B-Lasers O, 78, 157-163 (2004) Glover, P.A. Heimann, S.L. Johnson, A.M. Lindenberg, C.V. Shank, 70. M. Hagedorn, J. Kutzner, G. Tsilimis et al., High-repetition-rate hard A.A. Zholents, M.S. Zolotorev, Ultrafast X-ray science at the ad- X-ray generation with sub-millijoule femtosecond laser pulses, Appl. vanced light source, Synchrotron Radiation News, 14, 20-27 (2001) Phys. B-Lasers O, 77, 49-57 (2003) 94. X. Lu, Y.J. Li, Y. Cang et al., Simulation study of a Ne-like Ti x-ray 71. Y. Hironaka, K.G. Nakamura, K. Kondo, Ultrafast time-resolved X- laser at 32.6 nm driven by femtosecond laser pulses, Phys. Rev. A 67, ray diffraction of shock-compressed condensed matter, New Diam. Art. No.013810 (2003) Front. C Tec., 13, 161-170 (2003) 72. K. Hatanaka, T. Miura, H. Odaka et al., Various methods for X-ray pulse generation using a femtosecond laser and their potential for time-resolved X-ray analyses, Bunseki Kagaku, 52, 373-381 (2003) 73. G. Pretzler, F. Brandl, J. Stein et al., High-intensity regime of x-ray generation from relativistic laser plasmas, Appl. Phys. Lett., 82, 3623- 3625 (2003) 74. D. von der Linde, K. Sokolowski-Tinten, X-ray diffraction experi- ments with femtosecond time resolution, J. Mod. Optic., 50, 683-694 (2003) 75. D. Boschetto, C. Rischel, I. Uschmann et al., Large-angle convergent- beam setup for femtosecond X-ray crystallography, J. Appl. Crystallo- gr., 36, 348-349 Part 2 (2003) 76. A. Plech, S. Kurbitz, K.J. Berg et al., Time-resolved X-ray diffraction on laser-excited metal nanoparticles, Europhys. Lett., 61, 762-768 (2003) 77. G.K. Shenoy, Impact of next-generation synchrotron radiation sources on materials research, Nucl. Instrum. Meth. B, 199, 1-9 (2003) 78. A. Cavalleri, C. Blome, P. Forget et al., Femtosecond X-ray studies of photoinduced structural phase transitions, Phase. Transit., 75, 769-777 Part B (2002) 79. H. Kishimura, A. Yazaki, H. Kawano et al., Picosecond structural dy- namics in photoexcited Si probed by time-resolved x-ray diffraction, J. Chem. Phys., 117, 10239-10243 (2002) 80. K. Kondo, M. Mori, T. Shiraishi, X-ray generation from fs laser heated Xe clusters, Appl. Surf. Sci., 197, 138-144 (2002) 81. Y. Okano, H. Kishimura, Y. Hironaka et al., X-ray and fast ion genera- tion from metal targets by femtosecond laser irradiation, Appl. Surf. Sci., 197, 281-284 (2002) 82. Y. Hironaka, A. Yazaki, H. Kishimura et al., Picosecond X-ray diffrac- tion from laser-irradiated crystals, Appl. Surf. Sci., 197, 289-293 (2002) 83. A. Egbert, B.N. Chichkov, C. Fallnich et al., Femtosecond laser-driven x-ray tube, Opt. Eng., 41, 2658-2667 (2002) 84. P. Coppens, I.V. Novozhilova, Introductory Lecture - Time-resolved chemistry at atomic resolution, Faraday Discuss., 122, 1-11 (2003) 85. O. Synnergren, M. Harbst, T. Missalla et al., Projecting picosecond lat- tice dynamics through x-ray topography, Appl. Phys. Lett., 80, 3727- 3729 (2002) 86. B.W. Adams, Manipulation and detection of x rays on the femtosec- ond time scale (invited), Rev. Sci. Instrum., 73, 1632-1636 Part 2 (2002) 87. A. Egbert, B. Mader, B.N. Chichkov, Novel femtosecond laser-driven X-ray source, Laser. Phys., 12, 403-408 (2002) 88. A. Rousse, C. Rischel, S. Fourmaux et al., Time-resolved femtosecond x-ray diffraction by an ultra-short pulse produced by a laser, Meas. Sci. Technol., 12, 1841-1846 (2001) 89. A. Egbert, B.N. Chichkov, A. Ostendorf, Ultrashort X-ray source dri- ven by femtosecond laser pulses, Europhys. Lett., 56, 228-233 (2001) 90. N. Uesugi, H. Nakano, T. Nishikawa et al., Efficient soft X-ray gener- ation from femtosecond-laser-produced plasma and its application to time resolved spectroscopy, J. Phys. IV, 11, 397-403 (2001)

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Paper received October 2003 MAGNETIC NANOSTRUCTURES STUDIED BY POLARISED : RECENT RESULTS AND FUTURE PROSPECTS FOR POLARISED REFLECTOMETRY AT ISIS

R.M. Dalgliesh and S. Langridge Rutherford Appleton Laboratory, Oxfordshire, OX11 0QX, United Kingdom

Recent developments in the fabrication of artificial magnetic probes such as resonant magnetic x-ray reflectometry, nanostructures have led to a new insight in magnetism in sys- XPEEM (x-ray polarised electron emission microscopy), tems which have reduced thickness (relative to the magnetic magnetic has provided enormous in- exchange length) or symmetry breaking surfaces and inter- sight into the magnetism of thin film systems. faces. The physics of such systems is of fundamental interest and has also led to significant device applications. Polarised Basic Formalism Neutron Reflectometry (PNR) provides absolute depth depen- Here we shall only present a rudimentary description of dent vector magnetometry information coupled with a struc- the underlying theory of the PNR technique. For a more tural characterisation. Moreover, in-plane magnetic structures detailed description the reader is directed towards refer- can be studied. In this article we shall review a selection of the ence 2. For wider ranging reports of the application of recent investigations using polarised neutron reflectometry at the PNR technique the reader is directed to the excellent ISIS, the resulting physical insight and the future instrumen- recent reviews [4,5]. tation and possibilities for magnetic nanostructure research. As in conventional optics we can define a scattering po- tential that the neutron experiences in a medium. For a neutron incident on such a medium the scattering poten- 1. General Introduction tial contains both a nuclear (VN) and a magnetic poten-

In recent years, the study of solid state magnetism has tial (VM) component: undergone a revolution in the area of magnetic nanos- 2πh2 tructures. This has been jointly driven by the discovery V = V + V = Nb - î • B (1) N M m of the giant magnetoresistance effect (GMR) in 1988 and n the development of advanced deposition techniques where mn is the mass of the neutron, N is the number such as sputtering and molecular beam epitaxy (MBE). It density in the medium, b is the coherent scattering is now possible to grow magnetic multilayers with atom- length, µ is the neutron magnetic moment and B is the ic-plane precision, potentially with tailor-made physical magnetic induction in the medium. Substituting this po- properties. In parallel, the transition from scientific dis- tential into the Schrödinger equation a solution may be covery to commercial exploitation has been dramatic in found that allows an exact calculation of the spin-depen- this field, a panoply of practical applications exist includ- dent reflectivity from a sample consisting of discrete lay- ing magnetic devices for data storage, many types of sen- ers. Each layer may be described, in the simplest case, by sor and, potentially, quantum computing. As will be out- a thickness, average scattering length and an absolute lined in the following discussion, polarised neutron re- vector magnetic moment. This is analogous to the case flectometry is ideally suited to the study of such systems. for optical light reflection where matrix methods also al- low the exact calculation of the reflected and transmitted a. Introductory Ideas intensities. The solution of the wave equation within It was realised that the development of Polarised Neu- these layers using a matrix approach [2] then allows the tron Reflectometry (PNR) in the 1980’s would provide an spin dependent reflectivity to be calculated for non- extremely powerful technique in the study of thin film collinear magnetic structures as a function of the mea- systems. The pioneering work of Felcher and co-workers sured wavevector transfer, QZ: [1] rapidly developed and there was an increasing reali- π sation that PNR is an experimental realisation of an ab- = 4 θ Qz sin solute in-plane vector magnetometer [2,3]. In parallel, by λ (2) combining PNR with more conventional techniques such as magnetometry (SQUID, VSM, MOKE etc.), ferromag- where θ is the angle of reflection and λ is the incident netic resonance, x-ray reflectometry and spectroscopic neutron wavelength. An analysis of the polarisation state

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of the reflected neutrons (longitudinal polarisation analysis) allows the spin flip (SF) and the non spin flip (NSF) contributions to be separated. For the typical ex- perimental geometry presented in Figure 1, the compo- nents of the in-plane magnetisation, M parallel to the quantisation axis will not change the spin state of the in- cident neutron upon reflection, whereas, components or- thogonal to this axis will give rise to SF scattering. Such an analysis then allows the determination of the in-plane mangetisation. b. The CRISP Time of Flight Reflectometer The CRISP reflectometer is a time of flight polarised neu- tron reflectometer which views a liquid Hydrogen mod- erator at a temperature of ~23K. The details of the CRISP Fig. 1. The scattering geometry typically employed in PNR measure- ments. The incident neutron beam is polarised in the ±y-direction (paral- reflectometer can be found in references 6,7. Briefly, lel to H). Components of the vector magnetisation M parallel to the neu- CRISP (See Figure 2) is a vertical scattering geometry in- tron quantisation axis will give rise to non-spin flip scattering (NSF). strument which views a neutron wavelength band of Components of M orthogonal to this produce spin flip (SF) scattering. 0.5Å-6.5Å as selected by a wavelength selecting disk chopper operating at 50Hz. Background suppression is via a Nimonic chopper. The unpolarised incident beam is may be achieved by an equivalent flipper, analyser as- polarised through reflection from an FeCoV/TiN rema- sembly. In the case of a diffusely scattered beam an nent polariser [7], with an increased lower wavelength analysing mirror assembly can be installed. Given the in- cut off of 1.2Å and the spin controlled by a non-adiabatic cident wavelength range, a typical reflectivity profile can spin flipper. A 30Oe guide field maintains the neutron be achieved in 2-3 angular settings of the reflectometer polarisation pre and post sample. Polarisation analysis (see Eqn. 2). Furthermore, the wavevector resolution is

Fig. 2. A schematic of the CRISP polarised neutron time of flight reflectometer. The neutron beam is incident from the right at an inclination of 1.5° to the horizontal

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constant in ∆Q/Q and is dominated by the incident colli- a. Exchange Coupling mation (defined by the beam defining slit geometry) and The revolutionary development in applications is the is typically of order 2-4% (∆Q/Q). Flexible sample envi- creation of devices that exploit the spin rather than the ronment equipment is available covering the field range charge of the electron. It is now well known that mag- up to 1.6T and temperatures from 2K up to 200°C. netically coupled multi-layers consisting of 3d ferromag- netic layers interleaved with non-magnetic spacers ex- 2. Specular Reflectivity hibit giant magnetoresistance (GMR) [8] for appropriate As previously described, PNR may be considered as a thicknesses of the non-magnetic spacer layer. These are technique which provides an absolute vector magnetisation the regimes in which the oscillatory interlayer coupling profile of the system under investigation. Moreover, si- has an antiferromagnetic ground state between the ferro- multaneously, the physical structure of the system is ob- magnetic layers. The oscillation in coupling with spacer tained. In the case of the specular reflection of neutrons thickness is due to the quantum interference of spin-po- (incident angle equal to the reflected angle) there is no larised wave functions[9]. The observed change in resis- momentum transfer into the plane of the sample and so tivity results from the spin dependent scattering of the information is provided on the structure (both nuclear conduction electrons which depends not only on the and magnetic) parallel to the surface normal. This is ide- magnetic moment alignment but also on the interfacial ally matched to the magnetic nanostructures discussed disorder [10]. One such device made of magnetic multi- in section 1. By way of example we shall consider three layers, called a spin valve, is already employed as a read topical areas of research. head for computer hard disks, and this has led to dra-

Fig. 3. (a) The observed magnetoresistance of the Co/Cu multilayer described in the text. The submonolayer damage has a dramatic effect on the trans- port but is not observable through characterisation techniques such as x-ray reflectometry etc. (b) The room temperature magnetisation as measured by the magneto-optic Kerr effect. (c) The polarised neutron reflectivity. The solid lines are fits to the data as visualised in panel (d).

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matic improvements in data storage densities. Arrays of the structural periodicity of the multilayer and magnetic spin valves may also be used to create magnetic random information for which the magnetic propagation vector access memory, which has the advantage of being non- is 0 i.e. ferromagnetism. At half of this wave-vector is a volatile, yet faster, higher density and lower cost than further Bragg peak which arises solely from the antifer- the current dynamic random access memory devices. romagnetic correlations between the Co layers. The Of particular interest is the magnetic coupling in GMR strong splitting of the two reflectivity curves for the two ↑↓ systems and its role in the magnitude of the observed neutron spin states ()RR, , is visible close to the critical GMR particularly in the case of in-plane disorder. Mar- edge (and at the first order Bragg peak). This is indica- rows et al. [11] observed that sub-monolayer damage of a tive of ferromagnetic coupling and a single domain state multilayer stack could significantly influence the ob- sample. To understand such a system a fully dynamical served GMR. Typical transport data for Co/Cu multilay- analysis [12] approach is employed which reproduces all er is shown in Figure 3(a,b). For the clean sample there of the features in Figure 3c and is visualised in panel (d). is a large GMR and a zero remanence magnetisation To constrain the resulting model it is important to make curve. By introducing residual gas damage, the GMR is use of complementary measurements. Conventional x- √ significantly reduced and a remanence of 2/2* MSAT is ray reflectometry is used to refine the physical structure developed, where MSAT is the saturation magnetisation. of the multilayer (fitted simultaneously with the neutron Such data is indicative of an additional biquadratic term data). By saturating the sample, the magnetic structure is in the exchange coupling giving rise to a non-collinear simplified and a measurement of the PNR can extract alignment of the Co magnetisation. The PNR data from absolute moment determinations. To obtain the resultant the gas damaged multilayer [Co(10 Å)/Cu(9Å)]25 is model it is then simply necessary to relax the in-plane shown in Figure 3c. There are several features of interest. orientation of the magnetic structure. The resulting bi- The first order Bragg peak at Q=0.33Å-1 corresponds to quadratic structure resolves the apparent contradiction

Fig. 5. (Top panel) Spin analysed polarised neutron reflectivity from the Fig. 4. (a) A MOKE loop for a naturally exchange biased system double superlattice described in the text. SF and NSF antiferromagnetic (Fe/IrMn). (b) An idealised schematic of the antiferromagnet-ferromag- correlations are clearly visible for the domain wall phase. (Lower panel) net interface. A schematic of the domain wall structure residing in the antiferromagnet.

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gain a further insight into these phenomena the ability to artificially engineer systems has been exploited in so- called double superlattices [17]. The sign of the exchange coupling can be controlled through the production of an antiferromagnetically coupled multilayer ferromagneti- cally coupled to a ferromagnetically coupled multilayer. Such a system will be a suitable model for a very smooth AF/FM interface with near perfect coupling where lay- ers of Co represent layers of atomic spins in a real sys- tem. Given the ideal nature of the interface, it is a good system in which to test models of the exchange bias. Two theories have been proposed to describe the observed exchange bias based on domain models either perpen- dicular or parallel to the interface. Malozemoff [18] pro- posed that roughness at the interface creates a random exchange field, which depending on the anisotropy in the antiferromagnet may favour the formation of per- pendicular domain walls in the AF. Alternatively, Mauri and co-workers [19] proposed that even at a smooth in- terface the bias could be generated by the formation of parallel domain walls in the antiferromagnet. The spin Fig. 6. The spin asymmetry for (a) 1500Å and (b) 3000Å Pb film. The engineered double superlattice allows this later model to Keissig fringes from the thick layer are clearly visible. The solid lines are the fits for the flux exclusion in the layers. be tested. Steadman and co-workers produced double superlattices of Co/Ru with the nominal structure

Si(001)/Ta(75Å)/[Co(35Å)/Ru(15 Å)]9Co(35Å)/Ru(15 Å) of the existence of ferromagnetism and antiferromagnet- [Co(60Å)/Ru(10 Å)]10Ta(75 Å) [20]. Such dc magnetron ic coupling [13]. The physical origin of the biquadratic sputtered systems have a low structural roughness of coupling is described by the well-known Slonczewski ~2Å. To identify the proposed domain wall model polar- coupling fluctuation model of biquadratic exchange [14] isation analysis provides valuable additional informa- where different lateral regions of the multilayer (as im- tion on the layer dependent in-plane orientation. The po- posed by the sub-monolayer damage) have positive and larised neutron reflectivity with polarisation analysis is negative exchange coupling. shown in Figure 5. Three Bragg peaks are clearly observ- able corresponding to the antiferromagnetic ordering -1 b. Exchange Bias (QAF~0.054Å ), the structural (magnetic) Bragg peak as- -1 Exchange bias results from the exchange interaction be- sociated with the ferromagnetic bock (QStruct+FM~0.091Å ) tween an antiferromagnet and a ferromagnet. The exper- and the the structural (magnetic) Bragg peak associated -1 imental manifestation is that the magnetisation loop is with the antiferromagnetic bock (QStruct+AF~0.108Å ). The no longer centred around zero magnetic field (satisfying polarisation analysis allows a separation of the parallel time reversal symmetry) but is offset from zero magnetic and orthognonal components (relative to the neutron field i.e. a uni-axial anisotropy by an amount known as quantisation axis) of the layer magnetisation. Upon the the exchange bias field, HE (see Figure 4). The effect was reduction of the applied magnetic field from saturation first observed by Meiklejohn and Bean in 1956 in a Co- the antiferromagnet exhibits a spin flop phase and then CoO granular system [15]. Despite being the method of winds in to the parallel domain wall (see Figure 5) as magnetically pinning the reference layer in technologi- predicted by Mauri well over a decade before. The re- cally important devices such as spin valves [16] the sults illustrated the requirement to have anisotropy in mechanism is not fully understood. Simple models sig- the antiferromagnet and that the domain wall is primari- nificantly overestimate the magnitude of the exchange ly confined to the antiferromagnetic superlattice. bias and do not describe the enhanced coercivity, which is experimentally observed in exchange biased systems c. Magnetism and Superconductivity or the bias’ temperature dependence. A partial explana- The interplay between magnetism and superconductivi- tion for the lack of understanding is the difficulty in ty has generated enormous interest given the mutual ex- characterising the buried interface between the antiferro- clusivity of the two phenomena. Artificial magnetic magnet and ferromagnet. In this respect, the layer de- nanostructures allow one to study in a systematic man- pendence of scattering techniques is advantageous. To ner the proximity effect between a superconductor and a

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ferromagnet. PNR is able to provide information on both tion depth [23], which are less readily accessible through the flux penetration and the magnetic structure. The co- other techniques. Furthermore, PNR has been used to existence of 3D superconductivity and magnetism has study magnetic vortices, which form in type-II supercon- recently been discovered at ISIS [21]. The superconduct- ductors [24]. The current transport in such systems, ing ordering temperature of blocks much thinner than which is crucial to technological applications (high field the coherence length is comparable to the bulk for an an- magnets, field sensors, novel spin-valves etc.), depends tiferromagnetic alignment of ferromagnetic blocks, but on the pinning of such vortices. Reducing the size of the superconductivity is suppressed when the orienta- such systems results in significantly different behaviour tion is ferromagnetic, suggesting new possibilities to to that of the bulk. By varying the film thickness of the study the interplay between these usually mutually ex- superconducting layer (for thicknesses comparable to clusive phenomena and the potential for a supercon- the penetration length) the energy benefit of forming a ducting spin valve. Until recently, the thickness of the normal vortex core against the energy loss from the sur- superconducting layer has been sufficient to suppress face flux expulsion. As PNR is sensitive to the magnetic the coherent propagation of the magnetic ordering. Re- induction, B, such flux expulsion and vortices should be cently, Deen and co-workers have studied single crystal observable. Lee and co-workers [25] have investigated Gd/La superlattices [22] in which the Gd layers couple this energy balance in thin Pb films deposited by dc ferromagnetically across the superconducting La layers. magnetron sputtering. Detailed measurements of the For conventional rare-earth superlattices the magnetic spin asymmetry: coupling is mediated by a spin density wave. The open- ()RR↑↓− ing up of a superconducting gap in the La layers does Θ= ()RR↑↓+ not effect the magnetic ordering. It is hoped that such (3) studies will provide a new insight into interaction be- tween magnetism and superconductivity. below the transition temperature (T=3K, TC~6K) give in- In the case of purely superconducting systems a knowl- formation on the spatial variation of the magnetic flux edge of the magnetic induction profile at the surface of a density within the Pb layer. The results are presented in superconductor allows one to test ideas in the Ginzburg- Figures 6,7. In the thicker sample, the analysis clearly in- Landau theory. PNR has been demonstrated to provide dicates the presence of a vortex structure. Such observa- valuable information on such parameters as the penetra- tions will allow comparison with both the theory of

Fig. 7. A schematic view of the flux density profile in the superconducting phase resulting from the previous modelling for the two film thicknesses. The vortex structure is clearly visible in the centre of the Pb film.

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rection parallel to the incident beam. A number of fea- tures that are frequently observed are illustrated in Fig- ure 8. These include the so called "Yoneda Wings", dif-

fraction peaks and streaks of intensity at constant Qz. The origins of the these types of scattering are broadly understood but the subtle nuances that enable a detailed understanding and description of any particular prob- lem are still a matter of continuing theoretical and exper- imental development [26,27]. A number of theoretical treatments of off-specular reflec- tivity from distinct types of interface exist; these include self-affine fractals, islands, pitted surfaces and capillary waves but all theses analyses are based, in general, on the use of the Distorted Born Wave Approximation (DW- BA). A description of these theoretical treatments will not be undertaken here and the reader is directed to a se- ries of detailed texts describing both the derivation and Fig. 8. A schematic reciprocal space map showing some of the common features observed in off-specular neutron reflection. experimental application of these techniques in refer- ences 28, 29, 30, 31, 32. In a number of the cases mention above the evaluation of non-analytical integrals is re- mesoscopic superconductivity and with more complicat- quired making calculation computationally expensive. ed magnetic-superconducting systems. Fortunately a number of approximations are possible [28], in particular where the scattering occurs at Q vec- 3. Offspecular scattering tors well away from the critical edge. It is clear that the Diffuse scatter observed around the specularly reflected future increasing demands will require the development beam is known as off-specular reflection or scattering. of more advanced analysis techniques. Structure in this scatter may be related to in-plane corre- In recent years off-specular scattering has been studied lations within the interface under investigation in the di- in order to increase our understanding of a number of different magnetic systems. The ever-decreasing grain sizes required to increase storage density in recording media has generated particular interest. The highest densities of today are approaching the limits of thermal stability and, as a consequence, patterned nanoparticle assemblies are being considered for data storage. Multi- layers also offer a new approach to some of the canonical problems in condensed matter research, such as the in- terplay between superconductivity and magnetism, and

Fig. 9. Reciprocal space maps of off-specular reflectivity from a disor- Fig. 10. Schematic diagrams of "Magnetic Roughness" (a) A structurally dered [Co/Cu] multilayer. (a) in remnant field of 40Oe and (b) in a satu- rough, single domain state. (b) An atomically smooth interface with a do- rating field of several kOe. main structure. (c) A system combining

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low field. This scattering may be "switched off" by ap- plying a saturating field to the sample and so must be associated with some sort of magnetic structure. Figure 10 illustrates a number of possible magnetic structures at the interfaces between layers that would result in mag- netic off-specular scattering. Langridge et al. [33] consid- ered such distributions of domains and have developed a framework within which the off-specular scattering from around a Bragg peak, such as those shown, may be fitted to extract a correlation length that characterises the magnetic domain disorder within a multilayer. For this case a systematic study of the field dependence of the scattering around the AF ordering peak revealed a large domain disorder in the Co layers close to the coercive field. As the applied field strength was increased the do- main sizes increased, the disorder in the magnetisation direction of the domains reduced as the moments aligned along the applied field direction and the antipar- allel alignment across the non-magnetic Cu spacer was reduced. The strong field dependence of the domain dis- order and size along with the changes in interlayer cou- pling reveal the close relationship between interfacial structure and the GMR effect. Takeda et al have also investigated the effect of interfa- cial roughness on the GMR effect by producing Fe/Cr multilayers within which the interfacial roughness has been systematically varied by annealing. Figure 11 (a)

shows a Qx-Qz (cf. Figure 1) map of the reflected intensi- ty from an unannealed film of [Fe(3.0nm)/Cr(1.0nm)]. -1 -1 Two Bragg peaks are visible at Qz=0.8Å and Qz=1.6Å these correspond to the antiferromagnetic ordering and Fig. 11. Reciprocal space maps of the off-specular reflectivity from an the bilayer structure. The bright streak of intensity [Fe(3.0nm)/Cr(1.0nm)] multilayer (Top panel) as deposited with no an- around the antiferromagnetic ordering peak indicates nealing (Lower panel) after 7 hours annealing at 723K. that strong magnetic roughness correlations exist be- tween the layers Figure 11 (b) shows the result of an- nealing a twin film at 723K for 6 hours. It can be seen quantum confinement within thin layers. The ability of that in addition to the scatter around the antiferromag- neutrons to probe buried interfaces and their sensitivity netic peak a streak of intensity now also appears around to magnetic structure means that they are ideally suited the structural Bragg peak indicating that the interlayer this type of problem. correlations have been enhanced. Both off-specular and In order to better understand the underlying physics be- specular data have been fitted for these samples and hind this industrial driving force, numerous groups have from these fits magnetic and structural interfacial rough- begun to investigate model multilayer systems. Figure 9 ness parameters calculated. Takeda et al have concluded shows two reciprocal space maps calculated from a time that, in this case, large in-plane correlation lengths have of flight spectrum obtained by Langridge et al. from no beneficial effect on the GMR effect within the films. such a model film. In this case the film is a Co/Cu multi- However, an understanding of the nature of the magnet- layer, figure 9 (a) shows the off-specular reflectivity at a ic interfacial roughness was not achieved in these exper- low applied field (~40Oe) and 8(b) the reflectivity at a iments and so further work investigating the spin de- saturating field of 700 Oe. The specular ridge is clearly pendence of the off-specular scattering has been under- visible in both cases, running horizontally at Qx=0.0. taken. Initial results have shown that the magnetic scat- Two Bragg peaks are visible at low applied field, one tering is dominated by the spin-flip components indicat- due to the periodic structure of the multilayer and the ing that the magnetic moments with the films are other an anti-ferromagnetic ordering peak. Diffuse scat- aligned with a significant component perpendicular to tering associated with the AF peak is also observed at the applied field.

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Patterned Multilayers the anisotropy direction. The long-term aim of this work Current lithographic techniques could potentially allow is to characterise the artificially induced periodicity and increases in storage densities up to terrabits/in2, hence the nature of the magnetic behaviour under the influ- an understanding of the effect of patterning on the mag- ence of an external field. netic structure of candidate materials on the micron scale is crucial. As part of a program to investigate the effect Magnetisation of Iron Nanoparticles. of such physical patterning on the magnetic behaviour As with the behaviour of patterned magnetic multilay- of thin films, the effect of stencilled ion irradiation on a ers an understanding of the interactions of assemblies Co/Pt multilayer has been studied by Telling et al. of magnetic nanoparticles is important when consider- [34,35]. Argon ion bombardment using a grid to mask re- ing new methods of increasing storage density. Boat- gions of a film was anticipated to produce a structure ner et al have prepared samples of single crystal iron within which the non-irradiated areas would have mag- nanoparticles embedded in a layer near the surface of netic moments rotated out of the plane of the film while an yttrium-stabilized zirconia host [36]. The particles in irradiated areas the magnetic moment would lie in the have been shown to be well separated within the zirco- plane. A striped array of magnetic moments perpendicu- nia matrix and so exchange interactions are min- lar and parallel to the neutron polarisation direction imised. The behaviour of the bulk magnetisation of the could therefore be obtained resulting in a magnetic dif- nanoparticle layer upon the application of an external fraction grating the periodicity of which could be mea- field may be modelled using only the magneto-static sured directly using off-specular reflection. Subsequent dipole interaction [37]. Initial experiments indicated application of a saturating magnetic field would destroy that a layer with a substantial magnetisation exists be-

Fig. 12. The integrated intensity around the specular reflection from a Fig. 13. Angle vs. wavelength plots of the spin dependent reflectivity patterned Co/Pt multilayer, showing diffraction peaks from a "Magnetic from an iron nonoparticle assembly embedded in a zirconia matrix. Grating" (indicated by arrows) at low and high field.

this magnetic periodicity showing that the desired long- low the surface and that the calculated model value range magnetic periodicity had been achieved. Figure 12 agreed quantitatively with the experimentally deter- shows the scattered intensity measured around the spec- mined magnetisation. Further more detailed examina- ular peak integrated across all wavelengths. Two diffrac- tion of the off-specular scattering from the sample has tion peaks either side of the specular ridge are clearly revealed magnetic components within both the off- visible at a remnant field of 40 Oe. The positions of the specular and transmitted components. Figure 13 peaks correspond well with the anticipated position cal- shows the spin dependent angle vs. wavelength maps culated from the known 13µm periodicity of the stencil taken at low incident angle for a sample in a field of grid. At a saturating field of 3kOe the peaks have clearly 4.5kOe. A difference map reveals the magnetic nature disappeared indicating that the anticipated structure of both the reflected and transmitted beams. Further with long-range magnetic order had been achieved more detailed experiments are now under way which rather than a structurally patterned film. aim to analyse both the polarised off-specular reflec- Further, more recent, measurements have investigated tivity and the small angle scattering from the nanopar- samples where ion implantation has been used to pro- ticle assembly with the aim of obtaining as much infor- duce non-magnetic regions in a film rather than rotating mation as possible.

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4. Future Instrumentation at ISIS 6. Acknowledgements The second target station at ISIS [38] will be constructed It is a pleasure to thank our colleagues for many enjoyable over the next 3 years with first beam to target expected solid state physics hours on the beamline and for their per- during 2007. The first wave of instrumentation includes mission to present recent results. In this latter respect we recommendation to build three new reflectometers, pol- particularly thank Prof. B.J.Hickey, Dr. C.H. Marrows, Dr. Ref [39], OffSpec [40] and INTER [41]. These three in- P.Steadman, Dr. M.Ali, Dr. A.T.Hindmarch, Dr. A.Potenza struments will be optimised to provide an estimated (Univ. of Leeds), Prof S.L.Lee and Dr. A.Drew (St. An- twenty times increase in performance when compared to drews Univ.) and Dr. J.P.Goff, Dr. P.Deen (Univ. of Liver- the current instruments CRISP and SURF. Such a leap in pool), Dr T.R.Charlton (Argonne National Lab./RAL), Dr. performance will be particularly beneficial for PNR mea- M.Takeda (Tohoku Univ.), Dr. N.D.Telling (Daresbury surements where the limitation of small samples sizes Lab.) and co-workers. We (and our co-workers) are grate- coupled with the intrinsic flux limited nature of the ful to the EPSRC for the provision of beamtime. source may inhibit certain parametric studies . Currently, we are further optimising the beamline design with par- References ticular attention to increased brightness and the reduc- [1] G.P. Felcher et al. Rev. Sci. Inst. 58, 609 (1987) tion of background levels. In particular, the background [2] S.J. Blundell and J.A.C. Bland Phys. Rev. B. 46, 3391 (1992) generated by fast neutrons and gamma rays that current- [3] C.F. Majkrzak, Physica B. 173, 75 (1991) ly inhibit the detailed study of off-specular reflection. [4] G.P. Felcher J. Appl. Phys. 87, 5431 (2000) Further development of detector technology will also re- [5] H. Zabel and K. Theis-Bröhl J. Phys. C. 15, 505 (2003) [6] R. Felici et al. Appl. Phys. A 45, 169 (1988) duce measurement times, reduce backgrounds and in- [7] V. Nunez et al. Physica B 241-243, 148 (1998) crease the resolution of off-specular reflection measure- [8] M.N. Baibich et al. Phys. Rev. Lett. 61, 2472 (1988) ments by making use developing microstrip and wave- [9] P. Bruno, Phys. Rev. B 52, 411 (1995) length shifting fibre technologies. [10] P. Zahn et al, Phys. Rev. Lett. 80, 4309 (1998) Two of the proposed reflectometers will be able to per- [11] C.H. Marrows et al., IEEE Trans. Magn. 33, 3673 (1997) form PNR measurements, polRef and its associated sam- [12] Analysis code can be obtained from www.isis.rl.ac.uk /LargeScale/ ple environment will be fully optimised for this purpose [13] C.H. Marrows et al. Phys. Rev. 62, 11340 (2001) [14] J.C. Slonczewski, Phys. Rev. Lett. 67, 3172 (1991) and will enable detailed control of the neutron polarisa- [15] W. H. Meiklejohn and C. P. Bean, Phys. Rev. 102, 1413 (1956) tion. OffSpec will be optimised for the study of off-specu- [16] B. Dieny et al.J. Appl. Phys. 69, 4774 (1991) lar reflectivity with a pair of high resolution 2D detectors [17] L. Lazar et al. J. Magn. Magn. Mater. 223, 299 (2001) and the implementation of the recently developed Spin [18] P. Malozemoff, Phys. Rev. B 35, 3679 (1987) Echo Resolved Grazing Incidence Scattering (SERGIS) [19] D. Mauri et al. J. Appl. Phys. 62, 3047 (1987) technique, [42, 43, 44] which will enable the study of in- [20] P. Steadman et al. Phys. Rev. Lett. 89, 077201 (2002) plane structure on the nano-scale and the investigation of [21] J.P. Goff et al. J.M.M.M. 240 592 (2002) surface crystalline diffraction. The study of nano-scale in- [22] P.P. Deen et al. submitted to Phys. Rev. Lett. plane structure will be of particular value as the size of [23] M.P. Nutley et al. Phys. Rev. B. 49 15789 (1994) [24] S-W. Han et al. Phys. Rev. B. 59 14692 (1999) correlation that may currently be investigated is limited to [25] S.L. Lee et al ISIS Annual Report 2002 above a few microns in many cases. It is envisaged that [26] S.G.E. te Velthuis et al, J. Appl. Phys., 87, 5046, (2000) such an instrument will facilitate unique experiments par- [27] H. Fritzsche et al, Langmuir, 19, 7789, (2003) ticularly in the burgeoning field of soft condensed matter. [28] S.K. Sinha et al, Phys. Rev. B, 38, 2297, (1988) [29] V. Holy et al, Phys. Rev. B, 49, 10688, (1994) 5. Conclusions [30] R. Pynn, Phys Rev B, 46, 7953, (1992) In this review, we aimed to have illustrated the state of the [31] M.K. Sanyal et al, Phys. Rev. Lett., 66, 628, (1991) art capabilities of polarised neutron reflectometry in the [32] J. Daillant and A. Gibaud, 1999, X-ray and neutron reflectivity: prin- ciples and applications (Springer-Verlag: New York) study of magnetic nano-structures as evidenced by recent [33] S. Langridge et al, Phys. Rev. Lett, 85, 4964, (2000) work on the polarised neutron reflectometer, CRISP at the [34] N. D. Telling et al, J. Appl. Phys., 93, 7420 , (2003) Rutherford Appleton Laboratory. It is clear that polarised [35] M.J. Bonder et al , J. Appl. Phys., 93, 7226 , (2003) neutron reflectometry is well placed to exploit the future [36] S. Honda et al., Appl. Phys. Lett., 77, 711, (2000) issues raised by solid state physics. The future technologi- [37] T.C. Schulthess et al,. J. Appl. Phys., 89, 7594, (2001) cal challenge is to address the complicated systems in [38] www.isis.rl.ac.uk/targetstation2/ nanotechnology (spin-electronics, patterned systems, tun- [39] www.isis.rl.ac.uk/targetstation2/instruments/POLREFweb. pdf [40] www.isis.rl.ac.uk/targetstation2/instruments/OFFSPECweb.pdf nel junctions, nano-wires etc.) which are currently being [41] www.isis.rl.ac.uk/targetstation2/instruments/INTERweb.pdf fabricated. With the worldwide experience in polarised [42] M.Th. Rekveldt, Physica B, 234–236, 1135, (1997) neutron reflectometry and the next generation of instru- [43] J. Major et al., Physica B, 336, 8, (2003) mentation the future is certainly exciting. [44] R. Pynn, et al, Rev. Sci. Inst., 73, 2948, (2002)

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Paper received March 2004 THE INFRARED BEAMLINE SISSI AT ELETTRA

S. Lupi1, A. Nucara1, L. Quaroni2, and P. Calvani1 2Sincrotrone Trieste S.C.p.A., S.S. 14 Km 163.5, in Area 1COHERENTIA-INFM and Dipartimento di Fisica Science Park, 34012 Basovizza Trieste, Italy Università di Roma La Sapienza, P.le A. Moro 2 00185 Roma, Italy

The Synchrotron Infrared Beamline SISSI (Source for Imaging circular apertures used in FT-IR have a and Spectroscopic Studies in the Infrared) under construction larger area than the linear slits used in prism or grating at ELETTRA, has been developed through a collaboration be monochromators, thus enabling higher throughput of ra- tween the COHERENTIA-INFM group of the University of diation. Moreover in prism or grating spectrometers, the Rome La Sapienza and the Sincrotrone Trieste S.C.p.A. SISSI power spectrum I(ν) is measured directly by recording will be devoted to a multidisciplinary use, ranging from Mate- the light intensity at different frequencies ν, one ν after rial Science, Chemistry, Biology, Archeometry to Industrial the other. In FT-IR, all frequencies coming from the Applications. The beamline collects the radiation emitted from source illuminate simultaneously the detector. This ac- a bending magnet in a wide solid angle (65 mrad x 25 mrad) counts for the so-called multiplex or Fellget advantage. providing a high photon flux from the far infrared to the visi- However the only available sources used in the infrared ble (1 meV-3 eV). The experimental station consists of a Bruk- through the 1980s were Globar and Mercury lamps. A er IFS-66v Michelson Interferometer associated with a Hyper- Globar source approximates a black body heated at ion 2000 infrared microscope. The high brightness of the in- about 1500-2000 K, and presents a power spectrum with frared synchrotron source coupled to the microscope will per- a maximum around 2000 cm-1. The emitted intensity mit to probe absorbing materials with a spatial resolution close quickly decreases in the far-IR for frequency ν < 500cm-1. to the diffraction limit in the infrared. The same intensity decrease is shown by the mercury source below 200 cm-1. Moreover, since the power spec- trum is emitted under a solid angle 4π, the brightness of Introduction the source is low and only a small portion of the intensi- is an extremely powerful tech- ty can be focused on a sample. Therefore experiments, nique since infrared radiation couples directly with cer- which require a high flux and/or brightness, such as for tain vibrational modes of molecules. By measuring the strongly, absorbing samples, for reflectance measure- frequency of these modes, “finger-print”of the molecules ments at grazing angle, or with High Pressure Anvil can be obtained leading to their identification in many Cell, may present a poor signal-to-noise ratio. In those materials. Moreover, infrared radiation probes the low- cases where the experiment requires a “white spectrum”, lying states of solids (phonons, quasi-electrons, polarons, the Infrared Synchrotron Radiation (IRSR) provides a etc.), the interaction between a surface and an adsorbate, high brightness source over a broad spectral range.[2] In and many other low-energy characteristics of basic im- spite of the high intensity, synchrotron infrared radiation portance for Condensed Matter Physics, Chemistry, Bio- does not degrade the sample because it does not break physics, Geology, Archaeometry and Industrial applica- any chemical bond or changes noteworthy the equilibri- tions. um temperature. Indeed experiments show that focused Infrared Spectroscopy has a long history. Infrared IRSR increases the temperature of living cells of a maxi- phononic spectra were collected already at the end of the mum of 0.5 K.[3] nineteenth century by E. Nicol and published on the first The negative effects of the low brightness of a thermal page of the first issue of Physical Review.[1] However, source are more evident in infrared microscopy, a tech- the measurements of infrared spectra, through the 1970s nique that dates back to the Seventies. So far a good sig- were based on prism or grating monochromators, which nal-to-noise ratio can be obtained with thermal sources present a low energy throughput in the infrared. A major only for samples bigger than 50x50 µm2, namely much breakthrough in infrared technology was made in the larger than the diffraction limit in the mid-infrared. In- Sixties with the introduction of the Michelson Interfer- stead that limit can be obtained by using the high bright- ometer (FT-IR) coupled to a personal computer perform- ness of the infrared synchrotron source coupled to the IR ing the . A Michelson interferometer microscope. presents several advantages in comparison with a grat- Extraction of IRSR is presently performed in most syn- ing monochromator or a prism. In particular the so- chrotron rings.[4] Surface Science using IRSR has been called Jacquinot (or throughput) advantage arises as the developed at NSLS (Brookhaven, USA) and Daresbury

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(UK). High Pressure measurements have been per- tual Brightness Ratio) has been addressed to be the most formed at UVSOR (Japan) and NSLS. IRSR Spectromi- important figure of merit of an IRSR beamline. An ABR croscopy applied to Biology, Medicine and Forensics has value of the order of 100 has to be achieved in order to been improved at ALS (Berkeley, USA) and LURE obtain the maximum spatial resolution with a confocal (France) as well as at BESSY-2 (Germany). Finally, Con- infrared microscope corresponding to the diffraction densed Matter Far-IR spectroscopy has been developed limit of about 0.78λ. at SRC (Wisconsin, USA), LURE, ANKA (Germany), Another worthwhile figure of merit for IRSR beamlines Spring-8 (Japan), DAΦNE (Frascati, Italy). This list of is the polarization degree (PD) of the radiation. It de- IRSR beamlines is far from being complete, since new pends on the emission properties of IRSR as well as on beamlines are planned or under construction on SLS the optical and geometrical characteristics of the beam- (Switzerland), ESRF (France), and at the Canadian Light line. As a general rule, the radiation collected from a Source. In this paper we present the project of the in- bending magnet under a small vertical angle is linearly frared beamline SISSI under construction at ELETTRA polarized on the plane of the particle orbit, while the off- (Trieste, Italy) and we discuss the scientific role that this axis radiation is elliptically polarized, with a PD value IR facility may play for both the Italian and the Euro- which strongly depends on both the photon energy and pean scientific community. the vertical acceptance angle. In the limit of large vertical angle (> 20 mrad) the off-axis radiation is purely circu- larly polarized. Circular polarization is of fundamental 1. Characteristics of IRSR importance in several fields of research spanning from Most of the IRSR beamlines already operating have been vibrational spectroscopy in chiral and biological systems built on second or third generation synchrotrons, where to far-IR spectroscopy in magnetic and superconductors infrared and visible radiation is extracted from a bend- materials.[7,8] Finally, an important feature of IRSR is its ing magnet in a wide solid angle. Synchrotron radiation pulsed structure. The electronic bunches at ELETTRA emitted by a bending magnet covers a broad spectral may be injected with a HWHM of about 50 ps and at a range from X-rays down to infrared and submillimeter rate of tens of ns. This bunch structure corresponds to frequencies. In this case the Schwinger equation holds photon pulses with the same time structure, which can and the emitted spectral intensity versus the energy E be used as trigger for pump-probe experiments as well consists of a featureless continuum decreasing roughly as to study nanosecond time-scale infrared response of as E5/3. However, the natural emission angle of the syn- various materials.[9] chrotron radiation, which is of the order of a few mrads in the X-rays, opens up as a function of the wave- length.[5] It increases to several tens of mrads in the in- frared, depending on the radius of the ring following the approximate law:

λ θ ().()rad =166 13/ nat ρ where λ is the wavelength and ρ is the radius of curva- λ Θ ture of the bending magnet (in the same units as ). Nat is the angle required to transmit 90% of the emitted light at the given wavelength.[6] The ELETTRA ring has a di- Θ pole radius of 5.5 m, corresponding to a value for nat of 13 mrads in the mid-infrared at 500 meV, and to 35 mrads at 25 meV in the far-infrared. Extracting radiation under such angles has been a limiting factor in the de- velopment of far-IR synchrotron sources in third genera- tion machines, since large apertures in the vertical direc- tion of the bending chambers may degrade both the sta- bility and the lifetime of the electron beam. The main characteristic of IRSR, in particular for mi- crospectroscopy applications, is the brightness. Bright- ness is defined as the photon flux per unit solid angle Fig. 1. The infrared photon flux F collected from bending magnet 9.1 of and per unit source area. The brightness gain of IRSR ELETTRA for an energy of the electron beam of 2 GeV. The flux from the with respect to a conventional infrared source (ABR, Ac- ALS source and from a Black-Body lamp are shown for comparison.

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2. The IR beamline SISSI at ELETTRA The beamline SISSI collects the infrared radiation emit- ted from the 9.1 bending magnet of ELETTRA.[10] The extraction geometry of the beamline is shown in Fig. 1. The vacuum bending chamber has been modified in or- der to obtain a large emission angle of 65*25 mrads2 which fit the natural divergence of the synchrotron radi- ation in the infrared. This vertical angle is such that the 70% of the total flux at 25 meV will be collected without any reduction in the stability and lifetime of the elec- tronic beam. The IRSR flux from the 9.1 bending as a function of fre- quency is shown in Fig. 2 for an electron beam energy of 2 GeV. In the same figure the flux radiated from the ALS beamline and from a Black-Body (BB) source are shown for comparison. Although the power intensity of IRSR drops gradually for decreasing energies according to E5/3, the intensity of a BB source decays with E more rapidly, following an exponential law. The IRSR intensi- ty becomes higher than the BB one in the far-IR, for en- ergies below 20 meV. The flux gain of IRSR in the far-IR Fig. 2. The geometry adopted for the extraction of the infrared radiation. may be used in several fields of research: for instance to The dashed area represents the horizontal collection angle subtended by the extraction mirror placed at 350 cm from the center of the particle tra- probe the conformational modes of , RNA and jectory. The dotted-dashed line corresponds to the straight section up- DNA molecules dissolved in strongly absorbing aque- stream to the bending magnet. The magnetic field profile at the entrance ous solutions. of the bending magnet is shown in the inset. Therein the trajectory delim- ited by the dotted line is that selected by the horizontal collecting angle. However, as discussed in the last section, the main fig- ure of merit for an infrared beamline is the brightness. It depends on the spatial distribution of IRSR and also on the transfer optics of the beamline. The optical layout of the length of the beamline front-end to about 150 cm. SISSI is reported in Fig. 3. Assuming the waist of the par- The first mirror (M1) placed in the chamber collects the ticle beam in the bending magnet as the origin of the infrared radiation emitted from the bending magnet. M1 longitudinal coordinate, the first vacuum chamber is presents a slit of 5 mm on the central part of the mirror placed at 350 cm: this short distance, chosen in order to body in order to reduce the thermal load. This slit trans- minimize the mirror dimensions, allows one to reduce mits the intense X-ray bending emission thus preserving

Fig.3. Layout of the SISSI infrared beamline at ELETTRA.

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the optical performance of the beamline. IRSR is deflect- The spatial distribution of IR photons obtained at F2 by ed by M1 of 90 degrees towards an ellipsoidal mirror ray tracing simulation is reported in Fig. 4a. Neither the (M2) placed at 100 cm from the previous one and mount- vertical, nor the horizontal angular distribution at F2, ed in the same vacuum chamber. M2 focuses the radia- shown in Fig.4b and Fig.4c, exceeds 0.07 rad, allowing tion at the focal point F1 placed at 1150 cm, beyond the the use of an interferometer with a large f-number. Ow- shielding wall of the synchrotron hall. The radiation is ing to the large horizontal extension of the IRSR source, then collected by the mirrors M3 and M4, which are both the image is affected by a quite small coma aberration in contained in a second vacuum chamber placed at 1450 the horizontal dimension. On the contrary, the ray distri- cm from the source, and finally focused at the entrance bution along the vertical coordinate is quite symmetric. F2 of the Michelson interferometer at 1550 cm from the The reduction of the geometrical aberrations is a crucial origin. At F2, a CVD diamond window separates the ul- point for infrared microscopy, as the symmetry and the tra high vacuum part of the beamline (which is kept at homogeneity of the photon distribution at the sample the same pressure as the synchrotron) from the low-vac- site improve the spatial resolution. uum side of the interferometer. Both the characteristics The values of brightness gain ABR can be calculated as a of the mirrors and the optical transport properties of the function of the size D of an aperture located in the sam- beamline have been studied by ray-tracing simulation. ple compartment of the interferometer. This approach The main mirror parameters are reported in Table I. simulates a real experiment and takes into account the ray distribution of IRSR at the sample site, which de- pends on aberrations, surface distortions, and misalign- ments of the beamline optical system.[10] In particular

Figure Dimension Surface parameters (cm) HxV (cm2)

Mirror 1 plane 30x15 Mirror 2 ellipsoidal 35x18 Semi major axis: 625 Semi minor axis: 424 Mirror 3 plane 15x8 Mirror 4 ellipsoidal 16x10 Semi major axis: 250 Semi minor axis: 141

Table 1

TFig. 4. Spatial (a) and horizontal (b) and vertical (c) angular ray distrib- Fig. 5. Actual brilliance ratio ABR of the SISSI beamline, calculated at ution of the IR photons at the entrance of the interferometer. several energies for a collecting angle of 65x25 mrads.

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we have considered the measured slope error for each SISSI beamline, up to the entrance of the interferometer, surface mirror. Moreover the value of ABR gives an in- has been entirely funded by Sincrotrone Trieste SCpA. sight of the sample size D for which, at a given wave- length, the use of IRSR is mandatory. In Fig. 5 the values 3. Experimental station of ABR for SISSI are reported at different energies as a The experimental station of the SISSI beamline has been function of D. As shown in the figure, the advantage of fully financed by a joint contribution of the COHEREN- the IRSR brightness becomes effective for an aperture D ≤ TIA-INFM center and of the INFM-PURS project. The 1 mm where gains of the order of 102-103 can be obtained. apparatus consists of a Bruker IFS/66v Michelson inter- For this reason we expect that the beamline will be partic- ferometer coupled to a Hyperion 2000 infrared micro- ularly suitable for microscopy with spatial resolution at scope. The spectral range from the very far-IR to the visi- the diffraction limit both in the mid and in the far-IR. ble 5 to 25000 cm-1 (1 meV-3 eV) is covered with a spec- Another important figure of merit is the polarization de- tral resolution of 0.25 cm-1 (30 µeV). Time-resolved spec- gree PD of the infrared light. Since the polarization de- tra down to nanosecond time scale can be obtained in gree depends on the vertical emission angle, a rectangu- the mid-IR using the step-scan capability of the interfer- lar slit will be placed 50 cm after the ellipsoidal mirror ometer coupled to fast electronic and detectors. The Hy- M2 in the first chamber. The slit, with a fixed aperture of perion 2000 infrared microscope associated to IRSR light, 24 × 0.3 cm2 (H×V), can be vertically displaced from the which provides a spatial resolution of a few microns, has optical axis of the beamline. The slit allows one to select been also equipped for fluorescence measurements in the off-axis radiation at a given vertical angle. In Fig. 6, the visible range. The optical setup permits a number of both the linear and circular PD at F2 are reported as a different experiments spanning from transmission to re- function of energy. As expected, the linearly polarized flectance measurements at normal and variable inci- character of IRSR is more evident in the case of a small dence angle. aperture angle, since the beamline front-end mostly col- lects on-axis radiation. Since the Michelson interferome- 4. Scientific activities ter substantially preserves the polarization properties of The unique characteristics of IRSR allows one to perform the radiation, experiments using both linear and circular a number of experiments, that are prevented when using polarization can be performed at the sample site. The a conventional thermal source. Moreover, IRSR also pro- vides a better signal-to-noise ratio and a reduction of the acquisition time in more standard experiments. As dis- cussed in the introduction, IRSR spectroscopy permits extensive applications in several fields of research. Here, we review some recent experimental results obtained with IRSR and we describe the scientific opportunities opened by the SISSI project to the Italian and European community.

4A. Solid State Physics a) High Tc Superconductors (HCTS), Colossal Magne- toresistence Manganites (CMR) and other exotic elec- tronic materials are presently extensively studied in order to investigate the role of charge localization and charge-ordering in their anomalous properties. A ma- jor contribution to this field is given by infrared spec- troscopy, which monitors the low-energy excitations of these systems, the presence of gaps in the optical conductivity σ(ω) and the formation, below a certain temperature, of charge collective modes. The σ(ω) is obtained from Kramers-Kronig transformation of the measured reflectance. An example of this “low-ener-

gy” behavior is shown by recent data in the High Tc

Superconductor Bi2Sr2CuO6 (BSCO).[11] These data lead to a new picture of the transport properties of

Fig. 6. Linear (a) and circular (b) polarization degree PD estimated as a cuprates. In the past, the optical conductivity of function of the vertical collecting angle f and for several photon energies. HCTS has been described by a single component and

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analyzed in terms of an anomalous Drude model in tive mode. In the spectroscopic studies of HCTS and which both the scattering rate Γ and the mass m of related compounds, the use of IRSR allows a com- charge carriers depend on frequency. Instead in plete coverage of the whole reflectivity spectrum from BSCO, measured down to 10 cm-1and reported in Fig. 10 to 10000 cm-1, in a single experiment performed on 7, two well separated contributions are well evident a small sample. Moreover circular polarization of in the optical conductivity. The first term is a narrow IRSR in the far infrared, which cannot be obtained Drude component with a width Γ=35 cm-1 at 30 K, in with conventional thermal sources, may open new very good agreement with transport data. The small opportunities in the spectroscopic studies of magnet- value of Γ is consistent with a metal in an extremely ic, superconducting and chiral materials. clean limit, where the carriers move in a well ordered, b) Among the various phenomena exhibited by matter nearly defect free Cu-O plane. The second component under extreme pressure conditions, one of the most is a strong band centered in the far-IR at about 100 intriguing is the occurrence of the Insulator-to-Metal cm-1, likely due to a charge collective mode. Below the transition (IMT). The development and the availabili-

critical temperature Tc both the Drude term and the ty of simple high-pressure equipment have stimulated

σ(ω) (ω) Fig. 7. The optical conductivity of a thick film of Bi2Sr2CuO6, as extracted from the reflectivity measurement R by Kramers-Kronig transforma- tion (from Ref. 11). The full triangles represent the measured DC conductivity. The open circles denote the best fit to a normal Drude term here proposed only for the 30 K curve.

collective mode lose spectral weight (SW) in favor of in the last two decades a large amount of experimen- the superconducting δ -peak mode centered at zero tal work in this field. In particular the metallization

frequency. The lost of SW indicates that the supercon- phenomena in halogen phases (liquid I2, Cl2 and Br2) ducting transition affects both terms and that the is the most interesting one, since the pressure needed charge transport is determined by a superposition of to induce the transition matches quite well the maxi- a single particle Drude contribution and of a collec- mum pressure obtainable by an Optical Anvil Cell

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(about 200 GPa).[12] In this case the effective dimen- cently performed under a collaboration between the sion of the samples (determined by the diamond sur- University of Rome La Sapienza and the Daresbury (GB) faces), is of the order of 100 microns or lower. There- IRSR beamline. This study has provided information fore infrared spectroscopy utilizing IRSR has emerged about the chemical composition of the meteorite and the as an important new tool in the panorama of High conditions under which it was formed.[14] Pressure Physics. In fact the high brilliance of IRSR re- sults in major improvements in the probing of these 4C. Surface Science small samples, and provides the maximum accessible The combination of chemical sensitivity with the IRSR signal-to-noise ratio. One may cite the determination polarization properties can be successfully applied in of the phase diagram of solid hydrogen up to 200 GPa studies of anti-corrosion and on catalytic processes oc- at Brookhaven by Hemley and collaborators. The curring at gas/solid, gas/liquid, and liquid/solid inter-

IRSR results exclude any metallization of solid H2 up faces. These studies are of interest for basic research as to those pressures.[13] well as for technology applications. The orientation of molecules at an interface is of key importance to any mi- 4B. Earth Sciences croscopic description of surface chemical reactions. The Environmental and earth sciences are research fields intermolecular forces among the adsorbed molecules where IRSR microspectroscopy can find a great number and among the molecules and the surface determine that of applications. IRSR microspectroscopy can be consid- orientation. Thus, IRSR can be a very useful technique to study the ordering and the orientation of organic and polymer molecular layers. These layers are important for the understanding of the mechanism of catalytic reac- tions, where the adsorbed molecules increase the chemi- cal and the physical stability of the materials and are of- ten used as protective layers. Since the adsorbed mole- cules are orthogonal to the surface, in order to probe their absorption the electric field of the radiation should be aligned along their molecular axis. This implies that the radiation must propagate nearly parallel to the sur- face, i.e. at grazing angle of incidence. Moreover, since the IR absorbance of the molecular modes is small, the change in the reflectance induced by a single monolayer of adsorbate is of the order of 0.1 %, and high brightness is required to obtain an adequate signal-to-noise ratio. In Fig. 8 we show the reflectance changes induced by a monolayer of Co on Cu(110) between 50 and 500 cm-1 measured at the Brookhaven IRSR beamline.[15,16] The peak at about 300 cm-1 is due to the hindered rotational mode of CO, while the minimum at about 350 cm-1 corre- sponds to the carbon-metal vibrational mode. Both the reference spectrum for the clean Cu and the adsorbate spectrum have been taken in 80 s with reproducibility of the order of 0.01%.

Fig. 8. Change of the Cu(001) single-crystal reflectivity induced by the 4D. Biology and Medical Applications adsorption of 0.5 monolayers of CO. The spectrum shown in the Figure The non-destructive character of IRSR makes it attractive has been measured at grazing incidente angle at the U4IR beamline of Brookhaven (from Ref. 16). also for biological and medical applications, since it combines a sufficiently small spot size with the possibili- ty of extracting information on chemical composition. ered as the only non-destructive tool for investigation of One of its most spectacular application, the spectrum of interaction at the bacterial-mineral interface, where the one living cell, has already been performed with IRSR small spot of infrared radiation is suitable to collect spec- microscopy.[17] In Fig. 9a we report the photograph in tra on sample areas where microorganisms are present. the visible of an elongated mouse hybridoma cell under- Another example is the study of meteoritic fragments going mitosis. The corresponding vibrational absorption collected by the Italian expedition to the Antarctic, re- spectrum is reported in Fig. 9b. Here we observe the

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amide I (1650 cm-1) and amide II (1540 cm-1) absorption of a protein. Moreover, non native b-sheets, which pre- bands which indicate the presence of proteins. The sent a transient character down to a nanosecond time amide II distribution map is shown in Fig. 9c and pre- scale, may be detected with the combination of the time- sents a symmetric distribution around the two nuclei of resolved capability of the experimental station of SISSI the cell. The absorption band at 2925 cm-1 is characteristic and the pulsed-time structure of IRSR. of the C-H methyl group corresponding to the lipid Recently the potential of vibrational microspectroscopy membrane. The distribution map of lipids (Fig. 9d) with IRSR to supplement, if not to replace, the conven- shows a peak in the absorption at the center of the cell, tional methods of histological and cytological characteri- probably indicating the formation of a new cell wall due zation in human diseases, has been reviewed.[18] In fact to mitosis. diseases usually begin with a single cell, in which both Moreover the opportunity to perform time-resolved the chemical composition and its interaction with the Fourier transform infrared experiments (TRFT) in com- surrounding tissue changes. Therefore IRSR imaging bination with a fast-mixing continous-flow microfluidic techniques coupled with fluorescence measurements device for analysis of reaction intermediates in solution, (which can be performed with the same IR microscope) will provide invaluable insight into protein structure may simultaneously provide both morphological and and dynamics. The TRFT method is complementary to chemical information about a single diseased cell and real-time NMR and circular dichroism (CD). In contrast separate its behavior from that of healthy cells. In this to NMR, which provides time-averaged information, in- area a lot of work has been done on the screening of cer- frared spectra are not affected by averaging of flexible vical cells, oral cells and bone for evidence of malignan- states. By combining information obtained from infrared cy and premalignancy.[19] studies with those from the CD method, structural ele- ments in folding intermediates can be fully described. 4.E Archaeometry The possibility of detecting native as well as not native The use of IRSR radiation offers a powerful non-destruc- structures at the same time is especially valuable in gain- tive method for the study and the conservation of cultur- ing insight into the complexity of the refolding process al heritage. In particular spectromicroscopy permits the

Fig. 9. Photograph of a living cell (a). Its transmission spectrum in the mid-IR is shown in (b). The spatial distribution in the cell of the amide II protein band at 1540 cm-1 (c) demonstrates the increased concentration around the two nuclei. The spatial distribution in the cell of the absorption band of lipids at 2925 cm-1(c), shows the increased concentration between the two nuclei, suggesting the formation of a cellular wall (from Ref.17).

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analysis of tiny samples in different forms such as pel- Acknowledgment lets, powders and solid particles, the determination of The authors wish to thank the technical staff of ELET- particle and fiber composition in archaeological findings TRA for their help in the optical and mechanical project and the analysis of complex materials such as paints, of the beamline and in the realization of the support in- pigments, ceramics and ancient papers.[20] For instance frastructure. the analysis of the interaction of inks and papers to which they are applied is of a great interest in archaeom- etry. In particular a spatial resolution ≤20 mm is much References smaller than any line made on a paper by normal pens [1] E. F. Nicol, Phys. Rev. 1, 1 (1893) and much smaller than the worst case of a single dot of [2] G.P. Williams, Nucl. Instrum. Methods A, 291, 8 (1990) ink.[21] [3] H.-Y.N. Holman, M.C. Martin, E.A. Blakely, K. Bjornstad, and W.R. In Fig. 10 we show the infrared absorption spectrum of McKinney, Biopolymers (Biospectroscopy), 57, 329 (2000) ink on a paper fiber using both synchrotron and Globar [4] See, for example, Infrared Synchrotron Radiation, edited by P. Calvani sources. The superior sensitivity and resolution of the and P. Roy (Compositori, Bologna 1998), and references therein. synchrotron based approach is well evident in the analy- [5] W.D. Duncan and G.P. Williams, Appl. Optics 22, 2914 (1983) [6] U. Schade, A. Roseler, E. H. Korte, M. Scheer, and W. B. Peatman, sis of the ink spot with a spatial resolution of about 10 Nucl. Instrum. Methods 72, 1620 (2000) µ -1 m. The spectral range between 1000 to 4000 cm con- [7] S. Kimura, UVSOR Activity Report 1997, BL6A1, p. 170 tains multiple vibrational bands of C=C, C=N, C-O, [8] S. Kimura, D. X. Li, Y. Haga, and T. Suzuki, J. Magn. Mater. 177, 3121 C=O, C-N, C-S, S-O bonds and their overtones and com- (1998) bination bands. [9] G. L. Carr, R. P. S. M. Lobo, J. LaVeigne, D. H. Rejtze, and D. B. Tan- ner, Phys. Rev. Lett. 85, 3001 (2000) [10] A. Nucara, S. Lupi, and P. Calvani, Rev. Sci. Instrum. 74, 3934 (2003) [11] S. Lupi, P. Calvani, M. Capizzi, and P. Roy, Phys. Rev. B 62, 12418 (2000) [12] U.Buontempo, E. Degiorgi, P. Postorino, M. Nardone, Phys. Rev. B 52, 874 (1995) [13] H. K. Mao, and R. J. Hemley, Rev. Mod. Phys. 66, 671 (1994); A. F. Goncharov, R. J. Hemley, H.K. Mao, and J. Shu, Phys. Rev. Lett. 80, 101 (1998) [14] A. Maras, M. Macri, P. Ballirano, P. Calvani, S. Lupi, P. Maselli, B. Ruzicka, M. J. Tobin, and M. A. Chester, Proc. of the 64h Annual Mete- oritical Society, p.5203 (2001) [15] F. M. Hoffmann, B. N. J. Persson, W. Walter, D. A. King, C. J. Hirschmugl, and G. P. Williams, Phys. Rev. Lett. 72, 1256 (1994) [16] P. Dumas, M. K. Weldon, Y.J. Chabal, amd G. P. Williams, Surf. Rev. Lett. 6, 225 (1999) [17] L. Carr, P. Dumas, C. J. Hirschmugl, and G. P. Williams, Nuovo Ci- mento D 20, 375 (1998) [18] D. L. Wetzel, and S. M. LeVine, Science 285, 1224 (1999) [19] R. K. Dukar, in Handbook of Vibrational Spectroscopy, Vol. 5, eds. J. M. Chalmers, and P. R. Griffiths, John Wiley & Sons, Ltd., U.K., 3335 (2002) [20] M. R. Derrick, D. Stulik, and J. M. Landry, Infrared Spectroscopy in Conservation Science, ed. by The Getty Conservation Institute, Los Fig. 10. Mid-IR absorption spectra of ink on a paper fiber using IRSR and a Globar source. The IRSR spectrum, measured at the ALS infrared Angeles (1995) beamline (from Ref. 21), due to the much better spatial resolution, pro- [21] 0T. J. Wilkinson, D. L. Perry, M. C. Martin, W. R. McKinney, and A. vides information about the chemical composition of ink. A. Cantu, Appl. Spectrosc. 56, 800 (2002)

5. Conclusion Source The successful use of Infrared Synchrotron Radiation as The optical parameters of the SISSI mirrors, as calculated by SHADOW a bright, pulsed, broadband source for spectroscopy and ray-tracing routine. imaging applications is evident from the number of facil- ities already operating or under commissioning in the world. On this ground the SISSI Infrared beamline, which will be assembled during the next Summer at ELETTRA, opens a new scientific perspectives for the Italian and European scientific community.

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Paper received May 2004 COMPLEX DYNAMICS IN POLYMER ELECTROLYTES

A. Triolo1, O. Russina2, M. Lanza1 and H. Grimm3 2 Hahn-Meitner Institut, Glienicker str. 100, 14109, Berlin Germany 1 Istituto per i Processi Chimico-Fisici, Consiglio Nazionale 3 Institut fuer Festkoerperforschung, Forschungszentrum delle Ricerche, via La Farina 237, 98123 Messina, Italy Juelich GmbH, D-52425 Juelich, Germany

We report high resolution Fixed Energy scans from a random as it is efficiently wrapped by frozen crystalline chains. block copolymer both in its pure and salt-doped state. There are different approaches leading to a decrease of Inelastic as well as Elastic Fixed Energy scans from the BSS the crystalline fraction in common poly-ethers. Addition at Juelich are described in terms of a wealth of re- of small ether oligomers can lead to an increasingly local laxation features, indicating the dynamic complexity of poly- disorder which prevents efficient molecular packing mer electrolytes. and, as a consequence, crystallization. Though this ap- The original approach used to quantitatively model inelastic proach is efficient in preventing crystallization, still leak- fixed energy scans and the comparison with broadband dielec- age of the low molecular weight oligomers progressively tric spectroscopy allow detecting the heterogeneous features of occurs, leading to a worsening of the device perfor- the α-process in polymer electrolytes. mances. Alternatively addition of inert fillers, such as sil- ica or alumina, has been found to significantly decrease the crystalline fraction and to efficiently improve the me- Introduction chanical properties of the PEs. Polymer electrolytes (PEs) represent a new class of com- A further approach consists in using specifically engi- posites whose performances are presently attracting a neered polyether macromolecules, whose crystalline great deal of interest: their conductivity performances fraction is very low. For example, while PEO is a semi- make them ideal for applications such as secondary bat- crystalline, polypropylene oxide (PPO) is fully amor- teries, electrochromic windows and other electrochemi- phous. Accordingly a block copolymer, where different cal devices. They are obtained by mixing of poly-ether fractions of PEO and PPO are randomly connected, can macromolecules (e.g. polyethylene oxide, PEO) and be synthesised so to be characterised by negligible crys- salts, such as Li triflate [1]. talline fraction. In this communication we will report on The ether units of the macromolecules have been shown our recent efforts in the characterization of the relaxation to wrap around the salt cation, thus performing an effi- processes in a random PEO-PPO block copolymer (pure cient solvating role, leading to salt solutions in a highly and doped with LiN(SO2CF3)2) by means of complemen- mechanically stable polymer matrix [1]. Such mechanical tary techniques such as Quasi Elastic Neutron Scattering performances and the possibility of obtaining very thin (QENS) and dielectric spectroscopy. PEs films which can efficiently chemically interact with In general the QENS technique provides information on anode and cathode electrodes make PEs extremely ap- single particle (mainly hydrogen atoms) dynamics on a pealing for a variety of applications. temporal scale ranging from 10-13 to 10-8 s on a micro- The conduction process is believed to be mainly associat- scopic length scale (of the order of a few Å) [2]. Such a ed to the cation diffusion under the influence of an exter- piece of information turns to be of fundamental impor- nal electric field [1]: in many PEs the salt is suitably cho- tance in order to address details on fast dynamics in sen to have a bulky, essentially immobile anion, whose polymers and to derive information on the geometrical contribution to conductivity becomes negligible. In these nature of the relaxation processes. As opposite to dielec- conditions, the cation diffusion is strongly related to those tric and other which may possibly cover a polymer segmental motions which, unwrapping the wider dynamic range, QENS is unique in providing in- cation, can set it free to move. Such relaxation processes formation also on the spatial scale over which the occur on a nanosecond time scale in the liquid state, process occurs. while they are drastically frozen in the crystalline state. Accordingly, in order to get an efficient cation diffusion a negligible crystalline fraction should be present in the Experimental PEs. On the other hand, when dealing with PEO a large A cross-linked poly(ethylene oxide-propylene oxide) portion of the molecules are organised in a crystalline random copolymer has been prepared as previously re- way at the normal operational conditions (i.e. below ported [3]. Both the neat sample and the one doped 60°C). This implies that the salt cation remains immobile ([O]:[Li]=20:1) with lithium bis(trifluromethanesulfonyl)

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imide, LiN(SO2CF3)2, have been studied combining a va- kind of experiments, highlighting the complementarity riety of complementary techniques. The average molecu- to the more common Elastic Fixed Energy scans [6]. lar weight of the macromonomer is ca. 8000, and the ra- Modelling of IFW-scans is based on a Cole-Davidson tio of PEO and PPO units is about 4:1. DSC measure- (CD) type susceptibility for the relaxation process [7]: ments indicate that both samples contain only a negligi- ble crystalline fraction and allow determining the glass χ’’(Q, ω)∝ωS(Q, ω)∝Im(1+iy)–b=f(y) (1) transitions for the two samples: Tg,pure=210 K and ωτ τ Tg,doped=230 K for the pure and salt-doped copolymer, re- where y(T) = (T) with (T) describing the temperature spectively. Both Elastic and Inelastic Fixed Energy scans dependence of the relaxation time and b representing the (EFES and IFES, respectively) at high energy resolution stretching of the relaxation process. For the IFW-scan y = µ ω τ ω τ (1 eV) were collected at the Backscattering Spectrome- ifw (T) and introducing ym = ifw (Tm) (Tm being the ter (BSS) in FZ-Jülich, which is based on single crystal temperature at which the IFW-scan shows a maximum), diffraction of cold neutrons with Bragg angles 2θ≅ 180° one obtains for the measured intensity for monochromatization as well as energy analysis. A ω description of the BSS may be found elsewhere [4]. Iifw = S(Q, ifw) = B + (Im – B) f(y)/f(ym) The BSS was used in the both in the elastic and inelas- tic fixed window modes (IFW). Concerning the IFW with f(y) = sin(b arctan(y))/(1 + y2)b/2 (2) mode, the chosen monochromator (Si0.9Ge0.1-111) was kept at rest but its lattice spacing being slightly differ- where B denotes the background being given by the in- ent from that of the analyzers (Si-111). This difference tensity level at low temperatures and {Tm, Im} locate the ω ω µ amounts to an energy transfer of = ifw = -14.5 eV. maximum count rate. The function f(y) has a single max-

Both the pure and salt-doped polymer samples were imum at ym which may be represented with sufficient ac- -4/5 contained in a slab aluminium cell with thickness d=0.2 curacy in terms of the stretching exponent by ym = b ω τ mm. The scattered intensity S(Q, ifw) was monitored as a for 0.2 < b <2.0. For the relaxation time (T) one may as- function of sample temperature in the range 20 K < T < sume an ansatz with 3 parameters, i.e. 450 K for the accessible range of momentum transfers Q -1 τ τ (1.02

Grapengeter et al. [5] also provide a description of this With the above approximation for ym , the stretching ex-

Fig. 1. Elastic Fixed Energy scans (EFES) collected at the BSS spectrometer on a pure sample of a crosslinked random block copolymer PEO-PPO at selected Q values. In the inset, the low temperature portion is highlighted, reporting the fit of the experimental data in terms of a model accounting for the methyl side group hopping process.

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ponent is related to those 3 parameters via the tempera- sample and the incoming neutron beam. A qualitative ture Tm for the maximum intensity by inspection of these data allows detecting three tempera- ture regimes: a) a very low regime (I) (10< T(K)< 110), ω τ ω τ ≅ -4/5 ym = ifw (Tm) = ifw 0 exp(A/(Tm-TVF)) b (4) where only a linear decreasing of the EFES can be ap- preciated; b) an intermediate regime (II) (110< T (K) < It is straightforward to extend this description of the 200) where a limited, non linear decreasing occurs and IFW-scan to more than one relaxation process, consider- c) a late regime (III) (T> 200 K) where a large decrease of ing that each process can be described in terms of Equa- the EFES occurs. In regime I no relaxation processes oc- tion 2. Dielectric spectroscopy data have also been col- cur and the linear decrease in the elastic intensity is due lected on the pure rubber over a wide temperature to the Lamb-Mossbauer effect, due to the vibrational range. AC isothermal dielectric measurements were car- motion of atoms around their equilibrium position. ried out using a fully automated frequency response Above 110 K (regime II), the clear decreasing of the analyser (Schlumberger SI 1255) combined with a EFES is related to relaxation processes occurring in the Chelsea Dielectric interface by Rheometric Scientific in glassy material (Tg=212 K). As common in similar poly- the range 10-1-105 Hz and for 150< T(K) < 350. The pure meric material, such processes can be related to highly polymer sample was disk like shaped (150 µm thick) and localised motions either of sidegroups or of small chain high purity gold was sputtered on its surfaces to form portions. Eventually, above Tg (regime III), the distinct symmetrically blocking electrodes (diameter: 30 mm). decrease of the EFES is related to the diffusive motion of The frequency positions of the tangent delta peaks (tg δ= chain portions, which relax without maintaining their ε’’/ ε’) at each temperature have been obtained, in this centre of mass fixed. preliminary communication, by fitting the experimental In Figure 2 the inelastic fixed energy scans (IFES) for the data with log-gaussian curves. same sample are reported for an energy exchange corre- sponding to λω=14. 5 µeV and different values of Q. The Results and Discussion scenario emerging from the data in Figure 2 is qualita- In Figure 1 we report the elastic fixed energy scans tively similar to the one derived from Figure 1. Follow- (EFES) collected for the neat rubber sample at different ing the interpretation of IFES provided in ref [5], it can Q values. These measurements consist in monitoring be expected that the occurrence of a relaxation process the amount of neutrons diffused by the sample without corresponds, in IFES, to the presence of a peak. We stress appreciable energy change. A non-linear decrease in this that, to our knowledge, no quantitative modelling of intensity is generally due to the occurrence of a relax- IFES has ever been reported: by using the analytical ap- ation process, leading to energy exchange between the proach described in the experimental section, we pro-

ω µ Fig. 2. Normalised Inelastic Fixed Energy scans (IFES) ( ifw=14.5 eV) collected at the BSS spectrometer on a pure sample of a crosslinked random block copolymer PEO-PPO at selected Q values (from low to high: 0.86, 1.32, 1.54, 1.74, 1.88 Å-1). The curves have been vertically shifted for clarity. The contin- uous lines correspond to the fit in terms of the model outlined in the text, accounting for a low temperature process, related to the methyl group hop- ping, and a high temperature relaxation associated to the rubber-to-liquid transition. In the inset, the two fitting contributions are reported for the case of Q=1.88 Å-1.

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dence and non-Debye shape. The high temperature por- tion of the IFES has then been modelled in terms of Eq. 2 and 3, describing the shape and temperature depen- dence of the relaxation, respectively. In the inset of Fig- ure 2, a detailed description of the two fitting compo- nents is reported. The low temperature process is characterised by a value τ for o,Methyl that shows no appreciable Q-dependence: such a feature is a consequence of the localization of the relaxation process, whose centre of mass does not dif- fuse. The activation energy for this process is 16.4 kJ/mol. This value is comparable with the correspond- ing parameters obtained for the methyl group relaxation

in glassy polymers, showing a –CH3 unit directly con- nected to the polymer backbone [6]. Fig. 3. Relaxation map for the neat crosslinked random block copolymer The information extracted from the fitting of the IFES PEO-PPO sample. The two processes observed by QENS are reported for should be directly related to its EFES counterpart (Figure the case of Q=1.88 Å-1. The red line corresponds to the methyl group hop- ping and the blue line refers to the α-process. Also the contribution to the 1). Accordingly we tried to model the low temperature α-process arising as a consequence of salt addition is reported as a dark- portion of the EFES using the fitting parameters extract- green line. Data from Dielectric spectroscopy are also reported. The three α, β and γ processes are indicated together with the temperature depen- ed from the IFES data. As mentioned above the RRDM dence of the conductivity. The continuous lines refer to Arrhenius (for β has been successfully employed to model methyl group and γ relaxations) and Vogel-Fulcher (for the α relaxation and the con- hopping processes in glassy polymers. The local envi- ductivity) laws. ronment heterogeneity experienced by the hopping unit is modelled in terms of a distribution of relaxation rates. This approach has been successfully applied to model vide the first quantitative description of IFES in terms of EFES data from a number of glassy polymers possessing a combination of Cole-Davidson relaxation processes. In a methyl sidegroup [6,9] and has been shown to be particular the continuous lines reported in figure 2 corre- equivalent to the approach involving a distribution of spond to a fit of the experimental data in terms of a com- activation energies. In this case the EFES is modelled ac- bination of two contributions arising from a localised cording to [10]: motion (low temperature contribution) and a diffusive ω π-1 Γ Γ process (high temperature one). In the present neat ma- EFES(Q) = S(Q, ~0) = Ao(Q) + 2 [1-Ao (Q)] arctg( r/ ) terial, the PPO portions possess a methyl side group and the relaxation of this unit can be proposed as responsible where Ao(Q) is the elastic incoherent structure factor for the low temperature feature in the IFES. (EISF) accounting for the geometry of the hopping In the literature, localised motions occurring in glassy process: in the case of methyl group hopping around the polymers are often described in terms of the Rotational C3v axis, we have: Rate Distribution Model [8], which accounts for the het- erogeneity of the environment experienced by the re- Ao(Q) = 1/3 [1+3jo(Q rHH)], laxing units. We choose to model such an heterogeneity in terms of a stretching of the relaxation shape, by where jo(x) is a spherical Bessel function of zero order means of the Cole-Davidson law. The temperature de- and rHH is the distance between two H atoms on the Γ pendence of the process has been described in terms of methyl group (rHH =1.78 Å). Moreover is related to the an Arrhenius law: reciprocal of the characteristic time for the relaxation and Γ r is the width of the instrumental resolution function. In τ τ Methyl = o,Methyl exp [Ea/kBT] (5) particular, one has:

Γ Γ where Ea is the activation energy for the process. Due to = o exp(- Ea/RT), the limited fraction of H atoms taking part to the Γ process, the amplitude of the peak is small and the peak o being the attempt to escape frequency and Ea the acti- itself is covered by the much stronger feature related to vation energy, which is assumed to be log-Gaussian dis- the glass-liquid transition occurring at higher tempera- tributed, according to: tures. Such a transition is generally found to be charac- _ σ π 0.5 -1 2 σ2 terised by a strongly non-Arrhenius temperature depen- g(Ea,i) = [ (2 ) ] exp[(Ea,i-Ea) /2 ],

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_ σ with Ea the average activation energy and the width of the IFES data are plotted and compared with data ob- the log-Gaussian distribution. tained using dielectric spectroscopy. Taking into proper account the fact that, below Tg, a Dielectric spectroscopy (DS) provides a detailed picture fraction, χ, of the atoms are not relaxing and can be con- of the variety of dynamic processes occurring in the ma- sidered as frozen,_ one can model the experimental EFES terial: for 150< T (K) < 330, up to four processes are high- σ χ data, using Ea, and as fitting parameters. The contin- lighted by this technique (see Figure 3): in the low tem- uous lines reported in Figure 1 correspond to the fit of perature regime, two processes can be detected which the experimental data in terms_ the model described show an Arrhenius like temperature dependence; at σ above. In particular, we obtain Ea=17.5 kJ/mol and =5 higher temperature a strongly non-Arrhenius process oc- kJ/mol. The value we derive for χ is not in agreement curs which can be interpreted as a local rubber-liquid with the number of H atoms that belong to the methyl transition and seems to behave as a trigger for the fur- groups on the PPO units: this might imply that the ther conductivity process occurring at even higher tem- probed motion is not fully attributable to the hopping peratures. A detailed description of the dielectric relax-

CH3 units, but might involve other highly localised ation map will be reported in a forthcoming communica- processes. tion. Here we aim to show the direct connection between In the higher temperature regime, the glass-liquid transi- the dynamic scenario probed by the QENS technique tion was satisfactorily modelled in terms of a VTF tem- and the one obtained using dielectric spectroscopy. In perature dependence with the following parameters: A= particular, it is interesting to note the essentially quanti-

714 K and To=165 K. The relaxation shape is found to be tative agreement between the segmental dynamics strongly non-Debye like, with b=0.61. Moreover, as can probed by QENS and the one probed by DS: when fit- be deduced from Figure 2 for this process, the character- ting the two data sets with a VTF, one obtains: AQENS=714 istic time for the high temperature relaxation shows a K, log fo,QENS=11.81, To,QENS=165 K and ADielectric=712 K, distinct Q dependence: this is a consequence of the diffu- To,Dielectric=165 K, log fo,Dielectric=11.13. sive nature of the process. Accordingly we find that This result is relevant if one considers that the QENS da- τ τ -ν o,α(Q) depends on Q following a power law: o,α(Q)~Q , ta have been obtained fitting data collected at a very with ν=1.8. high frequency (f~109.5 Hz) as compared to frequency The relaxation map for the neat polymer sample is plot- range accessible to the DS. QENS can also provide infor- ted in Figure 3. The two processes observed modelling mation on the spatial extent of the dynamics (through

ω µ Fig. 4. Comparison between the Inelastic Fixed Energy scans (IFES) ( ifw=14.5 eV) collected at the BSS spectrometer on a pure sample of a crosslinked random block copolymer PEO-PPO and on the Li-triflate-doped sample at a selected Q value(Q=1.88 Å-1). The continuous lines correspond to fit of the experimental data in terms of the models outlined in the text. In particular, two contributions are considered for the pure polymer, while a third contri- bution, accounting for the salt-induced slow α-relaxation, has been considered for the salt-doped salmple. In the inset, a comparison between the Elastic Fixed Energy scans (EFES) for the same samples is reported.

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the ν parameter) that is not accessible to DS. Conclusion Moreover QENS allows detecting the methyl group re- We have shown that a combined use of state of the art laxation dynamics that is not probed by DS. QENS and broadband dielectric spectroscopies can pro- In Figure 4 IFES and EFES (in the inset) data for both vide a useful insight into the relaxation processes occur- the neat and the salt-doped polymer are reported for a ring in polymer electrolytes. selected Q value. It can be noticed that for tempera- In particular we exploited the wealth of information ac- tures lower than about 200 K the two data sets do not cessible from IFES, providing for the first time a detailed show appreciable differences. This indicates that the quantitative description of this kind of data sets. dynamics in that frequency/temperature range is not Finally the use of IFES data allowed a qualitative as well affected by the salt addition: in view of our previous as a quantitative detection of the dynamic heterogeneity results, we can then state that the methyl group dy- that characterises the α-relaxation in PEs. namics is not influenced by the transient crosslinks in- troduced by the salt. Above about 200 K the two sam- ples start to differentiate themselves. In particular it Acknowledgements emerges that the salt doped sample is characterised by We thank Dr. Y. Aihara (Yuasa Corp., Japan) for kindly a much slower dynamics: for this sample, the relaxation providing the samples. During the experiment, we took occurs at a higher temperature than required for the advantage of the skilful technical assistance of Mr. T. neat rubber. It is difficult to extract further information Starc. A. T. also acknowledges fruitful discussions with on the slow dynamics from the EFES data. On the other Dr. V. Arrighi (Heriot-Watt University, UK). We acknowl- hand, further inspection of the IFES data can provide edge financial support from the European Community – more useful information. A qualitative inspection of the Access to Research Infrastructure action of the Improv- IFES data shows that the salt-doped samples is charac- ing Human Potential Programme (HPRI-2001-00175) - terised by a IFES spectrum that can be considered as which funded the access to the FZJ facilities. built up by the combination of two contributions: a low temperature contribution that is centred at the same temperature where the neat sample α-process occurs References and a higher temperature one. This behaviour can be [1] a) F. M. Gray, Polymer Electrolytes (Royal Society of Chemistry: interpreted considering that the salt addition leads to Cambridge, 1997); b) J. R. MacCallum; C. A. Vincent, Polymer Elec- the formation of structural and dynamical mi- trolytes Reviews (Elsevier: New York, 1987; vol. I and II); c) Applica- tions of Electroactive Polymers (B. Scrosati Ed., Chapman and Hall: crodomains, where the salt-induced transient crosslinks London, 1993) considerably slow down the segmental dynamics, that [2] J. S. Higgins and H. C. Benoit, Polymers and Neutron Scattering are embedded in a neat rubber matrix whose dynamics (Oxford University Press, Oxford, 1993) still resembles the one of the bulk pure rubber. Such a [3] K. Hayamizu, Y. Aihara, W. S. Price, J. Chem. Phys 113, 4785 (2000) behaviour was already observed on the basis of DSC [4] www.fz-juelich.de/iff/wns_bss see also B. Alefeld, T. Springer, T. [11], PCS [12] and, recently, QENS [13] techniques for Heidemann, Nucl. Sci. and Engineering 110, 84 (1992) [5] H. H. Grapengeter, B. Alefeld, R. Kosfeld, Colloid and Polymer Sci., dilute salt-in-polymer solutions. 265, 226 (1987) On the basis of this qualitative observation, we modelled [6] see e.g. B. Frick, and L. J. Fetters, Macromolecules, 27, 974 (1994) the salt-doped IFES data using a model similar to the [7] D. W. Davidson and R. H. Cole, J. Chem. Phys., 18, 1417 (1950) one used for the pure rubber, plus one additional CD [8] A. Chahid, A. Alegria, J. Colmenero, Macromolecules, 27, 3282 (non-Arrhenius) contribution accounting for the high (1994) temperature salt-induced α -relaxation. In particular we [9] e.g. a) V. Arrighi, R. Ferguson, R. E. Lechner, M. Telling, A. Triolo, assumed that the fitting parameters for the methyl group Physica B, 301, 35 (2001); b) R. Zorn, B. Frick, L. J. Fetters, J. Chem. Phys. 116, 845 (2002); c) G. Allen, J. S. Higgins, Macromolecules, 10, relaxation and the low temperature α -process are the 1006 (1977); d) R. Mukhopadhyay, A. Alegria, J. Colmenero and B. same as obtained for the pure rubber. Accordingly the Frick, Macromolecules, 31, 3985 (1998) only free fitting parameters were the VTF and CD para- [10] see e.g. V. Arrighi and J. S. Higgins, J. Chem. Soc., Faraday Trans., meters for the high temperature α-process. For the latter 93, 1605 (1997) ν [11] C. Vachon, C. Labreche, A. Vallee, S. Besner, M. Dumontand, J. process we obtained: bslow α =0.78, slow α =2.24, Eatt, slow α Prud’homme, Macromolecules 28, 5585 (1995) =705 K, To, slow α =206 K. The temperature dependence of this process is also reported in Figure 3. At present no [12] a) R. Bergman, L. Borjesson, G. Fytas L. M. Torell, J. Non-Crystalline Solids 172-174, 839 (1994); b) R. Bergman, L. M. Torell, Solid State DS data are available on this sample, but we can antici- Ionics 85, 99 (1996) pate that the detection of this process would be compli- [13] A. Triolo et al., Physica B 301, 163 (2001); b) idem, Physica A 304 308 cate as it falls in the temperature/frequency regime (2002) where DS spectra are dominated by conductivity, which masks other contributions.

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NEUTRON PHYSICS LABORATORY OF NPI Rez PARTICIPATES IN TRANSNATIONAL ACCESS IN A JOINT PROGRAMME WITH NFL STUDSVIK

Rez Neutron Physics Laboratory [email protected]). The diffractome- acquisition systems which can be (NPL) is a part of Nuclear Physics In- ter uses advantages coming from fo- used at the same time. T-NDP is stitute of the Czech Academy of Sci- cusing both in real and momentum used as a nuclear analytical tech- ences, performing neutron physics space and yields very good resolu- nique for surface studies. It utilises experiments as well as to providing tion and luminosity. It is mainly the existence of isotopes of elements experimental facilities and research used for mapping residual macros- that produce prompt monoenergetic experience for external users. Re- trains, microstrain analysis and in charged particles upon capture of search activities of NPL are concen- situ tension/compression tests of thermal neutrons. From the energy trated at the medium power 10 MW samples in a large temperatures loss spectra of emitted products the (mean power) reactor LVR-15 which range above the room value. depth distributions of light elements belongs to the Nuclear Research In- SPN-100 multipurpose diffrac- can be reconstructed. T-NDP is stitute, plc. (NRI, plc.) and it is oper- tometer equipped with a bent Si or mainly used for study of numerous ating on a commercial basis. The re- Ge single crystal monochromator problems in solid-state physics (dif- actor operates on average about 170 and 3He position sensitive detector fusion, sputtering), material science days per year with a pattern of oper- (contact [email protected] or (corrosion), electronics, optronics, ating cycles of three weeks, each fol- [email protected]). The diffractome- life sciences etc. lowed by one week for maintenance ter also uses advantages coming NAA facility for neutron activa- and instrumentation development. from focusing both in real and mo- tion analysis is dedicated to both The thermal in the core mentum space. It is mainly used for short- and long-time irradiations 13 ⋅ 2⋅ -1 is about 9x10 n cm s . macrostrain scanning, neutron performed in vertical channels of the In total, NPL operates 8 instruments topography, special tasks of high- reactor which are located at the out- installed at 5 radial horizontal beam resolution single-crystal and powder skirts of the reactor core (contact tubes (for experiments in nuclear [email protected]). For short-time diffractometry in a short Q-range physics, solid state physics and ma- irradiation (typically 0.5-3 min.) in and Bragg diffraction optics. terials research) and two vertical ir- PE-rabbits, a pneumatic system is DN-2 double-crystal diffractome- radiation channels (for neutron acti- available which connects the dry ter DN-2 is designed for the mea- vation analysis) hired at NRI, plc. vertical channel behind a Be reflector surements of small-angle neutron For details see the Web page to a measurement station outside the scattering (SANS) in a high Q-reso- www.omega.ujf.cas.cz. The follow- reactor hall. Long-time irradiation lution range. The fully asymmetric ing instruments introduced in the (several hours to several days) is car- diffraction geometry of the bent Si text are offered for joint access pro- ried out in sealed Al-cans in the wet gram with NFL Studsvik. They are analyser is employed to transfer the vertical channels located in the Be in other laboratories either over- angular distribution of the scattered reflector of the reactor core. The irra- loaded by user demands (strain dif- neutrons to the spatial distribution diated cans are transported to hot fractometers) or are rarely provided and to analyse the scattering curve cells for disassembling and further (high resolution SANS, T-NDP and by the 1-d PSD. The remote control analysis. NAA provides a highly ac- NAA). When using these instru- of the curvatures of the monochro- curate and low-level characteriza- ments a considerable emphasis is mator and analyser crystals makes tion of various materials by deter- placed on the provision of entire possible to tune the instrument reso- mining up to 40 elements. support including high quality soft- lution easily in the dQ range from The proposal procedure (see the Web ware for data analysis, preliminary 10-4 to 10-3 Å-1, according to the ex- page www.omega.ujf.cas.cz) is simi- raw data elaboration and a perma- pected size of investigated inhomo- lar to that at NFL with no fixed nent assistance of the responsible re- geneities. It is mainly used for inves- deadlines. Everlapping membership searcher. tigations of the inhomogeneities in of the referee panel will ensure con- TKSN-400 diffractometer the size range (0.05 ÷ 5) mm. sistent standars and effective use of equipped with a bent Si single crys- T-NDP thermal neutron depth the facilities. tal monochromator and 3He position profiling facility (contact sensitive detector is dedicated to de- [email protected]) consists of a large termination of internal strains in vacuum chamber, automatic target Pavol Mikula polycrystalline materials (contact holders and several different data NPI Rez, Czech Republic

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MATERIALS INVESTIGATIONS USING MUONS AT ISIS AND PSI

Europe is fortunate in having two regular neutron users, benefiting preferentially emitted in the instan- world-class muon sources which from the complementary informa- taneous direction of the muon’s spin provide European scientists with ac- tion these techniques generate in at time of decay – so that, by detect- cess to the muon technique for con- many areas. ing the positrons coming from muon densed matter investigations: ISIS, decays inside a sample, we are able located at the Rutherford Appleton to follow the behaviour of the muon Laboratory in Oxfordshire, England, The Muon Technique polarisation as a function of time af- and PSI at Villigen, Switzerland. As At both ISIS and PSI, muons are pro- ter implantation. This in turn tells us sensitive, local magnetic probes, duced by the passage of an energetic about the muons’ local magnetic en- muons are used to study atomic-lev- proton beam through a thin carbon vironment and behaviour. The tech- el structure and dynamics. The siting target. The positive muon beams nique is known as µSR, which stands of both ISIS and PSI muon sources produced are naturally 100% spin for muon spin rotation, relaxation within neutron facilities, together polarised, and this polarisation is and resonance (for an introductory with X-ray sources being available maintained as the muons are trans- review, see S.J. Blundell, Contempo- near-by, provides opportunities for ported to the sample, implanted and rary Physics, 40 (1999) 175). researchers to exploit all three tech- thermalise. Muons have a mean life- niques in their investigations. In- time of 2.2 µs after which time they deed, increasing numbers of re- decay, emitting a positron and two Applications of the Technique searchers who use muons are also neutrinos. The decay positrons are Broadly speaking, applications of the muon technique fall into two categories – those where the muon is being used as a probe of its local environment, and those where the behaviour of the muon itself is the primary interest. In the former case, muon studies include a wide vari- ety of magnetic systems, with muons being used to explore mag- netic transitions, ordering and spin dynamics, and with the technique being sensitive to very small mag- netic fields (down to 10-5 T) and ap- propriate for investigations where the magnetism is short-range, ran- dom, or dilute. In superconducting systems, as well as investigations of the atomic-level magnetism which may be found in many of these ma- terials, muons can be used to ex- plore the flux-line lattice generated when a field is applied to a type II material, and can be used to deter- mine fundamental superconducting parameters such as the penetration depth, coherence length, supercon- ducting carrier density, effective mass and pairing mechanism. Fig. 1. Contour plot and projection of the time-average muon polarisation in silver (I) oxide, Ag2O Muons are also used for investiga- as a function of applied magnetic field and temperature. From this, detailed information about the tions of ion mobility in battery cath- muon state electronic structure in this material can be deduced, informing by analogy on the states adopted by hydrogen. ode materials, charge carrier motion

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Fig. 2. The ISIS muon beamlines. Fig. 3. The DEVA muon spectrometer at ISIS, during its use for radio- frequency muon spin resonance experiments.

in conducting polymers and molec- of muon production at each. A of near surfaceregions, thin films, ular dynamics. pulsed beam facility such as ISIS is layered structures and interfaces on Muons have a mass of one ninth that very suited to studies requiring mea- a nm scale. Both facilities welcome of the proton, and in some systems it surement to long times after muon new users, and both have EC Access is useful to think of the muon as a implantation and those entailing ap- contracts providing funding for Eu- light proton isotope. Observation of plication of a pulsed stimulus to the ropean researchers under Frame- muon behaviour then enables mod- implanted muons or sample. PSI, work Programme 6 – further details els to be built up of analogous hy- where muons are produced continu- can be found from their web sites drogen behaviour. This is particular- ously, is particularly suitable for www.isis.rl.ac.uk/muons/ and ly relevant to semiconductors, where studies where the muon polarisation lmu.web.psi.ch, together with the muon studies have been invaluable changes rapidly with time after European neutron and muon portal in elucidating the charge states, lat- muon implantation. ISIS has four http://www.muon-eu.net/. tice sites and dynamics of isolated muon instruments, together with as- hydrogen, including recently-discov- sociated sample environment equip- ered shallow-donor hydrogen states ment spanning temperatures of 25 Philip King in wide band gap materials. Muons mK – 1000 K and fields of 0 – 0.45 T, ISIS Muon Facility, can also be used as proton analogues together with facilities for gas and [email protected] in proton conductors and hydrogen liquid handling and a variety of storage materials. pulsed environments (e.g. RF radia- Dierk Herlach tion, E- and B-fields, current, light). PSI Muon Facility, PSI has six instruments for tempera- [email protected]) The ISIS and PSI Muon Facilities tures 10 mK – 900 K, fields 0 – 5 T, The ISIS and PSI facilities are com- and pressures up to 14 kbar; the plementary in terms of the types of unique low-energy muon source measurements which can be per- (tunable muon energy 0.5 – 30 keV) formed owing to the different nature allows depth-resolved investigation

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ILL & ESRF CONTRIBUTION

structural biology institutes. The take place in June this year. Scientif- Common Section four partners bring together their ex- ic collaboration is also taking shape. pertise in state-of-the-art structural The PSB project advances. “Every- PSB - The Partnership for and molecular biology in order to thing is set”, said Stephen Cusack, Structural Biology Takes Shape tackle fundamental research prob- director of the EMBL Grenoble out- The PSB is a unique integrated pro- lems related to human health. station. Indeed, the ESRF and ILL gramme and resource pool in struc- More than a year after its creation Councils late in 2003 gave the green tural genomics and proteomics. It in- by the four research institutes in light for the construction and equip- cludes the ESRF, Europe’s foremost Grenoble (France) PSB is becoming ment budget for a new laboratory synchrotron X-ray source, the ILL, a reality by uniting the activities of complex located next to EMBL the world’s leading , the four partners in a joint building. premises on the international site in the Grenoble Outstation of the Euro- Planning permission for the dedi- Grenoble. The building will have pean Molecular Biology Laboratory, cated laboratory building was ob- 1800 m2 of usable surface area. Its and the IBS, one of France’s premier tained and ground breaking will construction is due to start in June 2004 and should be finished 15 months later. The laboratory complex will also host the IVMS, the molecu- lar virology institute of the Grenoble Université Joseph Fourier. The direc- tor of the ESRF, Bill Stirling, explains that “the PSB is currently one of the ESRF’s major scientific projects. We hope that the combination of skills of the four partner institutes will make the PSB a world centre for research in Structural Biology”. In the context of the PSB, the ESRF has constructed a new, state-of-the- art, X-ray beamline, which is already partly operational, and the ILL has set up a unique laboratory for the deuteration of proteins, which is al- ready available to user groups. The Partnership will also include high- throughput protein expression and crystallisation facilities as well as fa- cilities for protein characterisation.

Gemini: A new state-of-the-art beamline inaugurated at the ESRF The first end-stations of the new ID23 beamline at the ESRF is opera- tional. Associated with the PSB sci- entific programme, it is designed to achieve high-throughput measure- ments for macromolecular crystal- lography in an automatic, industri- alised and easily usable environ- Fig. 1. The new PSB building, which is being constructed ment. Modern macromolecular crys-

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allowing researches to solve struc- tific Coordination Office ([email protected]). tures from the smallest and most ex- Templates are available on the ILL citing samples. web site: (http://www.ill.fr/pages/scence/U ser/UProposals.htm). Deuteration Laboratory The deuteration, partial or full, of bi- ological molecules, proteins, nucleic FaME 38 - Facility for Materials acids, lipids, sugars, is essential to Engineering exploit fully the techniques of neu- FaME38 provides support to enable tron scattering. As part of it’s strate- European materials engineers to gy for the expansion of the life sci- make the best use of the advanced ences program in neutron scattering neutron and synchrotron X-ray sci- the ILL, in collaboration with EMBL, entific facilities at ILL-ESRF, which has set up a laboratory for the are respectively the leading Euro- deuteration of biological molecules. pean centres for research using neu- Fig. 2. Didier Nurizzo (left), scientist in charge A molecular biologist experienced in tron and synchrotron X-ray beams. on ID23-1, discusses with Martin Noble (right), head of the first team of users on this beamline, macromolecular deuteration has FaME38 supports a variety of mate- from the University of Oxford. been appointed and a well-equipped rials engineering applications. New laboratory provided. users are helped to plan, undertake tallography experiments take under Access to the deuteration laboratory and evaluate experiments, and are one hour to complete compared to will be via proposals that will be assisted with data collection, pro- an entire day or days a few years peer-reviewed by a panel of interna- cessing and analysis. Industrial ago. This turnover is expected to in- tional experts nominated by the ILL users can additionally be provided crease with the automation of the Scientific Council in collaboration with a full measurement and data beamlines being developed at the with the EMBL. Once completed, analysis service if required. For any ESRF and EMBL. By the end of 2004, proposals should be sent, as an elec- queries, contact the FaME38 team the first ID23 station will be tronic attachment, to the ILL Scien- ([email protected])! equipped with a robotic sample changer allowing users to rapidly screen and assess their projects. Protein crystal samples are becom- ing ever smaller and difficult to ma- nipulate, with today’s samples typi- cally around 50 microns in size. ID23-1 will use a high de-magnifica- tion ratio of 1:4.5 in order to obtain a small focused beam at the sample position. The first official users on the beamline came from the Univer- sity of Oxford in April with the aim of studying samples of proteins. “This beamline is a fantastic re- source, that’s why we brought our most challenging samples, of 10 mi- crons”, explains Martin Noble, head of the team. The second end-station of ID23 is under design now and is really targeting the small crystals of protein complexes expected in the future. A custom made undulator X- ray source and focusing system will generate an intense micro-focus X- ray beam of 5 to 10 microns in size Fig. 3.

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April; they assessed the applica- open to experienced simulators and Italian senators visit the ESRF-ILL tions for their scientific quality, and to experimentalists and theoreti- On Monday 8 March, the ILL and recommended projects to be sched- cians wanting to learn about simula- ESRF welcomed a delegation of Ital- uled on beamlines during the sec- tions. Scientists using X-rays (for ex- ian Senators (Commissione Cultura). ond half of 2004. ample at the neighbouring ESRF fa- The purpose of the visit was a better For information about the ESRF, cility) are also encouraged to partici- knowledge of the two large scale fa- have a look at www.esrf.fr, or call pate since, for example, the fomal- cilities of our region. The invited +33 476 88 20 00. ism for inelastic scattering is essen- senators were M. Asciutti (President tially the same as for neutrons. A of the Commission), M. Brignone, M. one day “school” will precede the Compagna, M. Favaro, M. Monti- ILL Section workshop. cone et Mrs Acciarini; they were ac- The following workshops will be or- Web site: companied by their counsellor, M. ganised at the ILL next Autumn: http://whisky.ill.fr/Events/N2M2/ Fucito. After a general presentation index.html of the two facilities, they visited the Italian CRGs at ILL (BRISP and ESRF-ILL Workshop on Engineer- IN13) and at the ESRF (GILDA and ing Applications of Neutrons and International workshop on GRAAL). They were accompanied Synchrotron Radiation (13-14 Sep- Medium Pressure Advances for all along their visit by the represen- tember) Neutron Scattering (20-23 October) tatives and instrument responsibles It is organised by the new joint ILL- The workshop will be focussed on of INFM, Istituto nazionale per laFisica ESRF Facility for Materials Engineer- the scientific and technical advances della Materia, which is the Italian In- ing - FaME38. The aim of the work- of neutron scattering at medium stitute financing the ILL (3.5%) and shop is to increase the awareness of pressures, i.e. up to 3500 MPa (35 ESRF (16%). The senators were im- the European materials science com- kbar). By allowing large sample en- pressed both by the high scientific munity to the materials characterisa- vironments such as gas or liquid level of the ILL and the ESRF and tion techniques available at the pressure cells, neutron scattering the importance of the Italian pres- large-scale neutron and synchrotron gives a very direct access to precise ence in the two facilities (22 Italians X-ray facilities. These techniques information (e.g. crystal structure at the ILL, 40 at the ESRF). After the have enormous potential for re- with light elements, magnetic order- evening buffet they had the possibil- search, diagnostic and development ing, excitations) necessary in numer- ity of meeting the Italian staff on site applications in materials science and ous scientific areas where pressure is before their departure and to con- engineering. Workgroup sessions a crucial control parameter. The gratulate them for their enthusiasm will encourage collaborations, new meeting will be inter-disciplinary, and their professionalism. projects and networks. covering the fields of Physics, Chem- Web site: istry, Materials Science, Geophysics http://www.ill.fr/FaME38/work- and Bioscience. In all these areas, the ESRF Section shop.htm use of pressure as a control parame- ter is gaining importance. In addi- Record Requests for Beam Time tion to the scientific program, the Following the User Meeting in Feb- Neutrons & Numerical Methods progress and development of new ruary, potential users submitted a (15-18 September) pressure techniques will be an im- record number of 923 applications The purpose of this workshop is portant part of the workshop. Spe- for beam time for the March 1st three-fold; to expose experimental- cial emphasis will be put on the deadline. This represents an in- ists and theoreticians to the added needs of the neutron user communi- crease of some 23% over the num- value of numerical modelling in re- ty, future developments and new ber of projects submitted in Septem- search, to assemble and assess the perspectives. ber 2003. most recent developments in neu- Web site: The distribution of proposals across tron scattering and numerical mod- http://www.ill.fr/Events/MPN/M major scientific areas during this re- elling and to consider the role of Pa4neut.html view round, compared with Septem- simulations in the future. Most con- ber 2003, is shown in the figure 3. tributions are expected in the fields Nine Review Committees of ex- of soft condensed matter, chemical News from the ILL Scientific perts in a range of scientific do- physics and materials, including Council mains met in parallel at the ESRF in magnetism. The workshop will be Overall, the subcommittees allocated

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1270 days on all instruments (there were 50 days available for allocation Instruments available Scheduling period this round). This represents 236 ac- The following instruments will be Those proposals accepted at the next cepted proposals out of 388 submit- available for the forthcoming round: round, will be scheduled during the ted. Of the 25 Italian proposals sub- FIRST TWO CYCES in 2005. You are mitted, 12 received beam time with a • powder diffractometers: D1A†, probably already aware of the fact total of 45 days, corresponding to D1B*, D2B, D20 that - due to reinforcement work of about 3.5% of the total beam time • liquids diffractometer: D4 the reactor structure - the ILL has re- available. • polarised neutron diffractometers: duced the number of reactor cycles The next Scientific Council with its D3, D23* from 4.5 down to 3 cycles per year subcommittee meetings will be from • single-crystal diffractometers: D9, until 2006. 2 to 4 November 2004. D10, D15*, VIVALDI • large scale structure diffractome- ters: D19, DB21, LADI Reactor Cycles for 2005 ILL Call for Proposals • small-angle scattering: D11, D22 (provisional): The deadline for proposal submis- • reflectometers: ADAM*, D17 sion is Tuesday, 21 September 2004, • small momentum-transfer diffrac- Cycle n° 140 From 08/02/2005 midnight (European time). tometer: D16 Proposal submission is only possi- • diffuse-scattering spectrometer: To 30/03/2005 ble electronically. Electronic Pro- D7 Cycle n° 141 From 12/04/2005 posal Submission (EPS) is possible • three-axis spectrometers: IN1, IN3, To 01/06/2005 via our Visitors’ Club IN8, IN12*, IN14, IN20, IN22* (http://www.ill.fr, Users & Science, • time-of-flight spectrometers: IN4, Cycle n° 142 From 14/06/2005 Visitors’ Club, or directly at IN5, IN6 To 03/08/2005 http://vitraill.ill.fr/cv/ ), once you • backscattering and spin-echo spec- have logged in with your personal trometers: IN10, IN11, IN13*, username and password. IN15, IN16 The detailed guide-lines for the sub- • nuclear-physics instruments: PN1, Start-ups and shut downs are mission of a proposal at the ILL can PN3 planned at 8:30 am. be found on the ILL web site: • fundamental-physics instruments: www.ill.fr, Users & Science, User In- PF1B, PF2 formation, Proposal Submission, Standard Submission. † D1A is shared between powder dif- Giovanna Cicognani The web system will be operational fraction (D1A PWD) and strain scan- (ILL Scientific Co-ordinator) from 1 July 2004, and it will be ner applications (D1A STR). closed on 21 September, at mid- * Instruments marked with an aster- Montserrat Capellas Espuny night (European time). You will get isk are CRG instruments, where a (ESRF Press Officer) full support in case of computing smaller amount of beam time is hitches. If you have any difficulties available than on ILL-funded instru- at all, please contact our web-sup- ments, but we encourage such appli- port ( [email protected] ). cations. For any further queries, please con- tact SCO: You will find details of the instru- ments on the web, http://www.ill.fr ILL-SCO, 6 rue Jules Horowitz /index_sc.html. BP 156, F-38042 Grenoble Cedex 9 phone: +33 4 76 20 70 82, fax: +33 4 76 48 39 06 email: [email protected], http://www.ill.fr

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THE GEESTHACHT NEUTRON FACILITY GENF

Abstract With the beginning of the European framework program 6 (FP6) the Geesthacht Neutron Facility (GeNF) has been awarded an access-grant within the new NMI3 consortium further opening up its neutron in- strumentation for a wide interna- tional user community. The long- standing experience in the operation of the for user dri- ven science in combination with a strong in-house research will now be of benefit for an even larger group of scientists and industry.

Fig. 1. GKSS Research Centre Geesthacht

Main Text The Geesthacht Neutron Facility the investigation of soft matter such in four to six weeks on receipt. This (GeNF, http://genf.gkss.de) is oper- as biological structures, polymers, allows to react very fast and flexibly ated as part of the Geesthacht Neu- and colloids [another small angle on user demands and provides the tron and Synchrotron Scattering Fa- machine (SANS-1) and two reflec- possibility e.g. to thesis students to cility (GeNeSyS) by the GKSS Re- tometers (NeRO and PNR)] which gain as much training as possible. search Centre Geesthacht (Figure 1) make use of the strong scattering Furthermore, users who plan a long near Hamburg, Germany. The neu- contrast of neutrons for hydrogen term project (such as a Ph. D. thesis) tron source of GeNF is the 5 MW and dominating soft mat- can submit project proposals which swimming pool type reactor FRG-1 ter. The third focus is on the investi- cover a series of measurements over which provides an unperturbed flux gation of magnetic materials. The up to three years. Where appropri- of 1.4 × 1014 neutrons/(cm2s). With two small angle machines and both ate, users can get coordinated se- an average of 250 days of operation reflectometers (PNR, NeRO) have quential beam time on a number of per year the FRG-1 provides the polarized beam capability, opening instruments. A speciality of our facil- highest availability of all German re- them up also for research on magnet- ity is the support of not well trained search reactors. ic structures. This is a traditional or completely new users and -last The instrumentation of GeNF (Figure strength of neutrons frequently de- but not least- of industrial customers 2) has been strongly influenced by in manded by external users. which make use of nearly a third of house research focused dominantly Complementary to neutron scatter- our beamtime. The local contacts in on engineering materials science ing experiments GKSS also operates general are physicists or chemists problems, on chemical and biological facilities at the synchrotron laborato- with their own research program research as well as on magnetism. It ry HASYLAB at DESY, Hamburg. If specialised on one of the GKSS re- is complimentary to that at other re- desired access can be given to these search topics. These are mainly: search reactors since it is unique instruments where strain scanning • materials science: correlation be- worldwide in its concentration of six and texture investigations with high tween macroscopic (e.g. mechani- of the instruments on engineering energy X-rays (Liss et al. 2003) as cal, magnetic) properties of mate- materials research [one small-angle well as microtomography can be rials and parts and their structure machine (SANS-2), one ultra small performed. down to the atomic scale. Promi- angle machine (DCD), two strain Unlike at other neutron facilities ap- nent examples are residual stress scanners (ARES, FSS), a neutron radi- plications for beam time can be sub- analysis (Staron et al. 2002), quan- ography facility (GENRA-3) and one mitted continuously at GeNF titative texture analysis (Brock- texture diffractometer (TEX-2)]. The (http://genf.gkss.de, electronic sub- meier et al. 2002; Günther et al. second focus is on instruments for mission) and will be reviewed with- 2002), precipitates, clusters and

Vol. 9 n. 2 July 2004 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

45 µ &N &SR NEWS

- Garamus, V.M.: Formation of Mixed Micelles composition kinetics in Ni-Al alloys - I. Small bubbles (Staron et al. 2003; Bell- in Salt-Free Aqueous Solutions of Sodium and wide-angle neutron scattering investiga- mann et al., 2002; Nadutov et al. Dodecyl Sulfate and C12E6, Langmuir 19 tion on Ni-13 at.% Al and clusterdynamic 2002; Staron and Kampmann, (2003 ) 7214-7218. modelling. Acta Mater 48 (3) (2000) 701-712. 2000), structure of the interfaces in - Garamus, V.M., Pedersen, J.S., Maeda, H. and - Staron, P., Koçak, M. and Williams, S.: Resid- thin film systems, magnetic struc- Schurtenberger, P.: Scattering from short stiff ual stresses in friction stir welded Al sheets. tures (Zabel and Schreyer, 1998; cylindrical micelles formed by full-ionized Appl. Phys. A 74 (2002) s1161-s1162. - Staron, P., Jamnig, B., Leitner, H., Ebner, R. Schreyer et al. 2000) TDAO in NaCl/water solutions, Langmuir 19 (2003) 3656-3665. and Clemens, H.: Small-angle neutron scat- • soft matter research: biological - Günther, A., Brokmeier, H.-G., Petrovsky, E., tering analysis of the precipitation behaviour macromolecules (Willumeit et al. Siemes, H., Helming, K. and Quade, H.: Min- in a maraging steel, J. Appl. Cryst. 36 (2003) 2001a; Willumeit et al. 2001b; Bla- eral preferred orientation and magnetic prop- 415-419. ha et al. 2003), colloids / mi- erties as indicators of varying strain condi- - Willumeit, R., Forthmann, S., Beckmann, J., Diedrich, G., Ratering, R., Stuhrmann, H.B. croemulsions / nano-particles and tions in naturally deformed iron ore. Appl. and Nierhaus, K.H.: In situ structure determi- polymers (He et al. 2002; Garamus Phys. A. Material Science & Processing 74 (2002) nation of the protein L2 in the 50S subunit 1080-1082. 2003; Garamus et al. 2003). and the 70S E. coli ribosome, J. Mol. Biol. - He, L.-Z., Garamus, V., Funari, S., Malfois, In summary GeNF not only provides 305(1) (2001a) 167-177. M., Willumeit, R. and Niemeyer, B.: Compari- the users with high quality instru- - Willumeit, R., Diedrich, G., Forthmann, S., son of small angle scattering methods for the Beckmann, J., May, R.P., Stuhrmann, H.B. and mentation but also with adequate structure analysis of octyl-b-maltopyranoside Nierhaus, K.H.: Mapping proteins of the 50S scientific support on high interna- forming nanostructured aggregates, J. Phys. Subunit from E.coli ribosomes, BBA 1520 tional standards. We are looking for- Chem. B 106 (2002) 7596-7604. (2001b) 7-20. - Liss, K.D., Bartels, A., Schreyer, A. and ward to be of service for you! - Zabel, H. and Schreyer, A.: Polarized Neutron Clemens, H.: High-energy X-rays: A tool for Reflection: Revealing Spin Structures in Nanos- Reference List advanced bulk investigations in materials sci- tructured Layers, Neutron News 9 (1998) 18-23. - Bellmann, D., Clemens, H. and Banhart, J.: ence and physics, Textures and Microstructures USANS investigation of early stages of metal 35 (2003) 219-252. Regine Willumeit* foam formation. J. Appl. Phys. A, 74 (2002) - Nadutov, V.M., Garamus, V.M. and Islamov, and Andreas Schreyer** A.Kh.: Small-Angle Neutron Scattering and s1136-s1138. GKSS Research Centre Geesthacht, - Blaha, G., Wilson, D.N., Stoller, G., Fischer, G., the Mössbauer Effect in Nitrogen Austenite, Max-Planck-Str.1, 21502 Geesthacht, Willumeit, R. and Nierhaus, K.H.: Localization Physics of the Solid State 44 (2002) 686-691. of the trigger factor binding site on the riboso- - Schreyer, A., Schmitte, T., Siebrecht, R., Bödek- Germany mal 50S subunit, JMB 326 (2003) 887-897. er, P., Zabel, H., Lee, S. H., Erwin, R.W., Kwo, *Tel: +49(0)4152 871291, - Brokmeier, H.-G., Singer, W. and Kaiser, H.: J., Hong, M. and Majkrzak, C.F.: Neutron scat- email: [email protected] - a tool to optimize pro- tering on magnetic thin films: Pushing the lim- **Tel: +49(0)4152 871254, cessing of niobium tubes. Appl. Phys. A. Mate- its, J. Appl. Phys. 87 (2000) 5443-5448. email: [email protected] rial Science & Processing 74 (2002) 1704-1706. - Staron, P. and Kampmann, R.: Early-stage de-

Fig. 2. Instrumentation at GeNF. The neutron source (CNS) feeds about half of the experiments with cold neutrons.

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MEETING AND REPORTS

Giornate Didattiche “Dinamica dei sistemi molecolari complessi” e Congresso Annuale 2004 5-7 e 8-9 Luglio 2004 Le Giornate Didattiche della SISN (Società Italiana di Spettroscopia Neutronica) sono una nuova iniziativa rivolta essenzialmente a studenti, dottorandi e borsisti interessati ad acquisire i primi Hotel Monte Conero elementi di spettroscopia neutronica con lo scopo non solo di comprenderne vantaggi e potenzialità, ma Sirolo (AN) anche di applicarla praticamente alla loro ricerca.

Programma delle Giornate Didattiche Elementi Teorici • Introduzione generale alla diffusione neutronica (Prof. F. Sacchetti, Università di Perugia) • Sorgenti e strumentazione (Dr. M. Zoppi, IFAC - CNR) • Spettroscopia vibrazionale: neutroni, Raman ed IR (Prof. S. Magazù, Università di Messina) • Diffusione anelastica coerente: neutroni, luce, raggi X (Dr. U. Bafile, IFAC-CNR) • Diffusione quasielastica e spettroscopie di rilassamento (Prof. A. Deriu, Università di Parma) • Simulazioni di dinamica molecolare: dalle molecole alle macromolecole (Dr. S. Melchionna, Università di Roma - La Sapienza)

Attività Sperimentale Italiana • Diffusione anelastica coerente: BRISP (Dr. F. Formisano, OGG - INFM) • Diffusione elastica e quasielastica: IN13 (Dr. F. Natali, OGG - INFM) • Spettroscopia vibrazionale: TOSCA (Dr. D. Colognesi, IFAC - CNR) • Spettroscopia anelastica: VESUVIO (Dr. R. Senesi, Università di Roma “Tor Vergata” e INFN)

Seminari Specialistici • Idruri complessi (Prof. A. Albinati, Università di Milano) • Dinamica di calixareni e composti “caged” (Prof. R. Caciuffo, Università di Ancona) • Relazione struttura-dinamica-funzione nelle biomolecole (Prof. R. Rolandi, Università di Genova)

Sessioni interattive • Elaborazione di dati sperimentali (ad es. trasformazioni ToF-energia, sottrazione della cella ecc.) mediante programmi interattivi (a cura del Dr. A. Paciaroni, Università di Perugia)

CONGRESSO SISN 2004 8 Luglio 9 Luglio Tre relazioni su invito (60 min.) Una relazione su invito (60 min.) Otto comunicazioni orali (30 min.) Assemblea SISN Sessione poster Premiazione dei poster

Comitato Scientifico: F. Aliotta, U. Bafile, F. Barocchi, F. Carsughi, D. Colognesi, A. Deriu, A. Paciaroni

Termine per le iscrizioni alle Giornate Didattiche e per la Presentazione di Abstract per il Congresso: 30 MAGGIO 2004

Segreteria delle Giornate Didatttiche e del Congresso: Dr. D. Fermi, Unità INFM di Parma Parco Area delle Scienze 7/A - I-43100 Parma - Tel: 0521 905197 o 905565 - Fax: 0521 906022 - e-mail: [email protected]

Con il patrocinio dell’INFM-CNR

Società Italiana di Spettroscopia Neutronica - www.sisn.it

NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 9 n. 2 July 2004

48 CALL FOR PROPOSAL

Call for proposals for Call for proposals for Neutron Sources Synchrotron Radiation Sources

BENSC ALS Deadlines for next call are: Deadlines for next call are: 15 September 2004 and 15 March 2005 15 July 2004 and 15 September 2004 (cristallografia macromolecolare), 7 July 2004 (general users) ILL Deadline for next call is: BESSY 21 September 2004 Deadlines for next call are: 15 August 2004 and 15 February 2005 ISIS Deadlines for next call are: DARESBURY 16 October 2004 and 16 April 2005 Deadlines for next call are: 31 October 2004 and 30 April 2005 LLB-ORPHEE-SACLAY Deadline for next call is: ELETTRA 1 October 2004 Deadlines for next call are: 31 August 2004 and 28 February 2005 SINQ Deadline for next call is: ESRF 15 November 2004 Deadlines for next call are: 1 September 2004 and 1 March 2005 FZ Juelich Deadline for next call is: GILDA 8 November 2004 (quota italiana) Deadlines for next call are: 1 November 2004 and 1 May 2005

HASYLAB (new projects) Deadlines for next call are: 1 September 2004 and 1 March 2005

MAX-LAB Deadline for next call is: February 2005

NSLS Deadlines for next call are: 30 September 2004, 31 January and 31 May 2005

SLS Deadlines for next call are: 15 October 2004, 15 February 2005 and 15 June 2005 (cristallografia) 15 September 2004 and 15 March 2005 (general users)

Vol. 9 n. 2 July 2004 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

49 CALENDAR

June 28 - 30, 2004 WARWICK UNIVERSITY, UK July 26 - 30, 2004 GARCHING, GERMANY

Neutron and Muon Users Meeting (NMUM 2004) with 5th International Topical Meeting on Neutron the New Perspectives in Neutron and Muon Science Radiography (IT-MNR-5) workshop (NPNMS 2004) Contact: Thomas Buecherl [email protected] Tel: +49 (0) 89 289-14328 +44 1235 446882 Fax: +49 (0) 89 289-14347 +44 1235 445147 E-mail: [email protected] Corporate Development, Directorate URL: http://www.isnr.de CCLRC Rutherford Appleton Laboratory Chilton, Didcot Oxfordshire, OX11 0QX - UK

Aug 2 - 6, 2004 DENVER, COLORADO, USA

The International Symposium on Optical Science and Technology Spie’s 49TH Annual meeting. July 11 - 16, 2004 METZ, FRANCE Advances in Computational Methods for X-Ray and 12th International Conference on Liquid and Neutron Optics (AM304) Amorphous Metals (LAM12) Colorado Convention Center Institut de Physique Telephone: +1 360/676-3290 | 1, Bd Arago - 57078 Metz Cedex 3, France Fax +1 360/647-1445 | Email: [email protected] Fax : + 33 3 87 31 58 84 or + 33 3 87 31 58 01 http://spie.org/conferences/programs/04/am/ Conference e-mail :[email protected] Contact: Manuel Sanchez del Rio Contact: Dr. Monique Calvo-Dahlborg, LSG2M CNRS- E-mail: [email protected] UMR 7584, Ecole des Mines, Parc de Saurupt, 54042 URL: http://spie.org/Conferences/Calls/04/am/ Nancy Cedex, France conferences/index.cfm?fuseaction=AM304 E-mail: [email protected] URL: http://www.mines.inpl-nancy.fr/~lam12/

Sep 1 - 4, 2004 ARCACHON, FRANCE

7th International Conference on Quasi-Elastic Neutron July 19 - 23, 2004 PRAGUE, CZECH REPUBLIC Scattering (QENS 2004) 20th General Conference of the Condensed Matter Contact: A. Desmedt and F. Guillaume Division (EPS) Fax: +33 (0) 540-008-402 URL: http://cmd.karlov.mff.cuni.cz/CMD/ E-mail: [email protected] URL: http://www.qens2004.org

NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE • Vol. 9 n. 2 July 2004

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Sep 5 - 18, 2004 GRENOBLE CEDEX, FRANCE Sep 19 - 25, 2004 USTRON-JASZOWIEC, POLAND

Workshop Neutrons and Numerical Methods 2 International School and Symposium on Physics in Organisers: M. Johnson, M. Gonzalez, D. Kearley, T. Materials Science (ISSPMS’2004) Mounir Contact: Prof. Andrzej Czachor Workshop Secretaries: A. Mader, I. Volino Tel: +48 22 7180118 Institut Laue-Langevin, B.P. 156, F-38042 Grenoble, E-mail: [email protected] France URL: http://www.ipj.gov.pl/common/ISSPMS2004/ Tel.: +33 (0)4 76.20.75.25, Fax: +33 (0)4.76.20.76.88, E-mail: [email protected] - http://www.ill.fr/Events/N2M2

Oct 20 - 23, 2004 GRENOBLE CEDEX, FRANCE

Workshop at ILL: “International Workshop on Medium Sep 13 - 14, 2004 GRENOBLE, FRANCE Pressure Advanced for Neutron Scattering” Engineering applications of neutrons and synchrotron http://www.ill.fr/Events/MPN/MPa4neut.html radiation,. Joint FaME38 - ILL - ESRF workshop FaME38 at ILL-ESRF 6, rue Jules Horowitz , BP 156 38042 Grenoble CEDEX 9-France Tel.: +33-476-20-7944 Nov 27 - Dec 2, 2005 SYDNEY, AUSTRALIA Fax.: +33-476-20-7943 International Conference on Neutron Scattering (ICNS User Centre phone: +33-476-20-7941; 2005) Email: [email protected] Contact: Brendan Kennedy E-mail: [email protected] URL: http://www.sct.gu.edu.au/icns2005/ http://www.icns2005.org/announce.html

For information on advertising rates, media packs and inserts, and Conference Announcements please contact:

Ms. Desy Catena Tel: +39 6 72594100 - Fax: +39 6 2023507 E-mail: [email protected]

Vol. 9 n. 2 July 2004 • NOTIZIARIO NEUTRONI E LUCE DI SINCROTRONE

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LUCE DI SINCROTRONE SYNCHROTRON SOURCES WWW SERVERS IN THE WORLD (http://www.esrf.fr/navigate/synchrotrons.html)

ALS Advanced Light Source CAMD Center Advanced Microstructures & Devices Berkeley Lab, 1 Cyclotron Rd, MS6R2100, Berkeley, Louisiana State University, Center for Advanced CA 94720 Microstructures & Devices, 6980 Jefferson Hwy., Baton tel: +1 510.486.7745 fax: +1 510.486.4773 Rouge, LA 70806 http://www-als.lbl.gov/ tel: (225) 578-8887 fax. (225) 578-6954 Fax Tipo: D Status: O http://www.camd.lsu.edu/ Tipo: D Status: O

ANKA Forschungszentrum Karlsruhe Institut für CHESS Cornell High Energy Synchr. Radiation Source Synchrotronstrahlung Hermann-von-Helmholtz-Platz 1 Wilson Lab., Cornell University Ithaca, NY 14853, USA 76344 Eggenstein-Leopoldshafen, Germany tel: +1 607 255 7163 fax: +1 607 255 9001 tel: +49 (0)7247 / 82-6071 fax: +49-(0)7247 / 82-6172 http://www.tn.cornell.edu/ http://hikwww1.fzk.de/iss/ Tipo: PD Status: O

APS Advanced Photon Source CLS Bldg 360, Argonne Nat. Lab. 9700 S. Cass Avenue, Canadian Light Source, University of Saskatchewan, 101 Argonne, Il 60439, USA Perimeter Road, Saskatoon, SK., Canada. S7N 0X4 tel:+1 708 252 5089 fax: +1 708 252 3222 http://www.cls.usask.ca/ http://epics.aps.anl.gov/welcome.html Tipo:D status:C Tipo: D Status: C

DAFNE ASTRID INFN Laboratori Nazionali di Frascati, P.O. Box 13, ISA, Univ. of Aarhus, Ny Munkegade, DK-8000 Aarhus, I-00044 Frascati (Rome), Italy Denmark tel: +39 6 9403 1 fax: +39 6 9403304 tel: +45 61 28899 fax: +45 61 20740 http://www.lnf.infn.it/ http://www.aau.dk/uk/nat/isa Tipo:P Status: C Tipo: PD Status: O

DELTA BESSY Berliner Elektronen-speicherring Gessell.für Universität Dortmund,Emil Figge Str 74b, Synchrotron-strahlung mbH 44221 Dortmund, Germany BESSY GmbH, Albert-Einstein-Str.15, 12489 Berlin, tel: +49 231 7555383 fax: +49 231 7555398 Germany, http://prian.physik.uni-dortmund.de/ tel +49 (0)30 6392-2999 fax +49 (0)30 6392-2990 Tipo: P Status: C http://www.bessy.de Tipo: D Status: O DIAMOND Diamond Light Source Ltd, Rutherford Appleton BSRL Beijing Synchrotron Radiation Lab. Laboratory, Chilton, Oxon OX11 0QX Inst. of High Energy Physics, 19 Yucuan Rd.PO Box 918, http://www.diamond.ac.uk/ Beijing 100039, PR China Tipo:D status:C tel: +86 1 8213344 fax: +86 1 8213374 http://solar.rtd.utk.edu/~china/ins/IHEP/bsrf/bsrf.html Tipo: PD Status: O

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ELETTRA Kurchatov Sincrotrone Trieste, Padriciano 99, 34012 Trieste, Italy Kurchatov Inst. of Atomic Energy, SR Center, tel: +39 40 37581 fax: +39 40 226338 Kurchatov Square, Moscow 123182, Russia http://www.elettra.trieste.it tel: +7 95 1964546 Tipo: D Status: O Tipo: D Status: O/C

ELSA Electron Stretcher and Accelerator LNLS Laboratorio Nacional Luz Sincrotron Nußalle 12, D-5300 Bonn-1, Germany CP 6192, 13081 Campinas, SP Brazil tel:+49 288 732796 fax: +49 288 737869 tel.: (+55) 0xx19 3287.4520 fax: (+55) 0xx19 3287.4632 http://elsar1.physik.uni-bonn.de/elsahome.html http://www.lnls.br/ Tipo: PD Status: O Tipo: D Status: C

ESRF European Synchrotron Radiation Lab. LURE BP 220, F-38043 Grenoble, France Bât 209-D, 91405 Orsay ,France tel: +33 476 882000 fax: +33 476 882020 tel: +33 1 64468014; fax: +33 1 64464148 http://www.esrf.fr/ http://www.lure.u-psud.fr Tipo: D Status: O Tipo: D Status: O

EUTERPE MAX-Lab Cyclotron Lab.,Eindhoven Univ. of Technol, P.O.Box 513, Box 118, University of Lund, S-22100 Lund, Sweden 5600 MB Eindhoven, The Netherlands tel: +46 46 109697 fax: +46 46 104710 tel: +31 40 474048 fax: +31 40 438060 http://www.maxlab.lu.se/ Tipo: PD Status: C Tipo: D Status: O

HASYLAB NSLS National Synchrotron Light Source Notkestrasse 85, D-2000, Hamburg 52, Germany Bldg. 725, Brookhaven Nat. Lab., Upton, NY 11973, USA tel: +49 40 89982304 fax: +49 40 89982787 tel: +1 516 282 2297 fax: +1 516 282 4745 http://www-hasylab.desy.de/ http://www.nsls.bnl.gov/ Tipo: D Status: O Tipo: D Status: O

INDUS NSRL National Synchrotron Radiation Lab. Center for Advanced Technology, Rajendra Nagar, USTC, Hefei, Anhui 230029, PR China Indore 452012, India tel +86-551-5132231,3602034 fax +86-551-5141078 tel: +91 731 64626 http://www.nsrl.ustc.edu.cn/en/enhome.html http://www.ee.ualberta.ca/~naik/accind1.html Tipo: D Status: O Tipo: D Status: C

Pohang KEK Photon Factory Pohang Inst. for Science & Technol., P.O. Box 125 Nat. Lab. for High Energy Physics, 1-1, Oho, Pohang, Korea 790600 Tsukuba-shi Ibaraki-ken, 305 Japan tel: +82 562 792696 fax: +82 562 794499 tel: +81 298 641171 fax: +81 298 642801 http://pal.postech.ac.kr/english.html http://www.kek.jp/ Tipo: D Status: C Tipo: D Status: O

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Siberian SR Center SSRL Stanford SR Laboratory Lavrentyev Ave 11, 630090 Novosibirsk, Russia 2575 Sand Hill Road, Menlo Park, California, 94025, tel: +7 383 2 356031 fax: +7 383 2 352163 USA http://ssrc.inp.nsk.su/english/load.pl?right=general.html tel: +1 650-926-4000 fax: +1 650-926-3600 Tipo: D Status: O http://www-ssrl.slac.stanford.edu/welcome.html Tipo: D Status: O

SLS Swiss Light Source, Paul Scherrer Institut, CH-5232 SRS Daresbury SR Source Villigen PSI SERC, Daresbury Lab, Warrington WA4 4AD, U.K. http://sls.web.psi.ch/view.php/about/index.html tel: +44 925 603000 fax: +44 925 603174 Tipo: D Status: O E-mail: [email protected] http://www.dl.ac.uk/home.html Tipo: D Status: O SPring-8 2-28-8 Hon-komagome, Bunkyo-ku ,Tokyo 113, Japan tel: +81 03 9411140 fax: +81 03 9413169 SURF III http://www.spring8.or.jp/top.html B119, NIST, Gaithersburg, MD 20859, USA Tipo: D Status: C tel: +1 301 9753726 fax: +1 301 8697628 http://physics.nist.gov/MajResFac/surf/surf.html Tipo: D Status: O SOLEIL Centre Universitaire - B.P. 34 - 91898 Orsay Cedex http://www.soleil.u-psud.fr/ TERAS ElectroTechnical Lab. Tipo: D Status:C 1-1-4 Umezono, Tsukuba Ibaraki 305, Japan tel: 81 298 54 5541 fax: 81 298 55 6608 Tipo: D Status: O SOR-RING Inst. Solid State Physics S.R. Lab, Univ. of Tokyo, 3-2-1 Midori-cho Tanashi-shi, Tokyo 188, Japan UVSOR tel: +81 424614131 ext 346 fax: +81 424615401 Inst. for Molecular ScienceMyodaiji, Okazaki 444, Japan Tipo: D Status: O tel: +81 564 526101 fax: +81 564 547079 Tipo: D Status: O

SRC Synchrotron Rad. Center Univ.of Wisconsin at Madison, 3731 Schneider DriveStoughton, WI 53589-3097 USA tel: +1 608 8737722 fax: +1 608 8737192 http://www.src.wisc.edu Tipo: D Status: O

SRRC SR Research Center 1, R&D Road VI, Hsinchu Science, Industrial Parc, D = macchina dedicata D = dedicated machine Hsinchu 30077 Taiwan, Republic of China PD = parzialmente dedicata PD = partially dedicated tel: +886 35 780281 fax: +886 35 781881 P = in parassitaggio P = parassitic http://www.srrc.gov.tw/ O = macchina funzionante O = operating machine Tipo: D Status: O C = macchina in costruzione C = machine under construction

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NEUTRONI NEUTRON SCATTERING WWW SERVERS IN THE WORLD (http://www.isis.rl.ac.uk)

Atominstitut Vienna (A) FRJ-2 Research Reactor in Jülich (D) IBR2 Fast Pulsed Reactor Dubna (RU) Facility: TRIGA MARK II Type: Dido reactor. Flux: 2 x 1014 Type: Pulsed Reactor. Type: Reactor. Thermal power 250 n/cm2/s Flux: 3 x 1016 (thermal n in core) kW. Prof. D. Richter, Address for application forms: Flux: 1.0 x 1013 n/cm2/s (Thermal); Forschungszentrums Jülich GmbH, Dr. Vadim Sikolenko, 1.7 x 1013 n/cm2/s (Fast) Institut für Festkörperforschung, Frank Laboratory of Neutron Address for information: Postfach 19 13, 52425 Jülich, Physics 1020 Wien, Stadionallee 2 Germany Joint Institute for Nuclear Research Prof. H. Rauch Tel: +49 2461161 2499; Fax: +49 141980 Dubna, Moscow Region, Tel: +43 1 58801 14111; 2461161 2610 Russia. Fax: +43 1 58801 14199 E-mail: [email protected] Tel: +7 09621 65096; Fax: +7 09621 E-mail: [email protected] http://www.kfa- 65882 http://www.ati.ac.at juelich.de/iff/Institute/ins/Brosch E-mail: [email protected] Wap: wap.ati.ac.at uere_NSE/ http://nfdfn.jinr.ru/flnph/ibr2.html

NRU Chalk River Laboratories FRG-1 Geesthacht (D) ILL Grenoble (F) The peak thermal flux 3x1014 cm-2 Type: Swimming Pool Cold Type: 58MW High Flux Reactor. sec-1 Neutron Source. Flux: 1.5 x 1015 n/cm2/s Neutron Program for Materials Flux: 8.7 x 1013 n/cm2/s Scientific Coordinator Research Address for application forms and Dr. G. Cicognani, ILL, BP 156, National Research Council Canada informations: 38042 Grenoble Cedex 9, France Building 459, Station 18 Reinhard Kampmann, Institute for Tel: +33 4 7620 7179; Fax: +33 4 Chalk River Laboratories Materials Science, Div. Wfn- 76483906 Chalk River, Ontario Neutronscattering, GKSS, Research E-mail: [email protected] and [email protected] Canada K0J 1J0 Centre, 21502 Geesthacht, Germany http://www.ill.fr Phone: 1 - (888) 243-2634 (toll free) Tel: +49 (0)4152 87 1316/2503; Fax: Phone: 1 - (613) 584-8811 ext. 3973 +49 (0)4152 87 1338 Fax: 1- (613) 584-4040 E-mail: IPNS Intense Pulsed Neutron at http://neutron.nrc- [email protected] Argonne (USA) cnrc.gc.ca/home.html http://www.gkss.de for proposal submission by e-mail send to [email protected] or mail/FAX to: Budapest Neutron Centre BRR (H) HMI Berlin BER-II (D) IPNS Scientific Secretary, Building Type: Reactor. Flux: 2.0 x 1014 Facility: BER II, BENSC 360 n/cm2/s Type: Swimming Pool Reactor. Flux: Argonne National Laboratory, Address for application forms: 2 x 1014 n/cm2/s 9700 South Cass Avenue, Argonne, Dr. Borbely Sándor, KFKI Building Address for application forms: IL 60439-4814, USA 10, Dr. Rainer Michaelsen, BENSC, Phone: 630/252-7820, FAX: 1525 Budapest, Scientific Secretary, Hahn-Meitner- 630/252-7722 Pf 49, Hungary Insitut, http://www.pns.anl.gov/ E-mail: [email protected] Glienicker Str 100, 14109 Berlin, http://www.iki.kfki.hu/nuclear Germany Tel: +49 30 8062 2304/3043; IRI Interfaculty Reactor Institute in Fax: +49 30 8062 2523/2181 Delft (NL) E-mail: [email protected] Type: 2MW light water swimming http://www.hmi.de/bensc pool. Flux: 1.5 x 1013 n/cm2/s Address for application forms: Dr. A.A. van Well, Interfacultair

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Reactor Institut, LLB Orphée Saclay (F) PSI-SINQ Villigen (CH) Delft University of Technology, Type: Reactor. Flux: 3.0 x 1014 Type: Steady spallation source. Mekelweg 15, n/cm2/s Flux: 2.0 x 1014 n/cm2/s 2629 JB Delft, The Netherlands Laboratoire Léon Brillouin (CEA- Contact address: Tel: +31 15 2784738; CNRS) Paul Scherrer Institut Fax: +31 15 2786422 Submissio by email at the following SINQ Scientific Coordination Office E-mail: [email protected] address : CH-5232 Villigen PSI http://www.iri.tudelft.nl [email protected] Phone: +41 56 310 2087 http://www- Fax: +41 56 310 2939 llb.cea.fr/index_e.html E-mail: [email protected] ISIS Didcot (UK) http://sinq.web.psi.ch Type: Pulsed Spallation Source. Flux: 2.5 x 1016 n fast/s NFL Studsvik (S) Address for application forms: Type: 50 MW reactor. Flux: > 1014 SPALLATION NEUTRON SOURCE, ORNL ISIS Users Liaison Office, n/cm2/s (USA) Building R3, Address for application forms: http://www.sns.gov/ Rutherford Appleton Laboratory, Dr. A. Rennie, Chilton, NFL Studsvik, S-611 82 Nyköping, Didcot, Oxon OX11 0QX Sweden TU Munich FRM, FRM-2 (D) Tel: +44 (0) 1235 445592; Tel: +46 155 221000; Fax: +46 155 Type: Compact 20 MW reactor. Fax: +44 (0) 1235 445103 263070/263001 Flux: 8 x 1014 n/cm2/s E-mail: [email protected] E-mail: [email protected] Address for information: http://www.isis.rl.ac.uk http://www.studsvik.uu.se Prof. Winfried Petry, FRM-II Lichtenbergstrasse 1, 85747 Garching JAERI (J) NIST Research Reactor, Washington, Tel: 089 289 14701 Japan Atomic Energy Research USA Fax: 089 289 14666 Institute, National Institute of Standards E-mail: [email protected] Tokai-mura, Naka-gun, and Technology-Gaithersburg, http://www.frm2.tu-muenchen.de Ibaraki-ken 319-11, Japan. Maryland 20899 USA Jun-ichi Suzuki (JAERI); Center Office: Yuji Ito (ISSP, Univ. of Tokyo); J. Michael Rowe, 6210, Director Fax: +81 292 82 59227 NIST Center for Neutron Research telex: JAERIJ24596 [email protected] http://www.ndc.tokai.jaeri.go.jp/ http://www.ncnr.nist.gov/

JEEP-II Kjeller (N) NRI Rez (CZ) Type: D2O moderated 3.5% Type: 10 MW research reactor. enriched UO2 fuel. Address for informations: Flux: 2 x 1013 n/cm2/s Zdenek Kriz, Scientif Secretary Address for application forms: Nuclear Research Institute Rez plc, Institutt for Energiteknikk K.H. 250 68 Rez Bendiksen, Czech Republic Managing Director, Tel: +420 2 20941177 / 66173428 Box 40, 2007 Kjeller, Norway Fax: +420 2 20941155 Tel: +47 63 806000, 806275; E-mail: [email protected] / [email protected] Fax: +47 63 816356 http://www.nri.cz E-mail: [email protected] http://www.ife.no

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