DESY 08/2008 Newsletter of the informFORM ª Research Centre DESY

Hidden Van Gogh Picture Uncovered HASYLAB helps art historians to reveal a hidden Van Gogh

Van Gogh’s pictures are fascinating – even more so when one masterpiece conceals another one under its surface. At HASYLAB, an expert team from Belgium and the Netherlands has revealed a hidden Van Gogh painting. Materials scientist Joris Dik from Delft University, conservator Luuk Rutgers van der Loeff from Kröller-Müller Museum in Otterlo and chemist Koen Jansens from Ant- werpen University were thrilled to be able to reconstruct not only a sketch but a real painting – the portrait of a peasant woman. Previous research had already shown the vague outline of a head under- neath the painting entitled “Grasgrond” (grassy landscape). For a clear identifi - cation, however, the picture had to travel Karen Rickers-Appel at the experiment: With intense synchrotron radiation the team of experts was able to measure to Hamburg. very small amounts of mercury and antimony in the lower layers of paint. Preparations for the revealing measure- ments at DORIS were quite sophisticated: traceable in low concentration, the in- From the exchange of letters it is known an insurance, special transport and air- tense antimony fl uorescence line reveals that he had sent some of these portraits conditioning of 55 percent humidity at the bright areas of nose and chin. Pig- to his brother Theo, who was an arts 24 degrees were absolutely essential. ments containing mercury were used for dealer in Paris. When Van Gogh came to DORIS coordinator Wolfgang Drube and the reddish lips and cheeks. The scien- Paris one year later, the artist might scientist in charge Karen Rickers-Appel tists examined the chemical mixture of have deemed his painting too old-fash- made sure that the experiment ran the pigments with the help of absorption ioned, which is why – the experts be- smoothly. For the fi rst time such a paint- spectroscopy at HASYLAB’s beamline lieve – he painted it over. (she) ing has been made visible using a special C. They identifi ed a pigment which is measuring method: micro X-ray fl uores- characteristic for Van Gogh: Naples yel- cence analysis. Using so-called dot low (lead antimonite). The colour of the measuring, the picture is scanned dot mercury compound is vermillion, i.e. per dot without damaging it. The kind mercury sulphide. These analyses creat- and quantity of the elements were ana- ed a detailed coloured reconstruction of lysed this way, making the distribution the underlying picture and led to new of the pigments visible. Two elements answers. Van Gogh painted his portrait were especially important in this analysis: of a peasant woman in the early period Without damaging the masterpiece, the exact colour antimony and mercury. Although only in Nuenen, between 1884 and 1885. gradients of the hidden painting could be revealed.

Patented Performance

The European Patent Offi ce has granted a patent for a lysts. Its modular and compact design makes it possible design developed by Karsten Hansen and his group FEC. to place several of these modules around a sample and Their silicon drift detector module is able to measure to measure simultaneously in various spatial directions. the spectrum of fl uorescent light of samples examined Apart from the compact shape, the patented detector has with synchrotron radiation very quickly and nearly un- very sophisticated interference resistance and cooling. disturbed. This can for example be used for testing cata- DIRECTOR’S CORNER

Particle physics rarely goes Alliance and on networking fi rst particles to circle the ring ceremony at CERN. In Ger- on summer holidays, and this with our partners, and we are by the end of the month. The many, we will have an event year is no exception. Quite facing an exciting future at fi rst collisions can be expect- at the large LHC exhibition the contrary: my deputy and DESY, with our research ed a few weeks later. How- that starts on 14 October in I, the leaders of the research projects completely main- ever, I’d rather not predict Berlin, with the participation groups and my colleagues tained. This is also relevant when we will have the fi rst of DESY in a leading role. For from the directorate are all for my succes sor, who will scientifi c results! I cannot im- one month, you will have the very busy planning the future soon be announced offi cially. agine a more exciting time, opportunity to get a lot of in- of particle physics at DESY We all can hardly wait for the and DESY is right in the formation on the LHC and for the coming fi ve years. We moment when the fi rst protons middle of it all with the ex- Germany’s role in this project are currently drafting the pro- are injected into the Large periments, computing and in the new subway station posal for the next programme- Hadron Collider at CERN. communication. “Bundestag”. oriented funding period 2010 The eight sectors are already Make sure to mark the date of to 2014, which will then be cooled down, but not all sec- 21 October in your calendars. Yours, evaluated internationally. We tors have reached the opera- This is the day of the offi cial Rolf Heuer are putting great emphasis ting temperature of 1.9 Kelvin. LHC inauguration. Many heads on the research fi elds of the Nevertheless we expect the of state are expected at the

Cosmic Particle Symphony with and without Radio Acoustic particle detector to support the neutrino telescope IceCube

by Rolf Nahnhauer IceCube collaboration is discussing to “audible” in a volume a hundred times For the third time since 2005, the year in supplement the neutrino telescope with as large. which DESY in Zeuthen started the series radio and acoustic sensors within a With the help of the South Pole Acoustic “ARENA - Acoustic and Radio EeV radius of ten kilometres. Test Setups (SPATS), developed and Neutri no detection Activities,” around The advantage: radio and acoustic sig- built under DESY leadership, the acoustic 100 physicists from four continents met nals are measurable over distances of properties of Antarctic ice have been in Rome to discuss new procedures for several kilometres. Neutrinos would be tested for one and a half years. SPATS the detection of cosmic neutrinos with consists of four strings, each 400 to 500 highest energies. metres long and carrying seven acoustic The measurement of these neutrinos stations with transmitters and sensors provides important information to cosmo - with a 10 to 100 kHz-range. The fi rst logists, astrophysicists and particle measurement of background noise and physicists. However, detection is diffi cult. acoustic velocity deep down in the ice The expected interaction of neutrinos on make scientists optimistic about this earth is so small that even the volume of method. In contrast, testing the attenua- the cubic-kilometre neutrino telescope tion of acoustic signals in the ice has IceCube can only “see” approximately Deployment of a SPATS string in an IceCube drilling hole taken more time. Results are expected one event per year. This is why the at the South Pole. in the next months.

2 10 Years of Fascination

The study group „Faszination Physik“ (fascination special topics on physics and mathematics. The topics physics) celebrated its tenth anniversary in July. The are selected democratically by the teenagers and presen- project started in 1998 when retired teacher Waldemar ted to each other in lectures. The kids don’t stop at differ- Tausend freund held the fi rst lecture on “Time Travel and ential and integral calculus. New participants are always Paradoxes.” Since then, many sixth form pupils have met welcome. More information (in German): on Saturdays and sometimes also on Fridays to discuss www.desy.de/faszination.physik/ DESY’s EU Projects Japan, to join Professor Koshiba at the University of Tokyo and the experiment seeking proton decays in the mountains HadronPhysics of Japan, in Kamioka. This experiment by Jan Dreyling-Eschweiler paved the way for one of the most im- Particles made of quarks and gluons are portant recent discoveries, the evidence called hadrons – for example the nu- that neutrinos have mass, made by its clear building blocks protons and neu- bigger brother, Super-Kamiokande. trons. The force that is responsible for holding the quarks together with gluons Many prizes have underlined Yoji Totsu- is called the strong force. And every- ka’s outstanding role in this experiment. thing that has to do with this is studied The most prestigious prize in Japan, an by the around 2000 participants of the Order of Culture, was awarded to him EU project “Study of strongly interacting Yoji Totsuka, former Director General of KEK, died at the for his distinguished research in neu- matter”, or in short: HadronPhysics. age of 66 trino physics, in particular for discover- HadronPhysics is an international pro- ing the oscillation of atmospheric muon ject which intends to bring together and neutrinos with the Super-Kamiokande advance this fi eld of research in Europe. detector. He received the prize directly In 2004, the project started with a fund- Remembering from the Emperor of Japan at the Im- ing amount of 17.4 million Euros for fi ve perial Palace. years. A total of 150 research institutes Yoji Totsuka across Europe are participating, includ- From 1996 to 1998 Yoji Totsuka was ing all large European accelerator and by Albrecht Wagner and Rolf Heuer member of DESY’s Physics Research data processing centres. With great sadness and a strong sense Committee (PRC), which advises DESY HERMES is one of the cross-national of loss we have heard that on 10 July in its particle physics programme. initiatives. For example, data from Yoji Totsuka lost his long and brave COMPASS (CERN) and HERMES were struggle against cancer. In 2003 Yoji Totsuka was appointed amalgamated to study the quark spin Director General of KEK, where he played distribution of a proton more closely. Yoji Totsuka worked at DESY from 1972 a key role in positioning the laboratory DESY is also the head of the Compu- to 1976 at DORIS as member of the for the future and in strengthening it to tational Hadron Physics Network which DASP experiment and from 1976 to 1980 play a lead role in the construction of develops methods to numerically solve at PETRA on the JADE ex periment. This J-PARC and the development of the calculations in quantum chromodynam- was the time of small collaborations and International Linear Collider. His close ics (QCD), the theory of hadrons. Under an exciting period where we all worked links to DESY helped a lot in working the name of LatticeQCD, and under the very closely together on the discovery together in the global collaboration to- coordination of Gerrit Schierholz (DESY), of the gluon. Yoji said in a recent article wards the ILC. When he announced that this sub-project will continue to be sup- that DESY was his second home. he would not run for a second term as ported from 2009 on, the starting time of Director General due to health reasons the follow-up project HadronPhysics2. Yoji also became strongly engaged in we were worried and sad. the very intense phase of planning for the OPAL experiment at CERN. OPAL All those who had the pleasure to work was based on the well-tried concept of with Yoji Totsuka share the admiration INFO JADE and became a big success. for him as scientist and the sadness about the loss of a friend. We will keep More on HadronPhysics Before the construction of the OPAL very fond memories of him. http://hadronphysics.infn.it experiment started, Yoji left Europe for

3 Inspiring

The world’s large particle physics centres plan to build a platform developed at CERN. As of 2009 - with easy new scientifi c information system for high-energy physics operation tools and Web 2.0 applications - particle physi- publications’ research. At a meeting in Hamburg at the cists will be able to fi nd the requested publications very end of May, representatives from CERN, Fermilab, SLAC quickly. INSPIRE also provides a vision for information and DESY agreed to start the INSPIRE system. It is being management in other fi elds of science. built by combining the SPIRES database with the Invenio Gateway to Physics On 23 July the moment arrived for 82 students from 20 countries to swap the auditorium for a labora- tory workplace at DESY in Hamburg and Zeuthen. For the majority of the summer students it is the fi rst time that they work as a member of a re- search group. The immersion into experimental practice and the inter- national working atmosphere boosts the motivation of many students. Coordinator Joachim Meyer knows this for a fact because of feedback from surveys he conducts with the students. In nearly eight weeks, the students in physics or related disciplines join Professors from left: Christof Wetterich (Universität Heidelberg), Bernulf Kanitscheider (Universität Gießen), Thomas in day-to-day science and the work Naumann (DESY, Zeuthen), Brigitte Falkenburg (TU Dortmund), Hermann Nicolai (MPI für Gravitationsphysik Pots- of DESY research groups. General dam/Golm) and specialist physics lectures help them to better understand the com- plex experiments. At the end, the students present their projects. In Is Our Universe Unique? mid September they return to their Discussion “Universe – Multiverse” in the Einstein Forum home universities with a lot of new experiences. (she) by Thomas Naumann could say that we live in the one out of Einstein reportedly wondered “whether many worlds that makes our existence God had any choice in the creation of possible. However, this was not the the world”. At the Einstein Forum in solution favoured by the experts at the Potsdam on 8 July, scientists and philo- Einstein Forum. They trust another path: sophers discussed the question why the the search for the fundamental laws Imprint world is governed by so many numbers of the Universe which make our world Publisher the origin of which we do not know. exactly the world it is. With the LHC at DESY-PR Notkestraße 85 Why, for example, is there only the tiny CERN, we hope to make a decisive step 22607 Hamburg, Germany amount of matter left after the Big Bang to discover these laws. Contact email: [email protected] which our Universe is made of? Why do telephone: +49 40 8998-3613 we live in three dimensions while modern www.desy.de/desy_inform INFO (online version + newsletter subscription) string theories predict ten dimensions? In German Editors Why do an electron and a quark have Sandra Hesping (editor-in-chief) www.einsteinforum.de Christian Mrotzek (V.i.S.d.P.) exactly the masses that allow us to exist? www.tagesspiegel.de/magazin/wissen Barbara Warmbein If only one of these numbers was differ- Thomas Zoufal Article: „Der kosmische Jackpot“ ent our world would be hostile to life. Production www.dradio.de/dlf/sendungen Britta Liebaug (layout) Some theories postulate that our Uni- Veronika Werschner (translation) Broadcast: „Viele Welten statt einer“ Kopierzentrale DESY (print) verse is only one of many. Hence we

PETRA III Crew is Moving in

The fi rst PETRA III scientists are now ready to move into touches” on the experimental hall right from their offi ces. their new offi ces on the fi rst fl oor of the experimental hall. Since the offi cial hand-over of the building at the end of Offi ce furniture was delivered last week and the fi rst net- June, the installation of the accelerator and of the experi- work power points were installed. ments is going on at full speed. At the end of July the new Starting in August, a total of 30 persons will be moving in girders were set up. They will carry the magnets that hold gradually. Then they will be able to watch the “fi nishing the electron beam precisely on track.