Annual Report 1996

Contents

Part I 1000 pages

  • Preface
    •     
  • HASYLAB in general
    •     
  • Application Forms at HASYLAB
    •     
  • Projects at HASYLAB
    •     
  • List of all Institutes and Scientists Participating in Experiments at HASYLAB
    •     
  • Technical Developments
    •     
  • List of Contributions (Part I)
    •     
  • Publications in 1996 at HASYLAB
    •     
  • Author Index of Contributions to the Annual Report (Part I)

Part II Structural Biology, 570 pages

  • Preface
    •     
  • Projects at EMBL and the ASMB-MPG
    •     
  • List of all Institutes participating in Experiments at EMBL and the ASMB-MPG
    •     
  • List of Contributions (Part II)
    •     
  • Publications in 1996 at EMBL and the ASMB-MPG
    •     
  • Author Index of Contributions to the Annual Report (Part II)

Preface

At the HAmburger SYnchotronstrahlungsLAB or HASYLAB synchrotron radiation emitted from positrons in the DORIS storage ring is used in many different ways in fundamental and applied research in the fields of physics, biology, chemistry and crystallography, in materials and geological sciences as well as in medical applications. This is done by using a wide spectrum of electromagnetic radiation ranging from the visible to the hard X-ray regime and covering an energy domain from about 1 eV to 300 keV. At nine experimental stations the structure of biomolecules is studied by scientists of the Hamburg Outstation of the European Molecular Biology Laboratory EMBL and by three research units for structural molecular biology of the Max-Planck-Gesellschaft. HASYLAB contributes to the training of students in physics within a close collaboration with the II. Institute for Experimental - Physics of the University of Hamburg.

In 1996 the storage ring DORIS III was operated from April 29th to December 23rd in seven blocks of four weeks each, separated by a week for maintenance. In addition for purposes of DORIS optimisation an eight hour machine shift was inserted on the second and third Thursday of a beamtime block. This way 4616 hours of dedicated beamtime for synchrotron radiation research and 1096 hours for maintenance, machine studies and beamline optimisation were provided in 1996. To allow for experiments which make use of the time structure of DORIS, the storage ring was again operated in reduced bunch mode for 25% of its running time.

High beam stability, long lifetimes and high reliability of the storage ring had highest priority for DORIS operation in 1996. The result is encouraging: In the five-bunch mode of operation at a positron energy of 4.5 GeV the lifetime increased from ~20 hours after injection to ~29 hours at the end of a filling, i.e. a peak current of 95 mA decayed continuously to a value of about 60 mA in 10 hours. The average availability of DORIS in 1996 was 90%.

At this occasion special thanks are due to Horst Nesemann, who, after 20 years of responsibility for the DORIS storage ring, since 1987 as DORIS coordinator, retired on May 31st. In his succession Ortwin Kaul was appointed DORIS coordinator. H. Nesemann experienced the great time of DORIS in particle physics, minimised the difficulties during parallel use of DORIS for high energy physics and synchrotron radiation research and, after the decision in spring 1993 to operate DORIS exclusively for the production of synchrotron radiation, he made important contributions to keeping HASYLAB as one of the leading synchrotron radiation laboratories in the world by steadily improving the performance of DORIS.

Reliable operation of the DORIS storage ring is of special importance for longer term collaborations with industry in the frame of the HASYLAB cooperation model. So far contracts have been signed with five companies, a sixth contract is expected to be signed in 1997, then three scientists can work in the Industrial Service Group at HASYLAB.

The performance of existing beamlines and instrumentation was further improved in 1996 and additional upgrades are under way. The piezos in the HASYLAB high heat load "Torii" monochromator have been replaced by a novel bending mechanism based on thermal expansion of a metal rod, which now allows to fully compensate the crystal bends caused by the full synchrotron radiation beam from the BW2 wiggler at 90 mA DORIS current. The width of the diffraction pattern agrees with the value for a perfect crystal within a few percent. In addition indirect cooling can now be applied, which considerably simplifies the use of the monochromator. At beamline BW2 a spectrometer for X-ray photoelectron spectroscopy (XPS) using incident photons in the energy range from 2.2. to 10 keV and a commercial SCIENTA SES-200 electron analyser has been installed. The spectrometer allows investigation of the electronic structure of solids by analysing with high energy resolution core states which have not been accessible before. At the wiggler beamline BW4 the installation of a station for nuclear resonance scattering has been accomplished. After termination of the research and development work for the use of anomalous dispersion in sulphur and phosphor atoms for phasing diffraction data taken at large biomolecules at the bending magnet beamline A1, an additional station for absorption spectroscopy will be installed there in 1997.

In addition to the beamline for high energy synchrotron radiation at the PETRA undulator a second beamline for photons in the energy range from 16 to 54 keV has been installed in collaboration with the Niels Bohr Institute of the University of Copenhagen, and the commissioning was started successfully. The two stations can be operated independently. The availability of the PETRA storage ring fully depends on the needs of HERA, by the end of 1996 about 1/3 of the time was available for synchrotron radiation research.

Storage ring based, 3rd generation synchrotron radiation sources perform extremely well and exceed by far their original design goals. However, they do approach the theoretical limit with respect to brilliance and pulse length. On the other hand, linear accelerator driven free-electron lasers based on the principle of self amplified spontaneous emission (SASE) are expected to provide coherent beams of X-rays in the A�ngstrom wavelength regime with time averaged brilliance 5 orders of magnitude higher than the values achieved today at 3rd generation synchrotron radiation facilities. Because of the short pulse length of about 100 femtoseconds and the ten orders of magnitude higher peak brilliances these free-electron lasers are expected to open completely new fields in synchrotron radiation research in physics, chemistry and biology. At DESY the scientific potential of such X-ray FELs has been discussed in two workshops chaired by G. Materlik & R. Johnson and T. Wroblewski & G. Materlik, respectively. To realise these exciting opportunities the final goal at DESY is a FEL laboratory providing radiation in the wavelength range from VUV to hard X-rays as part of a linear collider facility for particle physics. The first version of a Conceptual Design Report will be presented in spring 1997.

The SASE principle has not yet been proven for nm radiation and therefore at various laboratories in the USA, in Japan and in Europe proof of principle experiments are under way. At DESY a SASE FEL for the VUV and soft X-ray regime will be realised in two steps. The SASE principle will be demonstrated at the TESLA Test Facility down to wavelength of 44 nm by the end of 1998. Next the superconducting linear accelerator will be upgraded to an electron energy of 1 GeV and a FEL laboratory for wavelengths down to 6 nm in the fundamental will be built, the possible use of higher harmonics is under study. At a workshop with scientists from eight European countries chaired by B. Sonntag two working groups for photon beam diagnostics have been established which will deal with all aspects of the time structure and the spectral distribution of the FEL radiation. Another focal point of the work in 1997 is the development of instrumentation for flux measurements and of suitable optical components.

The 17th International Conference on X-ray and Inner Shell Processes (X-96) organised by B. Sonntag was the outstanding event in HASYLAB's scientific life in 1996. In the time from September 9th to 13th more than 300 participants from 33 countries discussed at Hamburg University basic aspects of X-ray physics, in general based on recent synchrotron radiation experiments. F.P. Okamura (NIREM, Tsukuba, Japan) and J.R. Schneider organised a German-Japanese Workshop on the use of ultra short wavelength X-rays in structure research, which took place at HASYLAB from March 7th to 10th. Due to the generous financial support by the Japan International Science and Technology Centre JISTEC 42 scientists from Japan and Germany and six colleagues from third countries could participate in the workshop. Following an invitation by T. Wroblewski from April 22nd to 25th twenty scientists from five countries attended a school on powder diffractometry with synchrotron radiation including a one day international workshop with discussions on the research opportunities at modern synchrotron radiation facilities. For the first time a one week student training course in synchrotron radiation research took place at HASYLAB. From November 11th to 15th eight students from the Niels Bohr Institute in Copenhagen performed together with J. Als-Nielsen and K.D. Joensen a series of introductory experiments at the bending magnet beamline D4.

This Annual Report contains 657 reports on experiments performed this year at HASYLAB, including structural biology. The list of groups involved in the preparation and performance of experiments at HASYLAB in 1996 contains 248 institutes and more than 1220 scientists. 506 scientists from 141 institutes from all over Europe used the EMBL beamlines and facilities at DESY. Additional travel funds for German HASYLAB users, who do not dispose of special grants for synchrotron radiation research, provided by the German Ministry for Education, Research and Technology (BMBF), turned out to be very helpful. This way travel costs for additional 162 scientists could be covered by HASYLAB, which was essential for the efficient use of the facility. Thanks go to all who helped to get this program accepted. Thanks to special programs of the European Union the HASYLAB facilities could be opened to a wider European users community. In 1996 about 30 % of the external HA SYLAB users came from abroad.

In 1996 the number of projects in structural biology studied at the DORIS storage ring increased. With the establishment of a laboratory for the research unit for Macromolecular Structure Analysis of the Institutes for Physiological Chemistry and Biochemistry/Food-Chemistry of the University of Hamburg on the DESY site, the opportunities for structural biology at HASYLAB further improved. The reports on experiments in the field of structural biology have been collected in section two of the 1996 Annual Report. Besides the main part of the reports on experiments performed at HASYLAB in 1996, section one of the Annual Report contains general information about using the HASYLAB facilities, a list of the accepted research projects, a list of the institutes involved in the preparation and performance of the experiments, a report on technical developments at HASYLAB, a compilation of titles and authors of the reports on experiments performed in 1996 and a list of publications. As in the preceding years, the authors are fully responsible for the content and the layout of their reports. The short time of only two weeks available for editing does not allow a critical survey on the scientific results to be presented.

Thanks to the high motivation of the HASYLAB staff and of the external users of the laboratory HASYLAB is facing promising years of exciting synchrotron radiation research. The support of synchrotron radiation research by all colleagues at DESY is very mu ch appreciated.

Jochen R. Schneider

Director HASYLAB