Contents
Part I 1137 pages
- Preface
- HASYLAB in general
- Application Forms at HASYLAB
- Projects at HASYLAB
- List of all Institutes Participating in Experiments at HASYLAB
- Technical Developments
- List of Contributions (Part I)
- Publications in 1997 at HASYLAB
- Author Index of Contributions to the Annual Report (Part I)
Part II Structural Biology, 554 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 1997 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 and PETRA II 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.
Based on the experience gained over the last two years we aim for highly reliable operation of the storage ring DORIS III at 4.5 GeV with high beam stability and a maximum injection current of 150 mA. The aim is to reach beam lifetimes of ~20 hours after injection and ~30 hours at the end of a 10 hours run. In order to reach this goal extensive reconstruction work has been carried out on the DORIS vacuum system and the multi-bunch-feedback system. Moreover, a new PC-based control system was installed which offers new possibilities for optimising the operation of DORIS. To allow for the higher currents a second RF power supply was added.
The reconstruction work at DORIS was carried out in an eight-week summer shut down. Therefore, in 1997 the beamtime for users was separated in two parts: 17. February - 4. August and 29. September - 15. December. Altogether 6 blocks of 5 or 6 weeks duration were available, separated by a week for maintenance or the longer summer shut down. In addition for purposes of DORIS optimisation, an eight-hour machine shift was inserted on the second, third and fourth Thursday of a beamtime block. The average availability of DORIS was 90%, so that from the scheduled 5024 hours of operation for users in the end 4521 hours of dedicated beamtime for synchrotron radiation research were provided in 1997. 808 hours were used for maintenance of DORIS, machine studies, and beamline optimisation. 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.
In 1997 some of the older spectrometers and beamlines at DORIS bending magnets have been modernised or replaced by new instruments. As part of the attempts made to improve the DORIS control system, the vacuum conditions of the HASYLAB beamlines are now monitored by a new PC-based control system. The mountings of the water cooled monochromators and mirrors in the wiggler beamlines have been further improved. The mechanics of the diffractometer at beamline C has been renewed, so that by now robust diffractometers of the Risoe type are in operation at stations BW2, C and W1.
For better adjustment of the beam focus at the small angle scattering camera at the wiggler beamline BW4, the existing toroidal mirror was replaced by two cylindrical ones. The first mirror focuses horizontally, the second one with variable curvature is placed behind the monochromator and focuses in vertical direction. Moreover, a camera for small angle scattering under grazing incidence was put into operation, and a CCD detector for high count rates was tested successfully at BW4. The surface diffractometer installed at beamline BW6 will be dismounted in the winter shutdown 1997/98 so that this wiggler beamline operated by MPG and GBF (Braunschweig) will be used exclusively for protein crystallography in the future.
The container building housing the experimental hutch at beamline X1 (ROEMO 2) was replaced by a more suitable building, which provides more space for experimental equipment and allows the installation of a small chemistry laboratory directly next to the spectrometer. At beamline A1 a new experimental station for absorption spectroscopy was built in collaboration with the group of G. Schuetz (Wuerzburg) and the Physikalisch-Technische Bundesanstalt, Braunschweig, which provides alternatively radiation from either a double monochromator or a high resolution (+--+)-monochromator. Station A1 will offer very good opportunities for the investigation of magnetic properties of matter. For better suppression of higher harmonics at absorption spectroscopy station E4, an additional plane mirror has been installed which allows the user to choose between three different coatings. To support absorption spectroscopy work at HASYLAB, a new EXAFS routine has been implemented in the HASYLAB control and processing programme package SPECTRA.
At beamline G3 a two-crystal diffractometer, originally built by the groups of U. Bonse (Dortmund) and K. Fischer (Saarbruecken) was replaced by two new instruments: A spectrometer for resonant inelastic scattering (group of W. Schuelke, Dortmund) and a diffractometer for position-sensitive investigations of the diffraction properties of polycrystalline materials ("reciprocal space mapping"). In the future the residual strain measurements will be performed by means of this new diffractometer, so that from now on station B2 will be used exclusively for powder diffraction work
The triple-crystal diffractometer at beamline D4, which was originally built by the Physics Department of the Risoe National Laboratory (Denmark), has been replaced in collaboration with the group of J. Als-Nielsen (Copenhagen) by a new diffractometer/reflectometer with new TASCOM control and processing software. The instrument allows for a wide range of surface structure investigations on solid and liquid samples. Because of lack of manpower HASYLAB cannot support the operation of this instrument in the usual way. As already practised at a number of other beamlines, D4 can only be used in agreement with the director HASYLAB by well experienced groups knowing the station in detail. In the future full use of HASYLAB's potential for synchrotron radiation research will increasingly depend on the input from external user groups.
The construction of the Free-Electron Laser for the VUV and soft X-ray spectral range at DESY progresses on schedule. At the TESLA Test Facility the first cryomodule of the superconducting linear accelerator has been put into operation. An average gradient of 16.7 MeV per meter was achieved, which is above the original design value. The quality of the accelerated electron beam met all expectations. Measurements of the magnetic and mechanical properties of the prototype undulator were satisfactory and a call for bids for the 15 m long undulator system has been made. The vacuum chamber in the undulator is designed and built in collaboration with the Advanced Photon Source APS at Argonne National Laboratory (USA). Prototypes of the monitors for electron beam diagnostics have been built and successfully tested at the CLIC test facility at CERN (Geneva). A collaboration of specialists from 8 european countries defined the instrumentation for the characterisation of the FEL radiation. First components are under construction. By the end of 1998, the energy of the LINAC will have been brought up to 390 MeV. After extensive machine studies on the accelerator, the FEL undulator will be installed in spring of 1999. The goal is to demonstrate the SASE principle down to wavelengths of 44 nm in the summer of 1999.
In 1997 the projects for construction of Free-Electron Lasers based on SASE ("Self Amplified Spontaneous Emission") took shape. The synchrotron radiation facilities APS (USA) and SPring 8 (Japan) plan or started construction of Free-Electron Lasers in the spectral range of the VUV and soft X-ray spectral range. At Stanford (USA) the plans for the construction of the LINAC Coherent Light Source (LCLS), which will use part of the existing SLAC LINAC, was discussed with an international team of experts. The goal for the LCLS is to produce X-rays down to a wavelength of 0.15 nm. At DESY the presentation of the "Conceptual Design Report for a Linear Collider with an Integrated X-ray Laser Facility" in May 1997 was a very important milestone. The superconducting linear accelerator allows the construction of a powerful X-ray facility with many beamlines and experimental stations where either radiation from Free-Electron Lasers or the spontaneous emission from normal undulators can be used.
This Annual Report contains 711 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 1997 contains 226 institutes and more than 1290 scientists. In the field of structural biology 629 scientists from 108 institutes, primarily from Europe, used the EMBL beamlines and facilities at DESY. The reports on their experiments have been collected in a second section of the 1997 Annual Report. Besides the main part of the reports on experiments performed at HASYLAB in 1997, 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 1997 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.
Additional travel funds for German HASYLAB users, who do not have funds for research travel, were provided by the German Ministry for Education, Research and Technology (BMBF) and helped very much to make efficient use of the beamtime available at HASYLAB. Thanks to special programs of the European Union the HASYLAB facilities have been opened to a wider European users community. In 1997 about 32% of the external HASYLAB users came from abroad.
At this occasion we would like to thank Professor K. Wilson,who was head of the EMBL outstation in Hamburg for more than 10 years and who moved to the University of York in England, for the very fruitful collaboration. Dr. M. Wilmans was appointed new head of the outstation, Dr. V. Lamzin is his deputy.
Thanks to the high motivation of the HASYLAB staff and of the external users of the laboratory HASYLAB is facing promising years ahead of exciting synchrotron radiation research. The support of synchrotron radiation research by all colleagues at DESY is very much appreciated.
Jochen R. Schneider
Director HASYLAB
