Contents
Part I 300 pages
- Preface
- HASYLAB in general
- Application Forms at HASYLAB
- Projects
- List of all Institutes and Scientists Participating in Experiments
- Technical Developments
- Publications in 1995
- List of all Contributions (of Part II)
Part II 1100 pages
- List of Contributions
- Author Index of Contributions to the Annual Report
Preface
At the Hamburger Synchrotronstrahlungslabor HASYLAB synchrotron radiation emitted from positrons in the DORIS storage ring is used in many significant ways in fundamental and applied research in the fie lds 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 cover ing an energy domain from about 1eV to 300keV. At nine experimental stations the structure of bio-molecules is studied by scientists and users of the Hamburg Outstation of the European Molecular Biology Laboratory EMBL and by three working groups for structural molecular biology of the Max-Planck-Gesellschaft . HASYLAB contributes to the t raining of students in physics within a close collaboration with the II. Institut für Experimentalphysik of the University of Hamburg.
In 1995 the storage ring DORIS was operated from March 20th to December 18th providing 5140 hours of beamtime for synchrotron radiation research. To allow for experiments which make use of the time struc ture of DORIS, the storage ring was operated in reduced bunch mode for 25% of its running time. In Decmber a peak current of 120mA decreased continuously to about 50mA within 10 hours when DORIS was operated in five-bunch mode. In two-bunch operation the maximum current stored was 80mA. The operation of DORIS in blocks of four weeks for synchrotron radiation experiments followed by one week for maintenance of the storage ring and the beamlines, as well as for machine studies, proved to be very efficient.
The performance of existing beamlines and instrumentation was further improved in 1995 and additional upgrades are under way. The new double monochromator RÖMO II for absorption spectroscopy at the bending magnet beamline X operates to the full satis faction of a broad user community. At the VUV-undulator beamline BW3 a new refocusing optics has been installed, which leads to a considerable reduction of the beam cross section at the entrance slit of the seconda ry spectrometer and to substantial increase of the available flux. At the small angle scattering camera at wiggler beamline BW4 two dimensional diffraction patterns can now be measured on an absolute scale. At wiggler beamline BW5 the 3-crystal diffractometer for high energy synchrotron radiation is now in routine operation. At wiggler beamline BW6 for protein cristallography the wavelength monitor has been further developed an d it now allows for reliable measurements at the absorption edge of specific atoms and thus for successful MAD experiments for phasing protein crystal structures. Important progress has also been made in the developement of new optical elements for wiggle r beamline BW2 . A new concept for cooling the first plane mirror avoids the mechanical distortions of the mirror observed so far sideways cooling. By means of a sagittal focusing monochromator and a mirror mounte d on a new bender, which allows for cylindrical bending to various curvatures, the focus can be moved to the sample position of three different spectromemters arranged sequentally in the experimental hutch of beamline BW2.
On March 25th 1995 synchrotron radiation from the undulator beamline at the PETRA storage ring was observed for the first time in the new experimental hall. Since then a beamline for high energy synchro tron radiation has become operational and the first successful experiments have been performed. In April 1995 the new HASYLAB office and laboratory building was ready to move in. With 1641sqm of additional space the building meets the growing needs of HAS YLAB, of various guest groups on site devoted to structure determination of bio-molecules, and of the large number of external users of the HASYLAB facilities.
The 1995 Annual Report contains 540 reports on experiments performed in this year at HASYLAB. The list of groups involved in the preparation and performance of experiments at HASYLAB in 1995 contains 246 institutes and more than 1217 scientists. Thanks to special programs of the European Union the HASYLAB facilities were opened to a wider European users community. In total about 30% of the external HASYLAB users came from abroad. In addition, 492 scientists from all over Europe used the EMBL beamlines at HASYLAB.
Significant progress has been made in developing long term collaborations with industry. So far contracts have been signed with four companies, a fifth contract is expected to be signed early 1996, and two scientists are employed for the Industrial Servic e Group at HASYLAB.
In 1995 some of the main subjects of research at HASYLAB were discussed with colleagues from Germany and abroad in several workshops. From October 9th to 13th, R. Frahm, J. Feldhaus and L. Tröger organized a school on absorption spectroscopy, which o ffered the 30 participants tutorial talks as well as the opportunity to perform experiments at HASYLAB beamlines. Th. Brückel, W. Laasch and J.R. Schneider organized an international workshop on scattering experiments with high energy synchrotron rad iation for 54 participants, which was held in Schwerin from October 29th to November 1st and concluded with a visit to HASYLAB.
In 1995 pictures of coronary arteries patients were taken routinely at the HASYLAB angiography station with injection of the contrast agent into the brachial vein, i.e. without using any catheter. After many years of developement work these pictures are n ow of clinical significance and were in the center of attention at an international workshop on coronary angiography with synchrotron radiation organized by W.-R. Dix (HASYLAB), C. Hamm (University Hospital Hamburg Eppendorf) and W. Kupper (Heart Center B ad Bevensen) and held at DESY from October 18th to 20th. About one third of the 74 participants were physicians, mainly cardiologists. After a discussion of technical aspects, the potential of coronary angiography with synchrotron radiation for medicine h as been thoroughly discussed and compared to other competing methods. At the concluding panel discussion there was a clear consensus amongst the cardiologists that in 1996, besides some technical improvement, a "protocol" for the systematic examination o f several hundreds of patients should be defined, according to which the method should be validated at DESY in 1997.
Of special importance for HASYLAB and the future of synchrotron radiation research is a "Conceptual Design Report" which was worked out for a VUV Free Electron Laser. This device can provide in its fundamental line extremely high photon fluxes of 10**19 p hotons/second in the energy range between 30eV and 200eV at a pulse length of only 500fsec. After preparations reaching back to 1994, T. Möller and B. Sonntag organized a workshop, held at DESY on April 27th and 28th, where different applications of such a VUV FEL were discussed. Thanks to the enthusiasm and the involvement of the synchrotron radiation community an impressive scientific case for such an unique radiation source was presented only a few weeks later (DESY Report, TESLA-FEL 95-03). The c onstruction of the first section of the superconducting linear accelerator (TESLA Test Facility - 500MeV) at DESY progresses well and the preparations for the construction of a special undulator needed for the FEL are under way.
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.
J. Schneider
