Foreword

The past year provided several reasons for GSI to take a look back, far back in certain respects, but also into the future.

GSI celebrated a multiple anniversary: 30 years ago GSI was founded; in addition the last year saw the completion of 25 years of successful operation of the UNILAC accelerator and of 10 years of SIS/ESR. Someone with obviously good mathematics skills pointed out that the anniversaries added up to 65 years, the mandatory retirement age in Germany! So I will quickly add that the past year also saw a major effort to start developing the detailed proposal for the future facilities.

The anniversary event extended over 3 days, with an open house on the first and on the third day, and a celebration and summer party on the second. In wonderful weather everybody, guests and GSI staff, enjoyed the occasion. But perhaps the more significant consequence was that the open house, and more specifically the science exhibit, received such a response and attention that it has since - through word-of-mouth - been on the road as a traveling exhibit from high-school to high-school.

The work on a specific proposal for the future GSI facilities started in the past year. It is based on a range of discussions and workshops at and around GSI over many years that have explored various science opportunities and have provided a basis for the specific concept now under development. The proposal will be completed in 2001 and submitted to the Wissenschaftsrat, the highest scientific advisory committee to the German Federal Government, for evaluation.

After the high-intensity upgrade of the UNILAC over the previous years, the ongoing experimental program went back into full gear in 2000. The HADES di-lepton spectrometer took first data with good lepton identification through the ring imaging Cerenkov counter (see front cover). An experiment with the INDRA set-up from GANIL generated high quality data on nucleus-nucleus collisions, covering the full rapidity range with indications of strong dynamical effects. Analysis of the K-shell pionic atoms of heavy nuclei suggest the possibility to determine the s-wave pion-nucleus potential and the modification of the pion-nucleon coupling constant in the nuclear medium.

The fragment separator provided beams of short-lived nuclei for a range of measurements. Among them are novel studies of spectroscopy on neutron-rich heavy nuclei with gamma-rays, by tagging with K-isomers populated with rather high-spins in projectile fragmentation reactions at 1 GeV/u incident energy.

Elements 111 and 112 were confirmed through new measurements, a requirement set by IUPAC in order to assign discovery to the GSI group. The new even-even isotope ²⁹⁰110 was surprisingly strongly populated (8 events with a-decay chains in 7 days) using the odd-neutron target ²⁰⁷Pb.

The bound beta-decay - capture of the emitted electron in beta-decay into an atomic orbit - which had been observed at GSI indirectly several years ago was now directly observed in the ESR by detecting the Schottky signals of both, mother and daughter nucleus circulating in the storage ring. In studies of short-lived nuclei with ion traps the highest precision Q-value was determined at ISOLTRAP through a mass measurement of the 65 msec nucleus ⁷⁴Kr.

In the biological research program accumulation of a specific (immunofluorescence-stained) protein at the sites of damaged DNA was observed and seen to persist for several hours, thus providing a new sensitive measure for radiation damage studies. The cancer therapy program with 12C beams continued successfully for the full year and in parallel with the science program.

These are just a few selected examples. The total, much broader program generated by a large number of outside users and visitors together with GSI staff is described in this report. This is a good opportunity to thank all contributors for their past work and express best wishes for the successful continuation of an exciting research program.