The GSI future project. An international accelerator facility for beams of ions and antiprotons

Based on the attained experiences and technological developments, the GSI Laboratory (Gesellschaft fur Schwerionenforschung) at Darmstadt/Germany is proposing a new facility that will boost the intensity of the beam by a factor of 100 to 10000 and increase the beam energy 15-fold. The planned future facility is based on two superconducting synchrotrons and a system of associated storage ring. It will use the present accelerators, the universal linear accelerator (UNILAC) and the synchrotron accelerator (SIS18) as injector. The new large dual ring accelerator (SIS 100/200) with about 1100 meters of the circumference will be installed in a tunnel system 24 m below ground, while the other buildings and facilities will be arranged above ground. Approximately eight years have been planned for realization of the project that is a challenge not only for the physicists but also for the survey and alignment group. At this stage to tolerance are assumed to be in the range of a few tenth of millimeter (relative), depending on the machine. Radiation protection requirement will results in an effective inner tunnel diameter of 5 m, compared to the exterior diameter of 8 m. Direct linkage of the machine reference systems using sight pipes will not be possible due to thick radiation protection walls. The basic necessity for using automated, remote systems for position control and realignment within this zone is therefore obvious. The survey and alignment of the new facility presents many challenges to a survey and alignment group, which still has to be set up, to work on these tasks. (Y. Tanaka)