The ultra high vacuum system of FAIR (Facility for Antiproton and Ion Research)

The accelerator complex of FAIR is planned to deliver heavy ion beams of increased energy and highest intensity. Whereas the energy is planned to be increased roughly by a factor of 10, the ion beam intensities are planned to be enlarged by three orders of magnitude. An UHV-accelerator system with a base pressure in the low 10E-12mbar regime is required, even under the influence of ion beam loss induced desorption processes. An intensive program was started to upgrade the Ultra High Vacuum (UHV) system of the existing synchrotron SIS18 (bakeable) and to design and lay out the UHV systems of the future synchrotron SIS100 and SIS300 (mainly cryogenic). The strategy of this program includes basic research on the physics of the ion induced desorption effects as well as technical developments, design and prototyping on bakeable UHV components (vacuum chambers, diagnostics, bakeout-control, pumping speed), collimator for controlled ion beam loss, NEG coating and cryogenic vacuum components. The key issues of FAIR relevant UHV R and D and system design are presented