THE COLLECTOR RING CR OF THE FAIR PROJECT

The Collector Ring is a storage ring in the complex of the FAIR project. It has the purpose of stochastic precooling of both rare isotope and antiproton beams and of measuring nuclear masses in an isochronous mode. The paper discusses progress in the development of magnet systems, rf systems, injection/extraction strategies and stochastic cooling systems. OVERVIEW In the framework of the GSI FAIR project, the main purpose of the CR storage ring is stochastic precooling of both antiproton (pbar) and secondary rare isotope (RI) beams. Furthermore it will be used for mass measurements of short-lived RI beams in an isochronous mode, which means that the ring is operated at transition energy [1]. The maximum magnetic rigidity is 13 Tm, the circumference is 210.451 m. The CR is housed in a common building with the RESR [2], the accumulator ring for antiprotons. Its beam plane lies 1.2 m below the one of the RESR, 1.3 m above ground floor level. Seen from above, its beam orbit is situated roughly 3 m within the RESR beam orbit. Therefore the beam line connecting both rings has both horizontal and vertical deflector magnets. Its optics is based on an achro