Investigation of ion effects in the SRRC storage ring by venting H/sub 2/ gas

The instabilities produced by ions are one of the issues in the electron storage ring. At SRRC, H/sub 2/ ion is the dominate species. Comparing with other species, H/sub 2/ ions are difficult to trap from the conventional ion points of view for its small atomic mass. H/sub 2/ ions could introduce fast beam ion instabilities. In order to understand more details of the ion produced instabilities in the ring, H/sub 2/ gas was intentionally vented into the ring chamber. In this paper, the instabilities which relate to the H/sub 2/ ions are described and the physics is also discussed.