A study on the possibility to increase the PSR e-p instability threshold

The Proton Storage Ring (PSR) has a fast intensity-limiting instability, which may result from an electron cloud interaction with the circulating proton beam leading to a transverse mode coupling instability. Multipacting may also be very important. A PSR beam experiment is proposed with an available 150-350 MHz RF cavity. This cavity would produce a high frequency longitudinal density ripple on the proton bunch which could reduce the e-p instability by two mechanisms: (1) a /spl sim/350 MHz ripple could clear electrons by creating an unstable parametric resonance between the electrons and protons, and (2) a /spl sim/150 MHz ripple could reduce multipacting by reducing the electron energy at the vacuum chamber.