Transverse feedback for the ISR

A feedback system designed to assist Landau damping against resistive wall instabilities in the vertical and horizontal planes is described. The purpose of the feedback system is to make it possible to run the ISR with reduced Q-spread, so that low order resonances can be avoided at high intensities. An important problem in the system is the electronic noise of the amplifiers which can cause excessive long-term vertical beam blow-up if the bandwidth is too large. Only four transverse modes are included in the loop. (5 refs).