Analysis of collective effects at the diamond storage ring

Abstract

The Diamond storage ring has achieved its nominal operating current of 300 mA in multi-bunch mode and up to 10 mA in single bunch mode. Several collective instabilities have been observed and their dependence on machine parameters such as chromaticity, RF voltage and fill pattern have been investigated. We report here the analysis of the observed current thresholds compared with analytical estimates and tracking simulations. We also present the results of MAFIA simulations performed with the aim of understanding the main contribution to the impedance of the ring and establishing a machine impedance database