Studies of a generalized beam-induced multipacting resonance condition

At certain bunch intensities and bunch spacings, beam-induced multipacting (BIM) was observed during experiments performed at the Advanced Photon Source. Dedicated diagnostics known as retarding-field analyzers (RFAs) were used to directly measure the electron flux on the vacuum chamber walls. The peak signals were observed at a bunch spacing other than that predicted in the classical form of BIM, which assumes cold secondary electron emission. Using a simple computer model, we studied the effect of including an energy distribution for the emitted secondary electrons. We found that the experimental data can be explained by a resonance condition in which the secondary electron energy and surface emissivity properties are included. Results for positron beams are presented