High Order Mode Heating Observations in the PEP-II Interaction Region

High order mode (HOM) heating is observed in the PEP-II [1] interaction region vacuum system by monitoring chamber temperatures in several locations. The region where the electron and positron beams enter a common chamber results in a RF cavity where the beams generate HOM heating. By determining the temperature dependence on beam current, beam bunch length, and phase of the two beams, information about the modes is extracted. The time response of the temperature and the geometry also aid in determining the source of the heat flow