Performance of a 1.3 Ghz Normal-conducting 5-cell Standing-wave Cavity*

A 5-cell, normal-conducting, 1.3 GHz, standing-wave (SW) cavity was built as a prototype capture accelerator for the ILC positron source. Although the ILC uses predominately superconducting cavities, the capture cavity location in both a high radiation environment and a solenoidal magnetic field requires it to be normal conducting. With the relatively high duty ILC beam pulses (1 msec at 5 Hz) and the high gradient required for efficient positron capture (15 MV/m), achieving adequate cavity cooling to prevent significant detuning is challenging. This paper presents the operational performance of this cavity including the processing history, characteristics of the breakdown events and the acceleration gradient witnessed by a single bunch at different injection times for different rf pulse lengths.