Acoustic Measurements of RF Breakdown in High Gradient RF Structures

The authors are developing techniques for processing the high gradient (75MV/m) X-band accelerating structures for the NLC. Accelerometers attached to the structures detect surprisingly large acoustic signals believed to be due to RF heating. On a pulse that causes breakdown, these signals increase substantially, producing up to 50 G accelerations at >20KHz. The timing and amplitude of these acoustic signals can provide information on the location and mechanism of the breakdowns.