Statistical Analysis of Cavity RF Faults
Abstract
During commissioning of the CEBAF accelerator, it was found that cavities could not be operated reliably at the gradients achieved for short periods during individual cavity commissioning. The principal hypothesis for the cause of the faults seen is charging of the cold ceramic RF window, which is 7.6 cm off the beam axis. Beginning in February 1995, most RF systems faults were automatically logged. Simple statistical analysis of the accumulated fault data was first applied in July 1995, with a substantial drop in fault rate recorded. The intent of the analysis was to predict the gradient for each cavity at which it would fault once every ten days, leading to a fault rate for the machine of about 33/day (330 cavities). This analysis method was pursued through July 1996, with substantial benefit. Cavity gradients were increased for the following six months to check the limits set, and fault rate increased. The methods used for the analysis of the faults recorded between February 1995 and December 1996 will be presented. Results of the analysis fall into a few categories, and typical cavity results will be presented for each.
- Publication:
-
APS Meeting Abstracts
- Pub Date:
- May 1997
- Bibcode:
- 1997APS..PAC..9P61B