Superconducting cavity development at Los Alamos National Laboratory

Single-cell, 3 GHz cavities are being tested to refine cavity processing and assembling procedures. Certain of these results indicated a cavity contamination problem, especially after high-field operation. In this instance, the observed behavior of poorly performing cavities indicated that indium contamination may be responsible. The standard chemical polishing treatment was modified to include a 10 minute pretreatment with pure concentrated nitric acid before the standard 2 minute dip in 1, 1, 1. Preliminary results from five cavity tests indicate that this modification may decrease the number of cavity tests that fall in the lower lobe of the performance distribution.<
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