High power tests of the prototype 352 MHz beta 0.85 five cell cavity for the TRASCO project

Abstract

The Five-cell beta 0.85 cavities built at CERN for the development of the TRASCO Project is fully tested at the CERN SL-CT Test Bench. The cavity, built using the standard Niobium on Copper technique, was previously tested in a vertical cryostat, showing Q(sub 0) and field exceeding the design goal for the TRASCO Project (2.5 x 10(exp 9) and 5.5 MV/m at 4.5 K). After the successful test it was decided to check the performances of the cavity installed in a horizontal cryostat and equipped with a LEP-2 type high power main coupler and HOM couplers. The cavity was equipped with the helium tank, tuners and couplers at CERN and tested at the SL-CT facility at CERN under a collaboration agreement between INFN and CERN. The behavior of the fully equipped cavity substantially confirmed the results of the preliminary production tests in the vertical cryostat. The quality factor at low field was substantially unchanged. No MP activity was detected confirming the soundness of the design and the quality of the surface treatment.