| | The prototype cryomodule Renascence was constructed as
an energy building block for securing 6 GeV operation of
CEBAF and to validate design elements for future
CEBAF upgrade modules. These elements include the
new "HG" and "LL" 7-cell cavity designs and a new tuner
design.[1,2] Issues were identified during initial testing in
2005. The module has been reworked to address the issues
with thermal stability, component breakage, and tuner
motion. In addition, opportunity was taken to employ
upgraded cleaning and assembly techniques for the cavity
string. The HOM coupler heating issue was resolved, and
seven of the eight cavities in the cryomodule have run
stably at an average of 20 MV/m CW. The cryogenic, rf,
and mechanical performance of the cryomodule are presented. Commissioning in CEBAF has just been completed in October 2007. | |