Cavity C22 reaches its quench limit of 17 MV/m in the Horizontal Test Stand

Cavity C22 reached its quench limit of 17 MV/m in the Horizontal Test Stand on 1 October 2007 . This is the same gradient C22 reached in its vertical test at JLab earlier in the year. Last week cavity C22 reached 15 MV/m; at that point the cavity was limited by electron/vacuum activity.

After a couple nights' worth of cold on-resonance RF processing, this activity cleaned up well and we were able to push the cavity to its quench limit. In addition we were able to get in a little R&D work on measuring the mechanical transfer function of cavities when exciting them with the piezo tuner system

Over the next few days C22 will be removed from the horizontal test cryostat in order to perform modifications to the cryostat's cavity vacuum line. The 3.9 GHz cavity #1 will then be used for a mechanical fit-up in the cryostat, and then re-install C22 and cool it down again in order to gain more operating experience with HTS until the first "production" 3.9 GHz cavity is knocking on the door.