Why should we refurbish CEBAF cryomodules?
CEBAF availability at the desired beam energy is limited by cold window and waveguide arc trips. These are thought to be caused by charging of the cold ceramic windows by field emission. Installing doglegs in the cold waveguide should eliminate this. Reprocessing cavities using the latest techniques should also provide useful gradient improvement. Also about half a dozen cryomodules have one or more cavities permanently bypassed due to hurricane damage, helium leaks, tuner failure or other problems.
