A retrofit window design was adapted from FEL and Upgrade window
- Ceramic brazed into Kovar eyelet, brazed to SS flange
Original warm windows were Teflon and polyethylene
- Subject to gas permeation
- Signs of plastic-flow aging
- Several have leaked
Successfully changing out CEBAF rf windows during maintenance downs
- Cryomodule warmed to ~30 K
- Waveguide vented and work performed in helium atmosphere
- Avoids mechanical stress on indium joints.