From HFML-FELIX Wiki
The window exchange wheel (WEW) of FEL2 forms a protection between the FEL beam line and the FELIX optical transport system. It consists of several windows mounted under Brewster's angle on a rotary stage. The operator can select the window.
 | Please note that the window exhange wheel axis mount is spring-loaded. Take care upon disassembly. |
 | Advice: Reassembly of the wheel onto the axis This is somewhat difficult because of the spring. Start by mounting the wheel with two longer M4 screws, then use a screw of intermediate length for the third hole, and work your way down to the original screws. |
