Filling the chamber with helium

The inboard STXM can be sealed off and refilled with helium to provide a stable helium atmosphere. The controls for the pump and the venting valve are on the interlock box which also shows the chamber pressure on the gauge. We assume that the STXM is open (thus at atmosphere) when we start:

• Close all viewports. Don't tighten screws too hard.
• Close valve V9i.
• Start pumping by pressing the PUMP button. The motor drivers will turn off during at a certain pressure.
• Check that the Helium bottle (at the outboard gas bottle rack) has been opened.
• When the pump has stopped and the VACUUM light is on, press the VENT button. You hear the valve opening and can watch the pressure rising. The motor drivers are turned back on.
• The STXM vent valve will close automatically at a pressure of 600 Torr.
• Open valve V9i.
• Cover viewports and top to exclude ambient light and turn off the VLM illuminator. This is necessary, since currently both x-ray detectors (segmented silicon and luminescence) are sensible to visible light.