Due to the amount of Tritium that exists in the 45R beam line, and a detectable release of this Tritium during pumping, the following procedure is used every time the beam line is shutdown for venting or regeneration:
  - Close gate valves and turn off ion gauges, glass tube and nude controlled by Fredericks Televac controller.
  - Turn off cryopump compressor and note the time.
  - After one hour rough each cold head until roughing vacuum is 100 microns, close roughing valves.
  - After half of an hour, repeat the roughing process to 100 microns.
  - After 15 minutes, repeat the roughing process to 100 microns.
  - After another 15 minutes, repeat the roughing process to 100 microns.
  - After 2 hours of total elapsed time, the cold heads should be warm and may be vented or pumped down for re-start.