In the Lab Opening and Closing Procedures

1. Wait for IGRINS to warm to room temperature
   1. If you passively let IGRINS warm to room temperature, this takes about 40 hours.
   2. You can decrease the warm time by using the heater ramp function on the bench heaters only.
   3. DO NOT APPLY RAMP HEATING TO THE DETECTORS!
   4. To further decrease the warming time, you can backfill the dewar with dry nitrogen, but this is not recommended.
   
   
2. When all of the internal temperature sensors are approximately at room temperature you can gently release the vacuum using the valve.
   1. Remove the plastic dust cap from the vacuum valve flange
   2. Place clean tissues in front of the flange to filter out dust
   3. Release the lock on the red valve handle by turning it CCW
   4. Gently open the valve by turning it CCW. You will begin to hear air entering the cryostat. Try to limit the airflow to prevent damage to internal components
   5. In general, keeping the backfill noise at the same volume as a whisper will prevent damage.
   6. When the cryostat is backfilled, fully open the vacuum valve and replace the plastic dust cover.

1) Rough pump IGRINS for 36-72 hours depending on if there was a prior partial vacuum.
(A more powerful pump will reduce this time significantly.)
2) Turn on the turbo pump when the pressure is <5 torr.
3) Turn on the He compressor when the pressure is <5e-2 torr.
4) Remove the vacuum pump when the pressure is <5e-6 torr.
5) The final pressure should be <5e-7 torr.