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Steps 3 will take a long time.  You have to start the procedure well in advance in order to make step 4 at the time you need.

  1. Select a QT liquefier ("Liq") for the magnet filling. Liq should contain at least 200 L of Helium.
  2. Change the mode of Liq to Auto + Idle.
  3. Change the pressure set point of Liq to 4.0 psi.  It will take >1 hour for the pressure to go down to the set point.
  4. Start to cool down the transfer line by opening VPC and VJVA/B.
    1. This is the start time of the transfer.  Record the time, the magnet level and the Liq level.
  5. Monitor TX1 and wait until it reaches below 100K (for ~10 minutes). 
    1. Usually TX1 first rises slightly (by 1-2 K).
  6. Disable the auto control of the MagRetBypass valve. 
  7. Open the MagRetBypass valve fully.
  8. Open VJVT and close VPC.
  9. Change the mode of Liq to Manual + Idle.
  10. Open SV501A/B.
  11. Set FC501A/B at 60 SLM.
    1. If the actual inflow (FC501A/BI) is lower than its set point (FC501A/BQ), change the mode of the other liquefier to "Idle" so that PT501A/B rises.
  12. Turn off all the five cold heads of Liq. 
    1. Confirm that the pressure of Liq is increasing.
    2. If it isn't, turn on all the five heaters of Liq until the pressure differential (between Liq & Mag) becomes 3.0 psi.  Then turn them off.
  13. Wait until the pressure differential (between Liq & Mag) becomes 3.5 psi.
    1. Usually the magnet pressure (PTMR3) goes up to 2.0 psi and then down slowly to 1.5 psi.
  14. Set FC501A/B at 55 SLM.
  15. Maintain the pressure differential at 3.0-3.5 psi, by adjusting FC501A/B.
    1. Usually you change FC501A/B with a step of 5 SLM down to 40 SLM (i.e. 50 → 45 → 40 SLM).
    2. You have to increase FC501A/B when the pressure differential becomes smaller than 3.0 psi.
  16. Keep until the magnet level reaches 40% (135 L).
  17. Close VJVA/B.  Open VPC.  Close VJVT.
    1. This is the end time of the transfer.  Record the time, the magnet level and the Liq level.
  18. Enable the auto control of the MagRetBypass valve.  Change the set point to 1.5 psi if needed.
  19. Turn on all the five cold heads of Liq. 
  20. Wait until the cold-head temperature becomes <10 K.
  21. Change the pressure set point of Liq to the original value set before you started this procedure.
  22. Change the Liq mode to Auto + Liquefy.
    1. If you change the mode of the other liquefier, change it back to Liquefy.
  23. Confirm that the Liq pressure stays around the set point.  If it keeps going up, set the outflow (FCA/B) at 40 SLM, wait for 5 minutes, set it back at 2 SLM, and confirm again.

Previous Version (Until 2023-01-01)

  1. Select a QT dewar for the magnet filling. The dewar should contain at least 200L Helium
  2. Bing the dewar pressure to around 3.5-4 psi by setting the liquefier to Manual+Idle and setting outlet flow to 60 SLM.  This will take around 1 hour (for 6.5 psi to 3.5 psi)
  3. Start to cool down the transfer line by opening VPC and VJVA/B.  Monitor TX1 and wait until it reaches below 100K.
  4. When it is ready, start the transfer to the magnet by following the  sequence 
    1. Fully close the magnet return bypass valve
    2. Open VJVT
    3. Close VPC
    4. Fully Open the magnet return bypass valve
  5. Pserize the dewar by opening SVPA/B to maintain a 3 psi pressure difference between the magnet
  6. monitor the magnet helium level
  7. Stop the transfer when the magnet helium level reaches 40%
    1. Close VJVA/B
    2. Open VPC
    3. Close VJVT
    4. Set the magnet return bypass valve to 1.5 Pid control
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