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2025/10/13 (Monday)

Previous Day

  • Lab in-personnel: Himangshu
– IVC and CVJ pumping over the weekend. Preparing for LN2 transfer
11 Trap warmed up to room temperature this morning.
11:30 Open V3. Reading pressure ~150 mBar. Use the scroll to pump out the trap.
11:33 Close port to CVJ to stop pumping on it.
1133 cold trap 1 in LN2 can.
Pump out fridge lines:
  1. Make sure mixture is isolated in the dump.
  2. Check fridge pressures by opening condenser speedivalve+V1 and still gate valve: LHe trap+Condenser(G1)/Still(P1) = (47.5-2.4=) 45.1/0.13 (1.2-0.07)) mbar.
  3. Connect scroll pump to He-4 pump line, turn it on.
  4. Open pump line valve, V5A, V2A, V7, V2, wait a minute, then open V3.
  5. You're now pumping on the fridge lines. Wait until P1 and G1 flatten out.
  6. Close condenser speedivalve and still gate valve, V1, V3, V2, V7, V2A, V5A and close and turn off the scroll pump.
1145 Pump out 1kpot and main bath:

- Get to baseline on G3 by opening scroll pump valve and V4A. G3 at 0 mbar.

  1. Close scroll pump valve and V4A
  2. Check pressure in 1K Pot on G3 by opening the 1kpot speedivalve. Open V4A and slowly pump out with Scroll Pump by opening the scroll pump valve slowly connected to the 4He line.
  3. Close the 1kpot speedivalve and V4A. close the scroll pump valve.
  4. Open V1A which opens up the line to the main bath (this will cause the line to expand as the gas fills it).
  5. Open V4A and pump on Main Bath with scroll pump, making sure not to overload the scroll pump.
  6. Once P2 < 2 mbar,close V1A and open 1K Pot speedivalve and needle valve (5 turns) to pump out 1K pot volume to < 10e-1 mbar on P2.
1330 Check pressure in 1K Pot by opening the 1kpot speedivalve. G3 went up, but below the 1st least count mark ~ 20 mbar. Pump out with Scroll Pump
1218 Close 1kpot speedivalve, close scroll pump valve, open V1A which opens up the line to the main bath (this will cause the line to expand as the gas fills it). G3 reads 950 mbar
Main Bath Line has a leak which is causing P3 to be above 40 mbar. This can't explain the fridge issues we have, but certainly needs to be fixed. We will continue LN2 transfer tomorrow after fixing this leak.
Check Main Bath for any IVC leak:
  1. leak detector on IVC.
  2. Pump out Main Bath with scroll pump. Add He-gas to Main Bath.
  3. Monitor Leak detector for any changes.

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