UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20241119

2024/11/19 (Tuesday)

Previous Day

  • Lab in-personnel: Himangshu, Myles
Status Run 82 In Preparation
1300 IVC at 7.3e-3 mbar. CVJ pumped out this morning. Continue to LN2 transfer steps
From last cryocleaning yesterday, contaiminants: Cold Trap 1: 40 mbar. Pump out with the scroll pump.
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) = 300 mbar/max out.
  3. Connect scroll pump to He-4 pump line, turn it on.
  4. Open pump line valve, V5A, V2A, V4, wait a minute, then open V5.
  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, V5, V2A, V5A and close and turn off the scroll pump.
1342 G1 remain at zero level. P1 stable at 2000+ mTorr
1344 Placed cold trap 1 in LN2 bath
—- 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 scroll pump valve slowly 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.
1436 Check pressure in 1K Pot by opening the 1kpot speedivalve. G3 went up, but below the 1st least count mark ~ 50 mbar. Pump out with Scroll Pump
1438 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
1442 Open scroll p[ump valve and pump on Main Bath with scroll pump, making sure not to overload the scroll pump.
1511 P2 < 2 mbar, close V1A. P2 was stuck at 9 mbar, proceed with 1k pot pumpout step. Open 1K Pot speedivalve and needle valve (5 turns) to pump out 1K pot volume to < 10e-1 mbar on P2.
1520 Once P2< 10e-1 mbar. Close V4A and scroll pump valve.
We will continue the next steps tomorrow to see if the 40 mbar pressure we see on the Main bath when I close v1a and reopen it later, suggest a leak. I checked with the Leak detector again that the top of the fridge is not leaking.

Next Day