UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20200824

2020/08/24 (Monday)

Previous Day

  • Lab in-person: Zach
  • Virtual partner: Michael, Nick
Setup Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on overnight. Lead/poly shield erected (4 lead walls, 2 poly walls).
0545 MB = 27.1%. Estimate 20% at 9:44, 15% at 12:32, 10% at 15:19
1040 Zach body temp = 97.5
1130 Zach arrives at lab.
1135 Tower/MC/Coldplate = 53.0/31.7/205 mK, Still = 1.62 K / 0.11 mbar / 0 mW, G1/G2= 165/172 mbar, 1K Pot = 1.69 K / 55±5 mbar.
1045 MB = 17.2%
1152 Begin LHe transfer @ MB = 15.3%
1213 Filled LN2 cold trap dewar.
1230 Ended LHe transfer @ 91.3
Had a hard time plugging the fridge after pulling the transfer stick out.
1325 Closed off IVC from turbo.
1450 Turbo on manifold and hose = 16 nbar. Switched turbo to pump on vacuum jacket instead of IVC. CVJ = 0.25 ubar.
1458 MB = 90.1%
1500 Turbo on CVJ = 6.3 nbar.
1501 CVJ after 1min with turbo valved out = 0.14 ubar.
1505 Zach leaves lab.
2030 Zach body temp = 97.2

Instructions to pump out Cryostat Vacuum Jacket (CVJ):

  1. Close both IVC valves
  2. Close Large Hose valve
  3. Close Turbo Pump valve
  4. Disconnect small KF joint at end of Large Hose from IVC Port
  5. Connect small KF joint at end of Large Hose to CVJ Hose
    1. Clip rope from Fridge Stand around Large Hose to support it, relieving some of the weight on the KF flanges
  6. Plug in Scroll Pump
  7. Open Scroll Pump Valve
  8. Open Large Hose valve
    1. wait until Turbo Manifold pressure is below 0.1 mbar
  9. Open Turbo Pump valve, then close Scroll Pump valve and unplug Scroll Pump
    1. wait a few minutes to pump out line to CVJ thoroughly
  10. Close Turbo Pump Valve, then open CVJ valve, record CVJ pressure
  11. Open Turbo Pump Valve
    1. Now we are pumping out the CVJ. Periodically record the Turbo pressure, then close Turbo valve for 1 minute and record CVJ pressure, then open Turbo valve again. Hopefully CVJ pressure will go down over time.

Instructions to switch from pumping CVJ to pumping IVC:

  1. Close JVC valve
  2. Close Large Hose valve
  3. Close Turbo Pump valve
  4. Disconnect small KF joint at end of Large Hose from CVJ Hose
  5. Connect small KF joint at end of Large Hose to IVC Port
  6. Plug in Scroll Pump
  7. Open Large Hose valve
    1. wait until Turbo Manifold pressure is below 0.1 mbar
  8. Open Turbo Pump valve, then close Scroll Pump valve and unplug Scroll Pump
    1. wait a few minutes to pump out line to IVC thoroughly
  9. Open both IVC valves
Since the partial warmup/cooldown, Main Bath is boiling away faster, as shown in
orange and gray, compared with earlier boiloff periods in blue. Probably
the cryostat vacuum jacket wasn't pumped out thoroughly enough.
We are trying to pump it out more now. We'll see if this boiloff period
(yellow) is slower.
Boiloff Table
time MB [%]
2020-08-24 14:58 90.1
2020-08-24 15:58 89.0
2020-08-24 16:58 87.8
2020-08-24 17:58 86.6
2020-08-24 18:58 85.3
2020-08-24 19:58 83.9
2020-08-24 20:58 82.4
2020-08-24 21:58 80.9
2020-08-24 22:58 79.4
2020-08-24 23:58 78
2020-08-25 0:58 76.3
2020-08-25 1:58 74.8
2020-08-25 2:58 73.3
2020-08-25 3:58 71.7
2020-08-25 4:58 70.2
2020-08-25 5:58 68.6
2020-08-25 6:58 67
2020-08-25 7:58 65.4
2020-08-25 8:58 63.8
2020-08-25 9:58 62.3
2020-08-25 10:58 60.7
2020-08-25 11:58 59.1
2020-08-25 12:58 57.5
2020-08-25 13:58 55.8
2020-08-25 14:58 54.2
2020-08-25 15:58 52.6
2020-08-25 16:58 51
2020-08-25 17:58 49.5
2020-08-25 18:58 47.9
2020-08-25 19:58 46.3

Next Day