UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20180515

2018/05/15 (Tuesday)

Previous Day

Status: Transferred LN2 yesterday. Still and MC heaters on @ 20 mW (oops)
0850 IVC = 1.6 mbar. Start pumping out IVC with scroll, then turbo pump
0850 Turn off MC and Still heaters
0955 Fill LN2 cold trap bath
0855 MC(Cernox)/Sorb = 77.2/122.8 K, Fridge(G1) = 589 mbar
1020 Try Mini-throughput check: close off Trap 2 and V3. Only V1, V9, condenser speedivalve, still gate valve open. Turn on 3He pump, then open V6 to 12.8%. This pumps mix out of the still side and we can see if the pressure goes down on the condenser side. G1 (condenser) starts out at 590 mbar, then falls steadily at 41 mbar/min.
1025 IVC leak = 1090 pbarL/s, New level resistor = 2.982 kΩ
1025 Start blowing out LN2
1030 IVC leak = 1050 pbarL/s, Main bath = 455 mbar above 1 atm, New level resistor = 2.975 kΩ
1035 IVC leak = 964 pbarL/s, Main bath = 434 mbar above 1 atm, New level resistor = 2.970 kΩ
1038 77 K electrical check looks good.
1040 IVC leak = 912 pbarL/s, Main bath = 431 mbar above 1 atm, New level resistor = 2.970 kΩ
1045 IVC leak = 870 pbarL/s, Main bath = 427 mbar above 1 atm, New level resistor = 2.971 kΩ
1050 IVC leak = 826 pbarL/s, Main bath = 429 mbar above 1 atm, New level resistor = 2.973 kΩ
1055 IVC leak = 809 pbarL/s, Main bath = 426 mbar above 1 atm, New level resistor = 2.974 kΩ
1100 IVC leak = 784 pbarL/s, Main bath = 427 mbar above 1 atm, New level resistor = 2.976 kΩ
Throughput test procedure, Cold Trap 2:
  1. All mixture in dump, LN2 traps cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13b, V12b+speedivalve, V3. Wait for G1 to be close to G2.
  3. Close V12b+speedivalve and V3, open V1
  4. monitor G1
1510 Perform mixture throughput test at MC = 77 K using above procedure with 3He pump on. Let G1 rise to 565 mbar before Step 3, then it falls to 64 mbar and starts to rise. Throughput = 45.4 mbar/min.
1105 IVC leak = 763 pbarL/s, Main bath = 378 mbar above 1 atm, New level resistor = 2.983 kΩ
1110 IVC leak = 770 pbarL/s, Main bath = 159 mbar above 1 atm, New level resistor = 2.955 kΩ
1114 Stop pressurizing main bath
1115 IVC leak = 787 pbarL/s, New level resistor = 2.948 kΩ
1120 Pump out main bath with scroll pump. Falls below 1 mbar in about 10 minutes
1135 Check pressure in warm LN2 Trap 1: 16.2 mbar. Pump out with scroll pump.
1140 Let mixture into fridge from dump through cold LN2 Trap 2. Turn off 3He pump.
1145 Pressurize MB with helium to 190 mbar above 1 atm.
1145 Check pressure in 1K Pot: 110 mbar. Pump out with scroll pump for several minutes, down to 0.11 mbar.
Reducing the pressure of the 1K Pot caused a sudden decrease in Sorb temperature, 125→113 K
1155 IVC leak = 640 pbarL/s
1200 Let 63 μbar He exchange gas into IVC.
1205 MC(Cernox) = 77.3 K, Sorb = 119.7 K, IVC = 63 μbar, G1(fridge) = 596 mbar.
1220 Begin initial LHe transfer
1225 MC(Cernox) = 77.6 K, Sorb = 131.3 K, IVC = 63 μbar, G1(fridge) = 594 mbar.
1235 MC(Cernox) = 77.0 K, Sorb = 130.1 K, IVC = 30 μbar, G1(fridge) = 593 mbar.
1300 MC(Cernox) = 60.6 K, Sorb = 65.9 K, IVC = 12 μbar, G1(fridge) = 558 mbar, MB = -0.5%
1310 MC(Cernox) = 54.8 K, Sorb = 27.7 K, IVC = 10 μbar, G1(fridge) = 518 mbar, MB = 4.7%
1320 MC(Cernox) = 49.3 K, Sorb = 7.8 K, IVC = 8.6 μbar, G1(fridge) = 473 mbar, MB = 10.3%
1330 MC(Cernox) = 44.2 K, Sorb = 7.5 K, IVC = 7.4 μbar, G1(fridge) = 465 mbar, MB = 17.2%
1340 MC(Cernox) = 37.9 K, Sorb = 7.1 K, IVC = 7.4 μbar, G1(fridge) = 460 mbar, MB = 27.2%
1350 MC(Cernox) = 30.5 K, Sorb = 6.7 K, IVC = 6.3 μbar, G1(fridge) = 457 mbar, MB = 36.4%
1400 MC(Cernox) = 19.3 K, Sorb = 6.0 K, IVC = 1.9 μbar, G1(fridge) = 453 mbar, MB = 45.4%
1405 MC(Cernox) = 10.0 K, IVC = 0.74 μbar
Start pumping out IVC with turbo pump
1410 MC(Cernox) = 4.7 K, Sorb = 5.5 K, G1(fridge) = 442 mbar, MB = 54.7%
1415 Fill LN2 cold trap bath
1420 MC(Cernox) = 4.5 K, Sorb = 5.6 K, G1(fridge) = 440 mbar, MB = 64.0%
1430 MC(Cernox) = 4.4 K, Sorb = 5.8 K, G1(fridge) = 439 mbar, MB = 73.0%
1440 MC(Cernox) = 4.4 K, Sorb = 5.9 K, G1(fridge) = 440 mbar, MB = 77.4%
1443 End LHe transfer @ MB = 71.3%
1525 Turbo on IVC = 1.6 nbar

Next Day