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2020/10/07 (Wednesday)

Previous Day

  • Lab in-person: Matt
  • Virtual partner: Zach, Ruiren
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 off. Lead/poly shield erected (4 lead walls, 2 poly walls).
Status Cooling after warmup to deal with clogged 1K Pot. LN2 transfer yesterday.
0850 MC(Cernox) = 77.4 K, Sorb = 137.1 K, G2/G1 (fridge+trap+dump) = 562/612 mbar, 3He pump off
0905 Matt Fritts body temperature = 97.8 F
1050 Matt enters lab
1050 IVC = 1.6 mbar
1050 Start pumping IVC with scroll pump. A few minutes later switch to Turbo.
1050 Turn on 3He pump and open V6 to 12.8%, reestablishing circulation like yesterday. G2/G1/P1 → 684/748/3.6 mbar and settle.
1055 Close V12a speedivalve for 2 minutes to assess throughput. G1 falls at 65.6 mbar/min, good. Reopen V12a speedivalve.
1055 Pump mixture from fridge and Trap 1 to Dump
Throughput test procedure, Cold Trap 1:
  1. All mixture in dump, LN2 trap 1 cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13a, V12a+speedivalve, V3. Wait for G1 to be close to G2.
  3. Close V12a+speedivalve and V3, open V1
  4. monitor G1
1110 Perform mixture throughput test at MC = 77 K using above procedure with 3He pump on. Let G1 rise to 550 mbar before Step 3, then it falls to 70 mbar, then rises. Throughput = 42.0 mbar/min. Nearly the same as last time, 2020 Sep 18
1110 Open mixture to both sides of the fridge and cold LN2 Trap 2.
1115 Begin blowing out LN2. Main bath (G3) = 800 mbar+1atm. That's kinda high… Adjust cylinder regulator, MB → 680 mbar+1atm.
1127 MB pressure dropping, probably almost finished with blowout
1130 MB → 157 mbar+1atm, flattening.
Stop LN2 blowout
1135 Fill LN2 cold trap bath
1135 Start pumping out main bath with scroll pump. Takes 9 minutes to fall to 1 mbar.
1150 Pressurize MB with helium to 260 mbar above 1 atm.
1155 Isolate MB by closing V1a. Pump out line to the G3 volume with Scroll Pump. Isolate pump, then open 1K Pot speedivalve to check pressure: about 0.03 bar. Then pump out 1K Pot (needle valve closed) with Scroll Pump to 0.026 mbar on P2. Then close 1K Pot speedivalve and V4a. Open V1a again to monitor bath pressure.
1205 Turbo on IVC = 6.3 nbar. With Turbo valve out for a minute, IVC = 0.10 ubar
1210 Let 63 μbar He exchange gas into IVC.
1210 MC(Cernox) = 77.5 K, Sorb = 139.8 K, IVC = 63 μbar, G1(fridge) = 628.4 mbar. G3(MB) = 120 mbar+1atm.
1223 Begin initial LHe transfer
1230 MC(Cernox) = 78.1 K, Sorb = 147 K, IVC = 74 μbar, G1(fridge) = 628.7 mbar. G3(MB) = 764 mbar+1atm.
1230 Forgot to open MB recovery valve when I started the transfer - open it now. G3(MB) pressure drops to 260 mbar+1atm, then rises again to 595.
1245 MC(Cernox)/Sorb/1K Pot = 77.1/143/>7 K, IVC = 30 μbar, G1(fridge) = 625.3 mbar. G3(MB) = 439 mbar+1atm.
1300 MC(Cernox)/Sorb/1K Pot = 64.8/95.9/>7 K, IVC = 14 μbar, G1(fridge) = 585.7 mbar. MB = 2.3% / 485 mbar+1atm.
1310 MC(Cernox)/Sorb/1K Pot = 58.0/59.6/>7 K, IVC = 12 μbar, G1(fridge) = 538.3 mbar. MB = 11.9% / 465 mbar+1atm.
1320 MC(Cernox)/Sorb/1K Pot = 52.9/15.5/>7 K, IVC = 10 μbar, G1(fridge) = 494.3 mbar. MB = 27.0% / 437 mbar+1atm.
1330 MC(Cernox)/Sorb/1K Pot = 48.2/7.3/5.84 K, IVC = 8.6 μbar, G1(fridge) = 485.0 mbar. MB = 44.3% / 421 mbar+1atm.
1340 MC(Cernox)/Sorb/1K Pot = 43.2/7.1/5.71 K, IVC = 8.6 μbar, G1(fridge) = 480.5 mbar. MB = 64.0% / 410 mbar+1atm.
1350 MC(Cernox)/Sorb/1K Pot = 37.7/6.9/5.57 K, IVC = 7.4 μbar, G1(fridge) = 477.9 mbar. MB = 84.5% / 398 mbar+1atm.
1355 End LHe transfer @ MB = 90.5%
1415 MC(Cernox)/Sorb/1K Pot = 24.0/6.1/4.92 K, IVC = 7.4 μbar, G1(fridge) = 523.1 mbar. MB = 88.8% / 176 mbar+1atm.
1430 MC(Cernox)/Sorb/1K Pot = 16.8/5.8/4.66 K, IVC = 5.4 μbar, G1(fridge) = 531.5 mbar.
1445 MC(Cernox)/Sorb/1K Pot = 13.1/5.6/4.53 K, IVC = 4.0 μbar, G1(fridge) = 534.6 mbar.
1456 MC(Cernox)/Sorb/1K Pot = 10.0/5.5/4.42 K, IVC = 3.4 μbar
Start pumping out IVC with Turbo Pump
1500 Turbo on IVC = 86 nbar.
1500 Matt leaves lab
1720 MC(Cernox)/Sorb/1K Pot = 4.94/6.8/5.32 K
1720 Turn off 3He pump Looks like I didn't set up remote control, so leaving 3He pump on.
1720 Matt Fritts body temperature = 97.5 F

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