2020/09/18 (Friday)
- Lab in-person: Matt
- Virtual partner: Derek, Zach
| 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 down after warmup to deal with 1K Pot partial blockage, helium in IVC. LN2 transfer yesterday. |
| 0800 | MC(Cernox) = 77.3 K, Sorb = 132.9 K, IVC = 1.6 mbar, G2/G1 = 547/614 mbar |
| 0940 | Matt Fritts body temperature 97.5 F |
| 1050 | Matt arrives in lab |
| 1050 | Start pumping IVC with scroll pump. 5 minutes later switch to Turbo. |
| 1055 | MC(Cernox) = 77.4 K, Sorb = 133.4 K, G2/G1 = 547/614 mbar |
| 1055 | Turn on 3He pump and open V6 to 12.8%, reestablishing circulation like yesterday. G2/G1/P1 → 673/751/3.0 mbar and settle. |
| 1100 | Close V12a speedivalve for 2 minutes to assess throughput. G1 falls at 66.0 mbar/min, good. Reopen V12a speedivalve. |
| 1105 | Pump mixture from fridge and Trap 1 to Dump |
| Throughput test procedure, Cold Trap 1: |
- All mixture in dump, LN2 trap 1 cold, condenser & still valves open (3He pump on - optional)
- Open V9, V13a, V12a+speedivalve, V3. Wait for G1 to be close to G2.
- Close V12a+speedivalve and V3, open V1
- monitor G1
| 1115 | Perform mixture throughput test at MC = 77 K using above procedure with 3He pump on. Let G1 rise to 540 mbar before Step 3, then it falls to 65 mbar, then rises. Throughput = 40.1 mbar/min. Nearly the same as last time, 2020 July 17 |
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| 1120 | Open mixture to both sides of the fridge and cold LN2 Trap 2. |
| 1130 | Begin blowing out LN2. Main bath (G3) = 800 mbar above 1atm. That's kinda high… Adjust cylinder regulator, MB → 670 mbar+1atm. |
| 1145 | MB pressure drops, probably because LHe cylinder is empty. Switch to fresh cylinder. |
| 1150 | MB = 303 mbar+1atm, after adjusting regulator. I guess we are still removing LN2. Actually no, just gas coming out of hose. |
| 1155 | End LN2 blowout, stop pressurizing MB. |
| 1202 | Start pumping out main bath with scroll pump. Takes 10 minutes to fall to 1 mbar. |
| 1205 | Fill LN2 cold trap bath. |
| 1215 | Pressurize MB with helium to 270 mbar above 1 atm. |
| 1220 | 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 0.07 bar. Then pump out 1K Pot (needle valve closed) with Scroll Pump to 0.06 mbar on P2 (not quite as low as last time). Then close 1K Pot speedivalve. Open V1a again to monitor bath pressure. |
| 1225 | Turbo on IVC = 12 nbar. With Turbo valve out for a minute, IVC = 0.14 ubar |
| 1230 | Let 63 μbar He exchange gas into IVC. |
| 1230 | MC(Cernox) = 77.4 K, Sorb = 139 K, IVC = 63 μbar, G1(fridge) = 631.1 mbar. G3(MB) = 238 mbar+1atm. |
| 1240 | Waiting for 250L LHe Dewar, it's almost ready. |
| 1303 | Begin initial LHe transfer |
| 1305 | MC(Cernox) = 78.8 K, Sorb = 152 K, IVC = 63 μbar, G1(fridge) = 630.8 mbar. G3(MB) = 605 mbar+1atm. |
| 1315 | MC(Cernox) = 78.1 K, Sorb = 145 K, IVC = 30 μbar, G1(fridge) = 629.3 mbar. G3(MB) = 454 mbar+1atm. |
| 1315 | Turn on heater on 250L Dewar to 4 PSIG. This causes the MB pressure to rise. (After this the MB varies between about 400 and 500 mbar+1atm) |
| 1325 | MC(Cernox) = 73.0 K, Sorb = 120 K, IVC = 19 μbar, G1(fridge) = 615.1 mbar. G3(MB) = 478 mbar+1atm. |
| 1335 | MC(Cernox) = 64.8 K, Sorb = 91 K, IVC = 14 μbar, G1(fridge) = 584.3 mbar. MB = 2.0% / 509 mbar+1atm. |
| 1345 | MC(Cernox) = 58.6 K, Sorb = 58 K, IVC = 12 μbar, G1(fridge) = 532.1 mbar. MB = 9.9% / 510 mbar+1atm. |
| 1355 | MC(Cernox)/Sorb/1KPot = 52.5/8.5/6.7 K, IVC = 8.6 μbar, G1(fridge) = 490.5 mbar. MB = 27.6% / 475 mbar+1atm. |
| 1405 | MC(Cernox)/Sorb/1KPot = 47.7/7.3/5.8 K, IVC = 7.4 μbar, G1(fridge) = 484.4 mbar. MB = 43.0% / 460 mbar+1atm. |
| Note that LakeShore is on Autorange, so Cernox thermometer shouldn't go out of range. | |
| 1415 | MC(Cernox)/Sorb/1KPot = 43.2/7.2/5.77 K, IVC = 7.4 μbar, G1(fridge) = 480.6 mbar. MB = 63.0% / 449 mbar+1atm. |
| 1425 | MC(Cernox)/Sorb/1KPot = 37.0/7.0/5.60 K, IVC = 6.3 μbar, G1(fridge) = 477.4 mbar. MB = 84.3% / 438 mbar+1atm. |
| 1432 | End LHe transfer @ MB = 91.0% |
| 1500 | MC(Cernox)/Sorb/1KPot = 19.2/5.9/4.78 K, IVC = 4.6 μbar, G1(fridge) = 526.8 mbar. MB = 88.1% / 195 mbar+1atm. |
| 1515 | MC(Cernox)/Sorb/1KPot = 14.7/5.7/4.61 K, IVC = 4.0 μbar, G1(fridge) = 534.4 mbar. |
| 1525 | MC(Cernox)/Sorb/1KPot = 12.6/5.6/4.53 K, IVC = 4.0 μbar, G1(fridge) = 536.5 mbar. |
| 1530 | MC(Cernox)/Sorb/1KPot = 11.6/5.6/4.50 K, IVC = 3.4 μbar |
| 1536 | MC(Cernox)/Sorb/1KPot = 10.0/5.5/4.45 K, IVC = 3.0 μbar Start pumping out IVC with Turbo pump. |
| 1540 | Turbo on IVC = 0.16 ubar. |
| 1540 | Matt leaves lab |
| 1700 | MC(Cernox)/Sorb/1K Pot = 6.11/6.4/5.13 K |
| 1700 | Turn off 3He pump |
| 1710 | Matt Fritts body temperature = 97.6 F |