2019/11/05 (Tuesday)
| Status: Replaced bottom IVC seal Friday. LN2 transfer yesterday. | |
| 0920 | MC(Cernox) = 77.4 K, Sorb = 127.4 K, IVC = 1.6 mbar |
| 0939 | Perform 77K electrical check, no new issues, no show stoppers. |
| 0945 | Turn on 3He pump and open V6 to 12.8%, reestablishing circulation like yesterday. P1 (still) falls to ~10 mbar over a few minutes. |
| 0950 | Begin pumping out IVC, first with scroll pump then turbo pump |
| 0950 | Close V12b speedivalve to assess throughput. G1 falls at 62 mbar/min. We still have throughput! |
| Throughput test procedure, Cold Trap 2: |
- All mixture in dump, LN2 trap 2 cold, condenser & still valves open (3He pump on - optional)
- Open V9, V13b, V12b+speedivalve, V3. Wait for G1 to be close to G2.
- Close V12b+speedivalve and V3, open V1
- monitor G1
| 1015 | Perform mixture throughput test at MC = 77 K using above procedure with 3He pump on. Let G1 rise to 580 mbar before Step 3, then it falls to 80 mbar, then rises. Throughput = 49.3 mbar/min. Decent. A little lower than last time, 2019 Oct 30 |
|---|---|
| 1025 | Start up LD, LD signal on IVC = 55/864 pbarL/s with turbo pump valved in/out. Lower than it was last cool down. |
| 1050 | IVC = 665 pbarL/s |
| 1055 | Begin blowing out LN2. Main bath (G3) = 610 mbar above 1atm. |
| 1050 | IVC = 553 pbarL/s, MB = 654 mbar+1atm |
| 1105 | IVC = 509 pbarL/s, MB = 642 mbar+1atm |
| 1110 | IVC = 463 pbarL/s, MB = 636 mbar+1atm |
| 1115 | MB pressure starts falling, blowout is probably almost finished |
| 1115 | IVC = 441 pbarL/s, MB = 390 mbar+1atm |
| 1120 | IVC = 518 pbarL/s, MB = 215 mbar+1atm and flattening Stop pressurizing main bath |
| smallish increase in leak signal at the end, but lots smaller than before, should hopefully be good this time. | |
| 1125 | IVC = 465 pbarL/s, MB = 99 mbar+1atm |
| 1125 | Start pumping out main bath with scroll pump. Takes 15 minutes to fall to 1 mbar. |
| 1145 | Pressurize MB with helium to 340 mbar above 1 atm. Open 1K Pot speedivalve and needle valve (2 full turns) to repressurize pot as well. Close 1K Pot valves again. |
| 1155 | Let 63 μbar He exchange gas into IVC. |
| 1205 | Begin LHe transfer |
| 1205 | MC(Cernox) = 77.7 K, Sorb = 135 K, IVC = 63 μbar, G1(fridge) = 602.6 mbar. G3(MB) = 480 mbar. MC and Sorb temperatures rising a little. |
| 1215 | MC(Cernox) = 77.6 K, Sorb = 133 K, IVC = 63 μbar, G1(fridge) = 601.5 mbar. G3(MB) = 444 mbar. MC and Sorb temperatures now falling. |
| 1225 | MC(Cernox) = 74.8 K, Sorb = 114 K, IVC = 30 μbar, G1(fridge) = 601.5 mbar. G3(MB) = 362 mbar. |
| 1235 | MC(Cernox) = 66.4 K, Sorb = 85 K, IVC = 19 μbar, G1(fridge) = 587.1 mbar. G3(MB) = 258 mbar. |
| 1245 | MC(Cernox) = 59.9 K, Sorb = 56 K, IVC = 14 μbar, G1(fridge) = 576.7 mbar. G3(MB) = 235 mbar. |
| 1250 | 250L Dewar gauge / MB exhaust gauge / G3 = 1.8 PSI / 1.0 PSI / 245 mbar+1atm. Recovery meter going at a medium speed, around 1 cuft / 12 seconds. Let's try turning on Dewar heater to 4PSI setting. |
| 1250 | Motor A/B = 6.25/6.60 kΩ |
| 1255 | MC(Cernox) = 53.9 K, Sorb = 15 K, IVC = 12 μbar, G1(fridge) = 542.6 mbar. G3(MB) = 315 mbar. |
| 1255 | 250L Dewar gauge / MB exhaust gauge / G3 = 4.0 PSI / 2.7 PSI / 336 mbar+1atm. Recovery meter going faster, around 1 cuft / 8 seconds. But not super fast. |
| 1300 | Level meter starting to register: MB = 12.7% |
| 1305 | MC(Cernox) = 49.0 K, Sorb = 7.0 K, IVC = 10 μbar, G1(fridge) = 467.4 mbar. G3(MB) = 438 mbar. MB = 32.3% |
| 1315 | MC(Cernox) = 43.0 K, Sorb = 7.2 K, IVC = 8.6 μbar, G1(fridge) = 461.0 mbar. G3(MB) = 436 mbar. MB = 54.1% |
| 1325 | MC(Cernox) = 36.9 K, Sorb = 7.0 K, IVC = 8.6 μbar, G1(fridge) = 457.7 mbar. G3(MB) = 419 mbar. MB = 75.4% |
| 1334 | End LHe transfer @ MB = 91.5% |
| 1340 | MC(Cernox) = 26.7 K, Sorb = 6.0 K, IVC = 7.4 μbar, G1(fridge) = 491.9 mbar. G3(MB) = 177 mbar. |
| 1340 | Increase LakeShore bridge resistance range to 2.0 kΩ so it doesn't max out at 632 Ω |
| 1405 | MC(Cernox) = 14.2 K, Sorb = 5.6 K, IVC = 6.3 μbar, G1(fridge) = 511.1 mbar. |
| 1410 | Motor A/B = 6.06/6.39 kΩ |
| 1415 | MC(Cernox) = 11.2 K, Sorb = 5.5 K, IVC = 4.0 μbar |
| 1418 | MC(Cernox) = 10.0 K, Sorb = 5.5 K, IVC = 3.4 μbar Start pumping IVC out with turbo pump |
| 1420 | MC(Cernox)/Sorb/1K Pot = 8.1/5.4/4.4 K, Turbo on IVC = 0.063 μbar |
| 1430 | MC(Cernox)/Sorb/1K Pot = 4.57/5.5/4.44 K, Turbo on IVC = 0.046 μbar |
| 1505 | MC(Cernox)/Sorb/1K Pot = 4.40/6.1/4.90 K, Turbo on IVC = 0.0046 μbar = 4.6 nbar. (down an order of magnitude since 14:30) |
| 1505 | Tower/MC(H35)/Coldplate/Still = 4.39/4.40/12.4/7.8 K looks like Tower and H35 calibrations are OK at 4K, maybe not the other two |
| leaving bridge switched to H35(MC) thermometer | |
| 1530 | MC(H35)/Sorb/1K Pot = 4.40/6.4/5.13 K, Turbo on IVC = 4.0 nbar. With turbo valved out for a minute, IVC = 54 nbar. |
| 1600 | MC(H35)/Sorb/1K Pot = 4.41/6.5/5.21 K |
| 1600 | Fill LN2 cold trap bath from bomb Dewar |