2018/03/20 (Tuesday)
| Status: LN2 transfer yesterday. Mixture in dump/Trap2/fridge. 1K Pot evacuated and isolated. | |
| 0835 | MC(Cernox) = 77.0 K, Sorb = 121.7 K (max), Fridge (G1) = 601 mbar, IVC = 1.6 mbar. unlike last time the IVC pressure has not increased. |
| 0845 | Fill LN2 cold trap bath |
| 0850 | Pump out IVC with scroll pump, then turbo pump |
| 0850 | Close off Trap 2. Meant to do mini-throughput test but accidentally left V3 open, so wound up pumping mix out of fridge. So I'll do a standard throughput check instead. |
| Throughput test procedure, Cold Trap 1: |
- All mixture in dump, LN2 traps 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
| 0855 | Perform mixture throughput test at MC = 77 K using above procedure. Pump on but some mixture has been left in Trap 2. Let G1 rise to 550 mbar before Step 3, then it falls to 86 mbar, then starts to rise. Throughput 41.6 mbar/min. Almost as good as April 4, 2 weeks ago. |
|---|---|
| 1010 | Pump mixture out of cold Trap 2 to dump. Then open mixture from dump through cold Trap 1 to both sides of fridge, 3He pump off. |
| 1100 | Leak detector on IVC, turbo valved out. LD = 410 pbarL/s. |
| 1110 | LD = 370 pbarL/s |
| 1110 | Begin blowing out LN2 into 25L bomb Dewar. G3 (main bath) = 455 mbar above 1 atm. |
| 1115 | LD = 360 pbarL/s. Main bath = 447 mbar. |
| 1130 | LD = 330 pbarL/s. Main bath = 435 mbar. |
| 1150 | LD = 340 pbarL/s. Main bath = 132 mbar. Blowout just about finished |
| 1155 | LD = 400 pbarL/s. Main bath = 125 mbar. Stop pressurizing main bath. |
| 1200 | LD = 380 pbarL/s. Begin pumping out IVC with scroll pump |
| 1210 | Main bath (P2) = 0.65 mbar. LD = 320 pbarL/s. Close V1A, then pump out 1K Pot again. |
| 1215 | Pressurize MB with helium to 260 mbar above 1 atm LD = 290 pbarL/s |
| 1220 | Valve out leak detector and pump IVC with turbo. Turbo pump = 7.4 nbar pumping on IVC. Valve out turbo pump. |
| 1220 | Let 74 μbar He exchange gas into IVC. |
| 1225 | MC(Cernox) = 77.0 K, Sorb = 125.0 K, IVC = 74 μbar, G1(fridge) = 601 mbar. |
| 1240 | Quick electrical check on DIB1&2, look good, consistent with 2018-03-14 check |
| 1242 | Begin initial LHe transfer |
| 1245 | MC(Cernox) = 77.4 K, Sorb = 131.4 K, IVC = 74 μbar, G1(fridge) = 599 mbar. DIB1 qIbias-QET D = 25.43 nS |
| 1255 | MC(Cernox) = 76.8 K, Sorb = 125.1 K, IVC = 46 μbar, G1(fridge) = 598 mbar. |
| 1305 | MC(Cernox) = 73.0 K, Sorb = 108.5 K, IVC = 25 μbar, G1(fridge) = 593 mbar. |
| 1325 | MC(Cernox) = 58.3 K, Sorb = 51.4 K, IVC = 14 μbar, G1(fridge) = 537 mbar. |
| 1345 | MC(Cernox)/Sorb/1K Pot = 45.5/7.5/5.9 K, IVC = 12 μbar, G1(fridge) = 473 mbar, Main bath = 7.4% |
| 1400 | MC(Cernox)/Sorb/1K Pot = 34.5/6.9/5.4 K, IVC = 10 μbar, G1(fridge) = 466 mbar, Main bath = 18.1% |
| 1415 | MC(Cernox)/Sorb/1K Pot = 24.4/6.3/5.0 K, IVC = 8.6 μbar, G1(fridge) = 461 mbar, Main bath = 32.5% |
| 1430 | MC(Cernox)/Sorb/1K Pot = 16.5/5.9/4.7 K, IVC = 6.3 μbar, G1(fridge) = 457 mbar, Main bath = 47.8%. DIB1 qIbias-QET D = 25.33 nS |
| 1445 | MC(Cernox)/Sorb/1K Pot = 12.0/5.6/4.5 K, IVC = 2.2 μbar, G1(fridge) = 453 mbar, Main bath = 63.7%. |
| 1450 | MC(Cernox) = 11.0 K, IVC = 1.9 μbar, that's pretty low. Start pumping IVC with turbo pump. |
| 1500 | MC(Cernox)/Sorb/1K Pot = 7.1/5.7/4.5 K, G1(fridge) = 447 mbar, Main bath = 77.0%. |
| 1512 | End LHe transfer @ MB = 81.0% |
| 1500 | MC(Cernox)/Sorb/1K Pot = 6.9/6.1/4.8 K, G1(fridge) = 489 mbar |
| 1525 | Tower = 7.03 K, DIB1 qIbias-QET D = 25.27 nS |
| 1541 | Tower = 6.83 K, DIB1 qIbias-QET D = 25.04 nS |
| 1605 | Tower = 6.41 K, DIB1 qIbias-QET D = 24.82 nS |
| 1620 | Tower = 6.09 K, DIB1 qIbias-QET D = 24.63 nS |
| 1700 | Tower = 5.57 K, DIB1 qIbias-QET D = 21.60 nS |
| 1722 | Tower = 5.44 K, DIB1 qIbias-QET D = 19.81 nS |
| 1730 | Fill LN2 cold trap bath |