| 1040 | G1/G2/P1 = 2.6 / 653 / 1.3 mbar; MC = 16.7K. Pump fridge contents to dump. |
| 1105 | Fill cold trap. G1/G2/P1 = 1 / 653 / 0.015 mbar; Commence circulation. 1KPot = 1.7 K |
| 1210 | V12A fully open. G1/G2/P1 = 135 / 164 / 1000 mbar; MC = 2.33 K |
| 1217 | Start circulating. MC = 2.1 K; G1 = G2 ~= 82 mbar |
| 1420 | Close V14. MC = 385 mK and stable |
| 1430 | MC = 385 mK; 1KPot = 1.801 K; G1/G2/P1/P2 = 142 / 136 / 0.240 / 110 mbar |
| 1433 | Commence 1-shot. Goal: continue until dump reaches 60 mbar (which should reduce 3He fraction to 17%), then recirculate with remainder in fridge lines |
| 1443 | NOTE: computer time is off. So logged file times are 12 min. earlier than actual time. Times in this note are actual time. |
| 1445 | checking still temp (note there will be a jump in logged file). MC = 1 K, Still = 0.65 K |
| 1453 | check still temp again. MC = 1.4 K, Still = 0.61 K / 0.024 mbar(P1) |
| 1453 | G2 = 50 mbar, but closing V6 to 20% seemed to make it jump to 82.7 mbar. So more removed than intended. |
| 1454 | closed V9, opened V13A (restarting circulation) |
| 1507 | Open V6 to 100% |
| 1525 | fridge stabilizes, MC = 1.03 K, Still = 0.200 mbar |
| 1530 | Close V6 in prep for measuring dump pressure on G1. Close V1 and V12A+speedivalve. Open V5 to pump out G1, close V5. Open V4: Dump pressure = 99.3 mbar. So yes, removed too much (3He fraction only about 11.5%). Pump dump to trap until dump = 63.1 mbar. |
| 1545 | Recommence condensation. |
| 1550 | Commence circulation. |
| 1612 | V6 open to 100% |
| 1613 | MC = 820 mK, checking still temp: Still = 1.01 K / 0.280 mbar |
| 1630 | MC stagnates at 750 mK. Open V14 to add rest o' mix |
| 1700 | Close V14. MC = 386 mK. G1/G2/P1 = 148 / 143 / 0.260 mbar. Still = 810 mK, 1KPot = 1.803 K |
| 1720 | Commence one-shot |
| 1735 | When Still reaches 650 mK close V9 and open V13A to recommence circulation. Still temperature rises. |
| 1756 | Was logging Still temp - switched to MC to check. MC = 745 mK, Still = 1.02 K, 0.260 mbar |
| 1800 | Stop circulation. PREP TO ADD NEW 4He TO DUMP. Close V6, V1, V13a. Pump trap contents to dump through 12a, 5, 9 |
| | Attach hose from He cylinder to Vent port. Stop pumping 1KPot briefly to use pump to evacuate hose. |
| | G2 (dump) = 59 mbar. Goal: add 47 mbar 4He, so final value of 106 mbar at G2. (This should increase mixture amount from 653 mbar (25%) to 700 mbar (23%). Fairly conservative.) |
| | G1 (trap) at 2.2 mbar. Let some 4He in to fill manifold between V7 and V11a. Then let this into trap. G1 → 3.3 mbar. |
| | Repeat until G1 = 12.6 mbar (10.4 mbar added to trap). Now pump to dump. G2 rises 58.2 → 59.2 mbar |
| | Let more 4He into trap. G1 → 63.5 mbar. Pump to dump. G2 → 61.5 mbar. |
| | Let more 4He into trap. G1 → 308 mbar. Pump to dump. G2 → 79 mbar. |
| | Let more 4He into trap. G1 → 335 mbar. Pump to dump. G2 → 101 mbar. |
| | So in total, ADDED 42 mbar OF 4He TO DUMP |
| | Note: twice we let more 4He into the trap than intended, and so pumped it back out with pot pump to get back to the amount we wanted. One must be quite careful to not remove any mixture. At one time G2 looked like it may have been decreasing a little during this pumpout - concerning. |
| 1845 | MC = 1.66 K |
| 1846 | start LHe transfer to bath @ 9.6% |
| 1849 | stop 1Kpot, turn on MC heater to 10 mW to recover mixture from fridge to dump for the night. |
| 1930 | Cease LHe transfer (90.6%). |
| 2025 | G1=0.7 mbar, G2=699.3 mbar, P1=10 ubar, Mixing chamber temperature at 11.6 K, and 1K Pot at 3.48 K. Turn off mixing chamber heater, close gate and condenser line speedivalve. Close all valves on IGH. |