2017/03/29 (Wednesday)
| Setup: DIB1/3/4 → 3.2 MHz filters 3/1/2 → cable 3/1/2 →gender changer 3/1/2 → HVConn 1/3/2 → HV 1/2 → DCRC55/DCRC33 | |
| Fridge failure, the pump power is off. Looks like it happened some time before midnight, earlier than the LabView look-back time | |
| 0935 | Tower 1.8 K, 1K Pot 5.6 K / “1 bar” (max), G1/G2 = 355/315 mbar, Still = “1 bar” (max) |
| 0940 | Fill LN2 cold trap bath |
| 0940 | Close 1K Pot pumping valve and v4a, so that when we turn the 4He pump back on it won't be overly taxed. Turn off both pumps on IGH control. Reset pump power box in pump alley. Then turn on 4He pump. Open V4a to pump out pot pumping line. Open 1KPot speedivalve. Pot temperature falls quickly. |
| 0945 | Check MC temperature: MC = 2.0 K 1K Pot temperature and G1/G2 (condenser) pressures are falling |
| 0950 | 1K Pot = 1.8 K / 28 mbar, G1/G2 = 220/195 mbar Turn on 3He pump. Condenser pressure goes high, try to close v6 but too slow, G1 goes over 1 bar so I think some mix got diverted into the dump. |
| 0955 | With v6 closed, condenser pressure is settling, G1/G2 = 540/490 mbar and falling. |
| 1030 | 1K Pot = 1.65 K / 16 mbar, G1/G2 = 80/65 mbar. Open v6 to 13%. G1/G2 go up about 5 mbar. Open v6 to 13.5%. G1/G2 rise above 125 mbar |
| 1040 | 1K Pot = 1.69 K / 26 mbar, G1/G2 = 175/155 mbar and flat. Open v6 to 14.2%. G1/G2 rise to 295/265 mbar Still pressure begins to fall |
| 1045 | 1K Pot = 1.70 K / 32 mbar, G1/G2 = 290/260 mbar. Condenser pressure and Tower temperature falling a bit Still = 4 mbar. Open v6 to 15% |
| 1050 | MC = 1.3 K and falling G1/G2 flattish at 295/265 mbar. Open v6 to 15.8%. Still → 0.55 mbar |
| 1055 | Main bath = 35.3% |
| 1055 | Tower/MC = 1.1/1.17 K, Still = 0.6 mbar, G1/G2 = 295/265 mbar and flat Open v6 100% |
| 1115 | Tower/MC = 0.86/0.96 K, Still = 0.17 mbar, G1/G2 330/295 mbar and flat Open v14 to pull any extra mix out of dump. Let G1/G2 rise to about 600 mbar then close v14 again. Surge in Still and 1K Pot |
| 1130 | Tower/MC = 275/230 mK, Still = 0.13 mbar, G1/G2 = 355/320 mbar and slowly falling Open v14 again. Again close it after G1/G2 hit 600 mbar (takes longer this time). |
| 1145 | Tower/MC = 87/78 mK, Still = 0.12 mbar, G1/G2 = 325/295 mbar and slowly falling Open v14 again. G1 peaks at 510. Still rises then falls to 16 mbar, will leave open until Still less than 1 mbar. |
| 1210 | Tower/MC = 47/44 mK, Still = 0.9 mbar, G1/G2 = 285/255 mbar and slowly falling Close v14. |
| 1245 | Tower/MC/Coldplate = 33.7/31.3/191 mK, Still = 1.3 K / 0.120 mbar, G1/G2 = 255/230 mbar, 1K Pot = 1.706 K / 32 mbar, Main bath = 32.6%. Back to normal! Boil off rate: close to slow mode (predicted level: 30.2%). |
| 1430 | Commence LHe transfer, MB=29.5% |
| 1530 | Cease LHe transfer, MB=89.0% |
| 1734 | Fill LN2 coldtrap bath. |