2018/05/08 (Tuesday)
| Status: Cooling with 1K pot. | |
| Overnight: MC(Cernox) flattened out to ~3.9 K | |
| 0815 | MC(Cernox) = 3.92 K, Fridge(G1) = 530 mbar, 1K Pot = 3.70 K / 40.0 mbar. |
| 0820 | Fill LN2 cold trap bath |
| 0840 | Open 1K Pot needle valve a few more degrees. → 3.82 K / “1000” mbar. Close it a few degrees, falls as low as 3.45 K then rises again. |
| 0850 | 1K Pot = 3.69 K / 36.0 mbar. |
| 0855 | Main bath = 68.7% |
| temperature seems really stuck around 4K. I don't think there's He in the IVC (last time that happened the pot kept draining - pattern is different this time). Is there a touch somewhere? | |
| 0900 | Tower/MC(Cernox)/Coldplate/Still = 3.92/3.93/7.34/4.72 K, Fridge (G1) = 526 mbar |
| tried banging the main bath a couple times, in case the stripline heatsink buckle is touching the 100mK can, try to knock it loose. Banging tends to cause MC temperature to rise a little. | |
| 1000 | Monitor Cold Plate temperature then bump fridge from west side. Causes a spike in temperature from 7.63 to 7.71 K then down to about 7.66 K. |
| 1010 | Monitor Cold Plate temperature then bump fridge from east side. Causes a rise in temperature from 7.66 to 7.74 K. |
| 1030 | Turbo on IVC = 1.6 nbar. Stop pumping IVC. IVC = 14 nbar. |
| 1040 | Close 1K Pot speedivalve, no longer pumping on 1K Pot. Open needle valve a little. 1K Pot 3.64→3.83 K and rising |
| 1100 | MC(Cernox) = 3.94 K, 1K Pot = 4.15 K, IVC = 16 nbar |
| 1100 | Turn on MC heater and Still heater, both to 20 mW |
| 1110 | MC(Cernox) = 7.00 K and rising. IVC = 16 nbar |
| 1120 | MC(Cernox) = 8.82 K and rising. IVC = 16 nbar. IVC pressure not rising, suggests there's no He in it. |
| 1120 | Tower/MC(Cernox)/Coldplate/Still = 9.09/8.98/14.9/12.9 K, Fridge (G1) = 551 mbar |
| 1135 | MC(Cernox) = 10.35 K and rising. IVC = 16 nbar |
| 1135 | Turn off MC and Still heaters. MC temperature starts to fall. |
| 1155 | Try running 1K Pot again (with scroll pump since pressure is high). Doesn't get any colder than 3.2 K. |
| 1200 | MC(Cernox) = 9.73 K. It's falling slowly since turning off the heater. 1K Pot didn't seem to speed up the cooling. |
| 1220 | MC(Cernox) = 9.33 K, Fridge(G1) = 540 mbar, 1K Pot = 3.67 K / 200 mbar. |
| 1220 | Close 1K Pot needle valve completely |
| 1235 | MC(Cernox) = 8.93 K, Fridge(G1) = 500 mbar, 1K Pot = 2.92 K / 2.4 mbar. Begin opening needle valve in stages |
| 1305 | MC(Cernox) = 6.63 K, Fridge(G1) = 517 mbar, 1K Pot = 3.46 K / 17 mbar. |
| MC temperature is flattening out. Basically the same behavior as before. | |
| 1310 | Tower/MC(Cernox)/Coldplate/Still = 6.58/6.58/6.09/3.98 K, Fridge (G1) = 551 mbar |
| interestingly Coldplate and Still are both colder than they were this morning. Why is this? Maybe kicking the fridge helped a little? | |
| 1330 | Tower/MC(Cernox)/Coldplate/Still = 6.00/6.00/9.49/4.10 K, Fridge (G1) = 522 mbar, 1K Pot = 3.44 K / 14 mbar |
| strange now the Coldplate temperature is higher. Was the 13:10 measurement spurious? | |
| 1345 | Tower/MC(Cernox)/Coldplate/Still = 5.74/5.75/10.53/4.26 K, Fridge (G1) = 522 mbar, 1K Pot = 3.35 K / 7 mbar |
| 1410 | Close needle valve and speedivalve of 1K Pot. I was watching the Coldplate at the time, and for some reason closing off the 1K Pot caused the Coldplate temperature to fall. That doesn't make much sense. Fell from 9.7 to 6.2 K according to the Coldplate calibration. Interestingly the H35 calibration shows 6.4→4.3 K. So that may be more plausible. 1K Pot: 3.1→3.4 K |
| 1420 | Open 1K Pot speedivalve again. 1K Pot → 3.08 K / 3.2 mbar Coldplate temperature not rising. Was it a coincidence that it fell after messing with the pot? |
| 1445 | Tower/MC(Cernox)/Coldplate/Still = 3.40/3.41/5.95/3.93 K, Fridge (G1) = 488 mbar, 1K Pot = 3.49 K / 19 mbar |
| MC cooling rate must have increased since 13:45 and it's the coldest it's been this run, but things still seem to be lagging. Currently MC seems quite flat. | |
| 1455 | Tower/MC(Cernox)/Coldplate/Still = 3.39/3.41/5.85/3.87 K, Fridge (G1) = 488 mbar, 1K Pot = 3.50 K / 20 mbar |
| 1515 | Tower/MC(Cernox)/Coldplate/Still = 3.39/3.40/5.90/3.90 K, Fridge (G1) = 489 mbar, 1K Pot = 3.61 K / 45 mbar |
| temperatures are impressively flat. | |
| 1520 | Close needle valve and speedivalve of 1K Pot. |
| 1530 | Tower/MC(Cernox)/Coldplate/Still = 3.39/3.40/5.80/3.87 K, Fridge (G1) = 487 mbar, 1K Pot = 3.44 K and rising |
| 1530 | Turn on MC heater and Still heater, both to 20 mW |
| 1540 | MC has climbed above 5 K. Turn off heaters. |
| 1540 | Tower/MC(Cernox)/Coldplate/Still = 5.25/5.34/6.11/6.46 K, Fridge (G1) = 517 mbar, 1K Pot = 3.92 K and rising |
| 1550 | Let some He into the IVC, 16 → 30 nbar. MC temperature falls more quickly toward 4 K |
| 1600 | Let more He into the IVC, → 74 nbar. |
| 1605 | Tower/MC(Cernox)/Coldplate/Still = 4.23/4.23/7.75/5.12 K, Fridge (G1) = 529 mbar, 1K Pot = 4.24 K |
| weird behavior from the Coldplate thermometer | |
| 1610 | Fill LN2 cold trap bath |
| 1615 | Main bath = 58.9 |
| 1615 | IVC = 46 nbar |