2016/08/01 (Monday)
| Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3), Tower has been cooled below Al transition with mu-metal shield at standard position | |
| 0805 | Tower/MC/Coldplate = 57.1/30.7/161 mK, Still = 1.39 / 0.075 mbar, G1/G2 = 210/195 mbar, 1K Pot = 1.55 K / 5.5 mbar, MB = 68.9% Boiloff rate is good so yesterday's pressure releases worked: one 10 min after fill, one 30 min after fill |
| Tower temperature has been rising slowly overnight, no other obvious cryo problems. Looks like MC and CP are elevated too, maybe also Still (but it's pressure is normal, and the thermometer sometimes just read high) | |
| 0810 | Tweak 1K Pot needle valve open a few more degrees |
| 0815 | Fill LN2 cold trap bath |
| IVC pressure is I think a little higher than it has been, at 10 nbar. Maybe He buildup in the IVC is one reason the temperature is going up. | |
| 0820 | Start pumping IVC with turbo pump |
| 0853 | Small spike in Tower temperature then falls to somewhat lower, 53-54 mK. Don't know why. Later: it hit a minimum at 9:40 but then started creeping up again toward this morning's base |
| 1030 | Turbo = 1.6 nbar while pumping IVC. Close valve @ turbo pump: after a few minutes IVC = 8.6 nbar. Not surprising it didn't go down much with tower at base. |
| 1215 | Tower is up to 55.1 mK |
| 1315 | Tower is up to 56.6 mK. IVC is back up to 10 nbar. |
| 1700 | Top off LN2 cold trap before switching circulation from Cold Trap 1 to Cold Trap 2. |
| 1705 | Tower temperature: 59.9 mK. P1: 75ubar, G1/G2: 202/188 mbar. 1K Pot: 1.58K / 7.0mbar. |
| 1710 | Open V13B to let mixture into Cold Trap 2. Close V13A and open V12B and Cold Trap 2 speedivalve to begin circulating through cold trap 2. Close V12A and Cold Trap 1 speedivalve. Mixture is still present in Cold Trap 1. Open V11A and V8 to let it back into circulation. |
| 1713 | While letting the remaining mixture from Cold Trap 1 back into circulation, Tower temperature rises to 77mK then begins oscillating. G1/G2 have reached 204/188 mbar and stabilized. P1 rose to 340mbar before falling rapidly. Currently P1 is at 0.70mbar. |
| 1725 | Tower temperature back down to 60.2mK. P1: 0.12mbar and still dropping. G1/G2: 207/184mbar. 1K Pot: 1.58K / 7.0mbar. I suspect cleaning the He cold trap will be in order, but will have to wait until the LN2 Cold Trap 1 has had all the mixture pumped out of it. |
| 1755 | Tower temperature at 61mK and continuing to increase slowly. P1 has been at 0.10mbar for about 10 minutes now. Will leave V8/V11A open a bit longer to ensure we get all the mix out of cold trap 1. |
| 1815 | Close V11A and V8. P1=0.1mbar. |
| 1820 | MB = 54.7% |