2018/03/31 (Saturday)
| Setup: DIB1/2 → SL 43/41 → 3.2 MHz filters → cables 3/1 → DCRC50(3)/55(1). | |
| Overnight: Flash and take a set of -8V Ba series. Looks like the fridge temperature started increasing around 5:00 am. Reached a temp of around 1.3 K. | |
| 0950 | Start Sequence of 8 45 min Ba series using flashandtake_R67.msl, with DCRC bias = 6 V, with 30s flash (including initial flash), 15min cooldown, 1000 beginning randoms, and a 60/50/70/50 bin threshold trigger on DCRC1qI/qO/DCRC3qI/qO, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Good triggering. This sequence was started after the fridge failure, with the Tower above 1 K. So this is probably junk data. Or, we could call it interesting high-temperature data. Aborted at 14:33, 5 of 8 series recorded (5th one is only 23 minutes). |
| 1300 | Fill LN2 cold trap full. |
| 1306 | 1K pot pressure was very low, 1.3 mbar. Tweak needle valve a few degrees. Pressure went off scale - close it a few degrees. Settles at around 12 mbar. |
| 1312 | Stop data sequence. (actually no, it was still going) |
| 1318 | Open V14 briefly. Pressures go up, close V14, then settle. Tower = 1.01 K, G1/G2 = 360/340 mbar, P1 = 0.06 mbar, P2 = 9 mbar. |
| 1327 | Open V14 again briefly - close it. Tower = 864 mK, G1/G2 = 470/440 mbar, P1 = 0.110 mbar, P2 = 24 mbar. |
| 1330 | Start LHe transfer (MB = 32.8%) |
| 1341 | Open and close V14 |
| 1351 | Tower = 768 mK, G1/G2 = 195/178 mbar, P1 = 0.065 mbar, P2 = 12 mbar. |
| 1413 | Tower = 621 mK, G1/G2 = 113/102 mbar, P1 = 0.040 mbar, P2 = 7 mbar. |
| 1417 | End LHe transfer (MB = 91.3%) |
| 1418 | Open and close V14 |
| 1424 | Tower = 545 mK, G1/G2 = 255/236 mbar, P1 = 0.075 mbar, P2 = 5 mbar. Opening V14 doesn't seem to have much affect on P2 any more. May have to tweak the needle valve again? |
| 1430 | Stop data sequence. Then set bias to 0 V. (Not sure why the sequence didn't stop). |
| 1432 | Tweak 1K pot needle valve open a few degrees. P2 rises off scale, then down to around 50 mbar, fluctuates up again to around 300 mbar, and settles around 60 mbar. |
| 1439 | Tower = 307 mK, G1/G2 = 174/158 mbar, P1 = 0.075 mbar, P2 = 55 mbar. |
| 1453 | P2 falls to 24 mbar. Tweak 1K pot needle valve open a few degrees again and wait to settle. |
| 1500 | Tower = 162 mK, G1/G2 = 154/139 mbar, P1 = 0.065 mbar, P2 = 55 mbar. (I expect P2 to continue falling, not very rapidly but enough to be concerning. Send me a message if you need me to stop back in today. ) |
| 1916 | Tower = 57.6 mK |
| 1917 | Start Sequence of 8 45 min Ba series using flashandtake_R67.msl, with DCRC bias = 6 V, with 30s flash(including initial flash), 15min cooldown, 1000 beginning randoms, and a 60/50/70/50 bin threshold trigger on DCRC1qI/qO/DCRC3qI/qO, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Good triggering |
| 2240 | 1K Pot pressure down to 2.2 mbar, condenser 90 mbar, still 0.04 mbar - these are all very low. Open needle valve more, also open V14 until condenser rises to 500 mbar, then close again. Tower was around 80 mK, rises to 190 mK then cools again. |
| 2250 | Condenser falling, now 266 mbar. Open V14 again, leave open a while - still pressure falling as the rest of the mixture in the dump returns to circulation. Tower increases again, to 120 mK. |
| 2300 | Still down to 4 mbar. Close V14. |
| 2300 | 1K Pot down to 20 mbar. Tweak needle valve open some more. |
| 2305 | Still has fallen to 0.075 mbar, low, maybe it'll rise again. Tower 63 mK and cooling. 1K Pot 45 mbar and settling. |