2021/09/17 (Friday)
- Lab in-personnel: Giulia and Matt
| Status | Run 74 in progress. First cooldown after IVC rebuild. |
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| Tower thermometer is reading high, probably this is a thermometer problem and the actual temperature is much lower. High noise in some of the charge channels. | |
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/ |
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| Position of Am source: y = 0.0 mm | |
| Circulation is suspended so we can explore data at higher temperatures. 1K Pot is still on. MC heater left on overnight at 18 mW | |
| 1009 | Tower/MC/Coldplate = 2291/2695/4039 mK, Still = 2.94 K / 1000.0 mbar / 0 mW, G1/G2= 71.300/59.800 mbar, 1K Pot = 1.56 K / 10±1 mbar. MB = 75.2%. |
| 1015 | Fill LN2 cold trap bath |
| 1018 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 7.5/2.3/2.6/63 8e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 120/8.2/12/350 e-6. |
| Noise is slightly higher than yesterday especially @10kHz, while some are slightly lower @3khz. | |
| 1045 | Tower = 2.29 K |
| 1049 | Start 45 min series of +10/0V data (bias applied after 60 sec), at elevated temperature, with 1000 beginning randoms, trigger threshold 50/25/30/180 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. |
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| 07210917_1049 |
| 1128 | There was a partial MIDAS crash during the series. I restarted MIDAS and in the process turned off the DAQ programs. When I turned them back on the sequence continued, so maybe there will be a gap in the data - hopefully the data is still coming in now. |
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| Looks like only 37 dumps. Although there are data files in /livedata left over - looks like the lazylogger isn't copying them over to /byseries. Maybe I can try to do that manually… | |
| 1135 | Tower = 2.29 K |
| 1213 | Start 45 min series of -10/0V data (bias applied after 60 sec), at elevated temperature, with 1000 beginning randoms, trigger threshold 50/25/25/180 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. |
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| 07210917_1213 |
| 1300 | Tower = 2.29 K |
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| 1325 | Turn off MC heater. Planning to cool back to base for a few more measurements. |
| 1530 | Tower/MC = 1.68/1.92 K. G1/G2 = 42/32 mbar. Tower temperature is basically flat, G1/G2 have been falling steadily. |
| We'll start circulation as usual. The only difference is we haven't let any mixture into the dump, so we're starting off with all mixture in the circulation lines. Not sure whether that will make the pressures go higher then usual as we cool toward base. | |
| 1535 | Turn on 3He pump. G1/G2 → 47/27 mbar. |
| Referring back to June 11, the last cooldown | |
| 1540 | Start circulation through Trap 2. V6 → 12.4%. (Not sure if this is enough to open it yet, last time nothing changed till we opened to 12.8%.) |
| V6=12.4% is definitely enough: Fridge pressures rising, MC temperature falling Condenser(G1) peaks at 104 mbar |
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| 1555 | V6 → 12.8%. Condenser peaks @ 178 mbar. MC → 1.79 K |
| 1558 | Start LHe transfer @ MB = 32.4% |
| 1620 | V6 → 13.2%. Condenser peaks @ 368 mbar. Still → 38 mbar. MC → 1.63 K |
| 1633 | End LHe transfer @ MB = 91.4% |
| 1650 | V6 → 13.6%. MC zigzags between 1.55-1.67 K, not sure what transition it's going through. Condenser starts to plateau but then rises more when the MC zags up… |
| 1700 | Condenser = 580 mbar, Still = 22 mbar. Condenser may not have peaked but I'll push V6 again anyway. |
| 1700 | V6 → 14.0%. Looks like we powered through the transition: MC → 1.4 K and falling fast. Condenser peaks @ 658 mbar. Still → 3.4 mbar. |
| 1710 | V6 → 14.4%. Condenser doesn't rise, → 440 mbar and falling. Still → 0.9 mbar. MC = 1.14 K, kinda flat. |
| 1715 | V6 → 15.0%. Condenser doesn't rise, → 410 mbar and falling. Still → 0.6 mbar. MC → 1.12 K. |
| 1720 | V6 → 100%. Condenser doesn't rise much, → 418 mbar, flat-ish. Still → 0.16 mbar. MC → 0.82 K. Tower = 0.85 K |