2018/05/31 (Thursday)
| Setup: DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 → gender changer 3/?/2 → HVConn 1/3/2 → HV 1/2 → DCRC55(1)/DCRC50(3) | |
| DCRCs powered overnight, zero bias | |
| 0700 | Tower = 38.5 mK |
| 0945 | Tower/MC/Coldplate = 38.4/31.5/176 mK, Still = 1.16 K / 0.110 mbar, G1/G2 = 160/162 mbar, 1K Pot = 1.52±0.01 K / 6.5±0.5 mbar. MB = 70.0% |
| 0945 | MIDAS pages are unresponsive. Kill and restart MIDAS. Last sequence from last night has restarted. |
| 1019 | Start IbIs sequence on DCRC3pD, from 450 to 200 step -2 uA, HV = 0 V, front-end gain 10, driver gain 1. There were some bad files in the last sequence due to the crash, so just restarting it. |
| 1045 | Fill LN2 cold trap bath |
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Zoomed-in IbIs curves above. Some are pretty crappy. Would zapping the SQUIDs help? We neglected to do this after the last time we power cycled the DCRCs.
| 1225 | Zap SQUIDs |
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| 1253 | Start IbIs sequence on DCRC3pD, from 450 to 200 step -2 uA, HV = 0 V, front-end gain 10, driver gain 1. |
| 1330 | The IbIs results for DCRC3pD are much improved after zapping. Let's redo DCRC3pC as well. |
| 1330 | Start IbIs sequence on DCRC3pC, from 450 to 200 step -2 uA, HV = 0 V, front-end gain 10, driver gain 1. |
| this sequence was mostly railed, should have adjusted things after the zap. Try again. | |
| 1409 | Start IbIs sequence on DCRC3pC, from 450 to 200 step -2 uA, HV = 0 V, front-end gain 10, driver gain 1. |
| The IbIs results are much better on this one too | |
| 1445 | Try dialing HV bias up to 100V, reading Vtest with the Keithley 617. Vtest→252 mV and stays there. That's a hard short. But we're using the new cable, didn't expect the Keithley to short it. |
| 1445 | Try dialing HV bias up to 100V, reading Vtest with the Fluke multimeter. No short now. |
| 1450 | At Vbias=100V, Vtest is initially 150 mV then over 5 minutes falls to 94 mV. That's only 62% of the bias reaching the detector. |
| 1455 | Dial HV from 100V down to 90V. After a couple of minutes Vtest→82 mV. Still only 62% at detector. So prebiasing doesn't help much. |
| 1500 | Start N2 purge gas in e-box bag |
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| 1515 | Lab = 23.4 C, 40% humidity |
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| 1515 | Dial HV up to 100V. Leakage is lower now after purging for 15 minutes. Vtest started at 140 mV but fell to 21 mV after 5 minutes, that's 92% of the bias reaching the detector. |
| Watching DCRC1 pA, the baseline has risen significantly, by about 20 mV. It was higher when the bias was first applied, about 40 mV | |
| 1525 | Dial HV from 100 down to 90V. After 5 min Vtest settles around 14.6 mV, that's 94% at the detector. |
| 1533 | Prebias to Vbias=115 V. Jagged noise evident in phonon channel. |
| 1538 | Dial down HV, targeting Vdetector = 100V. |
| 1539 | Vbias/Vtest/Vdet = 107.3/15.5/101.1 |
| 1541 | Vbias/Vtest/Vdet = 106.3/15.8/100.0 |
| 1545 | Vbias/Vtest/Vdet = 106.3/15.8/100.0 |
| 1545 | Adjust driver offsets on all 6 channels. |
| 1545 | Start IbIs sequence on DCRC1pA, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 1610 | DAQ is stuck in middle of sequence |
| 1615 | Restart DAQ. |
| 1630 | Fill LN2 cold trap bath |
| 1640 | Start IbIs sequence on DCRC1pB, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 1741 | Start IbIs sequence on DCRC1pC, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 1745 | Vbias/Vtest/Vdet = 106.33/13.6/100.9 |
| 1817 | Start IbIs sequence on DCRC3pB, from 300 to 50 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 1854 | Start IbIs sequence on DCRC3pC, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 1940 | DAQ is stuck in middle of sequence |
| 1940 | Restart DAQ. |
| 1944 | Start IbIs sequence on DCRC3pC, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
| 2026 | Start IbIs sequence on DCRC3pD, from 450 to 200 step -2 uA, HV = 100 V, front-end gain 10, driver gain 1. |
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fridgesign.pptx fridgesign.pdf