2018/10/02 (Tuesday)
| 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) NaI detector: 1.1 kV (for real) → NaI B/C (dynodes terminated) → Ortec 452(Neg input, gain=2.5, shaping = 6 us, output=+10V)/ Ortec 575A(Neg input, gain=5, shaping = 3 us) → x10/x10 attenuator → DCRCX(4) PB/PA DCRC33(2) → kepco 1kV power supply → HV input |
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| status: | PuBe -125V prebias scan data overnight, tower = 30.7 mK |
| 1010 | Tower/MC/Coldplate = 30.7/31.1/187 mK, Still = 0.0 mW / 1.5±0.1 K / 0.090 mbar, G1/G2 = 154/140 mbar, 1K Pot = 1.60 K / 17 mbar, Turbo on IVC = 0.74 nbar, MB = 34.9% |
| 1015 | Fill LN2 cold trap bath. |
| 1215 | Prep for IbIs. Turn off triggering. Reset all Driver Gains from 2 to 1. Then take QET biases to where IbIs is max (see May 31) and adjust driver offsets so all are near top of range. Readjust all QET biases to standard transition values. |
| 1220 | Noticed that DCRC1pB QET bias is at 280, but we've been writing down 260. Will need to check when that change occurred. |
| 1230 | Start LHe transfer (MB = 31.3%) |
| 1315 | End LHe transfer (MB = 94.1%) |
| 1330 | Dial HV up to -125V with 15%/5min prebias using change_HV_0_to_125_15-5PreBias_DCRC2_250V.msl |
Noticed that the phonon baselines all rose after applying bias:
| channel | 0V baseline [V] | -125V baseline [V] |
|---|---|---|
| DCRC1 pA | 0.655 | 0.777 |
| DCRC1 pB | 0.905 | 0.938 |
| DCRC1 pC | 0.751 | 0.775 |
| DCRC3 pB | 0.803 | 0.835 |
| DCRC3 pC | 0.127 | 0.198 |
| DCRC3 pD | 0.517 | 0.590 |
| 1405 | Start IbIs sequence on DCRC1pA, from 450 to 200 step -2 uA, HV = -125 V, front-end gain 10, driver gain 1. PuBe source present. Using IbIs_loop_DCRC1pA.msl Last time sequence took 23 minutes. |
|---|---|
| 1430 | Start IbIs sequence on DCRC1pB, from 450 to 200 step -2 uA, HV = -125 V, front-end gain 10, driver gain 1. PuBe source present. Using IbIs_loop_DCRC1pB.msl |
| 1456 | Start IbIs sequence on DCRC1pC, from 450 to 200 step -2 uA, HV = -125 V, front-end gain 10, driver gain 1. PuBe source present. Using IbIs_loop_DCRC1pC.msl |
| 1520 | Start IbIs sequence on DCRC3pB, from 300 to 50 step -2 uA, HV = -125 V, front-end gain 10, driver gain 1. PuBe source present. Using IbIs_loop_DCRC3pB.msl |
| 1544 | Start IbIs sequence on DCRC3pC, from 450 to 200 step -2 uA, HV = -125 V, front-end gain 15, driver gain 1. PuBe source present. Using IbIs_loop_DCRC3pC.msl |
| 1607 | Start IbIs sequence on DCRC3pD, from 450 to 200 step -2 uA, HV = -125 V, front-end gain 10, driver gain 1. PuBe source present. Using IbIs_loop_DCRC3pD.msl |
to return to normal after IbIs:
- set all phonon driver gains x2 (done)
- adjust driver offsets to get baselines to the usual low-ish spot
- turn triggering back on on DCRC3 phonon channels
| 1630 | Dial HV from -125V to 0V using change_HV_125_to_0_DCRC2_250V.msl |
|---|---|
| 1635 | Since transfer, tower has crept up to 31.8 mK. Maybe the SQUIDs need to be zapped again. |
| 1640 | Fill LN2 cold trap full. |
| 1643 | Trying to zap SQUIDs using DCRC_UI control tool. It keeps giving the error “problem in toolstimeout”. I think all it does though is make and run the sequence testzap.msl. Since we've zapped in this configuration before it should be right. I'll just try running that from the sequencer. That seemed to heat the tower to ~40mK like usual. |
| 1650 | Using the DCRC_UI flash tool also fails repeatedly with the same error. This is stupid. Restart MIDAS. Now it works. Flash detector for 30s. |
| 1815 | Tower is now settled at 29.5 mK |
| 1820 | Start 8x2hr PuBe series at HV = -125 V with 15% prebias for 5 min, split into 10 min subruns, with CDMS and NaI detectors running and DCRC2 as HV controller. Using sequence HVscan-125×8-15_5PreBias-DCRC2_250V-30Flash-30wait-2hrData-10minSubRun.msl CDMS detector: Driver Gains = 2x, QET biases = (280/280/305)/(140/280/295) uA, Front-End Gains = (10/10/10)/(10/15/10) NaI detector: 1.1 kV (for real) → NaI B/C (dynodes terminated) → Ortec 452(Neg input, gain=2.5, shaping = 6 us, output=+10V)/ Ortec 575A(Neg input, gain=5, shaping = 3 us) → x10/x10 attenuator → DCRCX(4) PB/PA, Driver Gains = 1/1, PhononWaveFormLength = 1024 (512 samples), PhononPrepulseSamples = 64 (64 samples) 1000 BOR randoms, trigger on DCRC3pB/C/D threshold = 7/10/9 |