2019/03/24 (Sunday)
| 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 → DCRCX(4)/DCRC50(3) DCRC33(2) → 1kV power supply → HV input Lead poly shield is erected, N/E/W walls complete, no poly or lead on S wall. PuBe source present in paraffin barrel behind lead stack. |
|---|---|
| 1240 | As I suspected, MIDAS is down. Kill then restart MIDAS and DAQ programs. Sequence restarts with voltage rampup. Stop sequence. Adjust DCRC2qI bias to dial HV to 0 V. |
| 1250 | Check the phonon channels. Surprisingly all look OK, even though Tower temperature went up a bit yesterday. |
| 1255 | Tower/MC/Coldplate = 43.5/31.5/199 mK, Still = 1.85±0.20 K / 0.150 mbar, G1/G2 = 258/237 mbar, 1K Pot = 1.79 K / 15 mbar. MB = 34.1% |
| 1300 | Fill LN2 cold trap bath |
| 1325 | Begin LHe transfer @ MB = 33.6% |
| 1358 | End LHe transfer @ MB = 89.5% |
| 1420 | Since MIDAS crashed after 2 series, try generating a new sequence that's only 2 series. Also did a new HV calibration so it will get closer to 0 V. |
| 1430 | One channel railed after transfer, so take all channels down to 0 uA QET bias, then up to 800, then down to previous values. All show OK pulses, Tower temperature is falling from 45.5 mK. |
| 1433 | Start 2 PuBe series at HV = 300→400V @ 5.4 V/min (18 min duration) with 1 minute 15% prebias CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (410/370/430)/(430/390/420) uA, Front-End Gains = (4/2/3)/(10/15/10) 1000 BOR randoms, trigger on DCRC3pB/D threshold = 7/7 use sequence HVdrift_fast_2X300V_5p4VPM_prebias_15_1_dur_18min.msl |
| 1440 | HV = 343.7 V, Vtest = 100 mV. This is the prebias. Vtest maxed at 150 mV during rampup. |
| 1441 | Data started. All channels are OK (some jagged noise seen but otherwise normal). |
| The two series completed and the channels seemed to stay good, according to BatViewer (also Tower temperature has not risen). But the leakage was higher on the second series. On the first series it went from 50 to 150 mV during the 300→400 V HV drift; on the second series it went from 50 to 250 mV. | |
| It looks like MIDAS crashed again. Stop and restart MIDAS and DAQ programs. The sequence finished either before the crash or within a few minutes of the restart. | |
| Because of the increased leakage I won't start more data remotely. We should try purging the Ebox with N2 to see if that helps. It's getting warmer so it's probably not as dry in the lab as it has been. |