2020/10/30 (Friday)
- Lab in-person: Matt
- Virtual partner: Zach
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on. Lead/poly shield erected (4 lead walls, 2 poly walls). |
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| 1015 | Tower thermometer ~ 55 mK. Phonon channels have some ugly pulse shapes and pathological offsets, let's zap. |
| 1020 | Zap DCRC1&4 SQUIDs. |
| 1030 | Matt Fritts body temperature = 97.4 F |
| 1045 | Do IbIs on DCRC1pD, suggests detector temperature 63 mK, higher than it's been recently. And pulses look weak and there's some ugly noise. We'll try zapping again. |
| 1045 | Zap DCRC1&4 SQUIDs. |
| 1130 | More IbIs, now Tower thermometer reads 56-59 mK, Detector temperature ~ 61.5 mK |
| 1131 | Start a 60 min series at HV = 0V, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = automatically updated to track temperature, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pB/D threshold = 8/8 Use sequence SimpleDataLoopNoFlash.msl Use QETbias_update.c, function sequence_update_QETbiases(60,30,0,0.0832,56.764) |
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| Tower thermometer wandered between 55.2 and 57.4 mK during series, mostly dropping. |
| 1215 | Matt enters lab |
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| 1240 | Tower/MC/Coldplate = 55.2/31.2/195 mK, Still = 1.49 K / 0.120 mbar / 0 mW, G1/G2= 254/227 mbar, 1K Pot = 1.61 K / 17±2 mbar. |
| 1350 | Fill LN2 cold trap bath |
| As seen in yesterday's run diary entry, it looks like TES gain is lower in recent 0V data, and definitely fall times are shorter. The change is likely due to the source mover tests. In our earlier slow moves, we didn't see any reduction in phonon collection efficiency after source moves. But these faster moves, which heated the tower more, may have caused trapped flux in the QET fins. So: we should try a hot Al flash. | |
| We'll try the sequence Al_flash_DCRC1.msl which was written on Aug 13 | |
| 1430 | Run Al_flash_DCRC1.msl to expose detector to a hot Al flash. This is a 90-second flash with a duty cycle 5-times greater than our normal neutralization flashes. |
| Tower reached 1.5 K during flash | |
| 1510 | MB = 59.9% |
| 1510 | Matt leaves lab |
| 2220 | Did some IbIs, detector seems kind of warm according to DCRC1pD. 64.7 mK. But having trouble with DCRC4pB, it goes s/c if I try to set the QET biases appropriate for DCRC1pD. |
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| 2225 | Flash DCRC1&4 SQUIDs |