2022/08/15 (Monday)
- Lab in-personnel: Giulia, Matt
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1), DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) Lead/poly shield fully assembled. Boron-filled socks covering NaI detectors. PuBe behind lead wall on West side of lead/poly shield. |
| 1100 | MC/Coldplate = 28.7/150 mK, Still = 1.13 K / 0.120 mbar / 0 mW, G1/G2 = 163/151 mbar, 1K Pot = 50° / 1.62 K / 20±2 mbar, MB = 55.5% |
| 1111 | Fill LN2 cold trap bath |
| 1500 | All channels showing pulses, baselines near -0.8 V still, EXCEPT DCRC1pB. Redoing IbIs on that one. |
| 1515 | Perform IbIs on DCRC1pB. Found a new value for QET bias to set dP/dI to 1.0 uV: 224.0 uA. This has changed a lot from what I got on Friday: that was 244.0 uA. |
| 1535 | Check IbIs on DCRC1pA. This one also changed. For 1.0 uV, previous QET bias 246.7 uA, new 225.3 uA. Both of these suggest that he detector is warmer than on Friday. |
| 1547 | Begin LHe transfer @ MB = 22.9% |
| 1635 | End LHe transfer @ MB = 95.6% |
| 1715 | Check IbIs on DCRC1pD. This one also changed. For 1.0 uV, previous QET bias 295.1 uA, new 277.7 uA. |
| Note: today MC temperature reads 28.7 mK. Friday it read 28.3 mK. So this is consistent… but the effect is pretty strong (unfortunately) | |
| 1735 | Check IbIs on DCRC3pA. This one also changed. For 1.0 uV, previous QET bias 242.4 uA, new 229.3 uA. |
| 1750 | Check IbIs on DCRC3pB. This one is different, it's a bit higher now. For 1.0 uV, previous QET bias 212.5 uA, new 221.0 uA. |
| 1800 | Check IbIs on DCRC3pD. Also a bit higher now. For 1.0 uV, previous QET bias 242 uA, new 247.8 uA. |
| 1800 | Note - MC temperature has gone down since transfer, compared to before transfer. It's now 28.5 mK. It could be that the QETs are really sensitive to these changes, so the last two channels need higher QET biases compared to the previous… |
| 1810 | DAMMIT. Enabled DCRC2 so I could set the bias. Then HV shot up to like 700 V or something, and MC temperature shot up to above 40 mK. That's because THE ODB DCRC VERSION WAS RESET TO 3.1 INSTEAD OF 3.0. I guess the f'in SQUIDtuningGUI reset it, maybe because this weekend I was messing with the SQUID tuning functions. Crap. |
| dialed HV down to zero on the Kepco itself, then unplugged HV cable from HV box | |
| 1820 | MC cooled to 35.7 mK but now it's rising again, a little. Peaked, then cooling again… |
| 1820 | MC peaked again… unplug DCRC1&3, in case SQUIDs are messed up and heating things |
| 1825 | Fridge is cooling |
| 1830 | Recalibrate HV. DCRC2qI=0 → HV = 300V, DCRC2qI=11.59 → HV =~ 0V |
| 1830 | MC = 33.5 mK and cooling |
| 1835 | Repower DCRCs1&3, turn on DAQ programs, zap SQUIDs |
| 1845 | Phonon channels all showing pulses again - good! Didn't completely fry anything |
| 1845 | MC = 30.7 mK, cooling slowly |