2021/08/02 (Monday)
- Lab in-personnel: Giulia
| Status | Run 74 in progress. First cooldown aftr IVC rebuild. |
|---|---|
| Tower thermometer is reading high, probably this is a thermometer problem and the actual temperature is much lower. High noise in some of the charge channels. | |
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/Source_mover_board+HV_diverter_board → DCRC50(3)/55(1). Kepco 40V supplye → HV BNC. No lead/poly shield. Currently both DCRCs are on. | |
| 1038 | Tower/MC/Coldplate = 89.3/35/ 192.9 mK, Still = 1.41 K / 0.075 mbar / 0 mW, G1/G2= 273.2/244.4 mbar, 1K Pot = 1.60 K / 20±1 mbar. MB = 26.2 %. |
| 1050 | Fill LN2 cold trap bath. |
| 1245 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 1.8/1.2/1.4/6.8 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 19/2.5/2.5/49 e-6 |
| Noise much lower than Friday. But there are spiky glitches which prevent us from setting the thresholds very low. | |
| 1113 | Start 45 min series of 0V/-15V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 50/50/40/150 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button. |
| 1200 | Dial bias to 0V and flash detector for 10 minutes |
| 1540 | Start LHe transfer @ MB = 17.9% |
| 1621 | End LHe transfer @ MB = 88.9% |
| Today's data had another one of the things that we've seen several times - the 60keV amplitude suddenly drops to zero, then rises back up to complete the usual pattern. Not sure whether this happens due to a sudden leakage discharge which maybe drops the bias to zero… so if we can we should monitor the bias voltage. | |
| 1645 | Start data (logger off) and increase Side2 bias to -15V, view pulses. Then plug HP meter into HV leads. This does not increase noise. (Note that before we saw that plugging the Keithley into the test resistor to measure leakage does increase noise.) Start HP monitoring on Omni_Logger. Now we can monitor bias during data. (Maybe the HP could also be used to monitor current…) |
| 1650 | Dial bias to 0V and flash detector for 10 minutes |
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| 07210802_1113 |