2021/02/25 (Thursday)
- Lab in-person: Ruiren
- Virtual partner: Matt
| Status | Run 74 in progress. |
|---|---|
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/motor_board+HV_board → DCRC50(3)/55(1). No lead/poly shield. | |
| 0745 | Start a run and view channels with Pulse Viewer, set bias to 5V, and try setting triggers on each channel individually. All seem to work ok with thresholds of 100 or 150. All seem to have primarily upright pulses. Yesterday DCRC3qI seemed to need 4600 thresh to avoid overtriggering, but that's not the case today. |
| 0905 | MB = 24.0% |
| 1005 | Write a sequence r74_takeandflash_dcrcbias.msl. This sequence asks for bias voltage, duration, and number of multiple series. It starts a series, waits 1 min, then applies bias (DCRC biasing). So the biased data starts after the randoms. At the end it flashes the detector for 30 seconds. Note that trigger thresholds and LED settings should be set beforehand. Sequence will automatically turn on Write Data then turn it off again. |
| 1015 | Start 31min series of 7V data (bias applied after 1 min), with 1000 beginning randoms, trigger threshold 100/100/100/100 on DCRC3qI/qO/DCRC1qI/qO, no in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use sequence r74_takeandflash_dcrcbias.msl |
| 1025 | After triggering started, it was clear that the thresholds were too low, so I started turning off triggering and adjusting thresholds, then turning it back on. 13 minutes into the run I settled on DCRC3qI/qO/DCRC1qI/qO = 300/200/600/600 and turned on all 4 triggers. |
| 1030 | 16 minutes into the series I adjusted thresholds to DCRC3qI/qO/DCRC1qI/qO = 300/200/300/300 |
| 1105 | MB = 20.3% |
| 1306 | MB = 17.0% |
| It took about 90 minutes for Tower to cool all the way to base after the flash. Although 60 minutes might be OK. It was about 2 mK above base after 60 minutes. | |
| 1310 | Tower = 99.2 mK |
| Let's try that 7V sequence again with the adjusted trigger settings. | |
| 1312 | Start 31min series of 7V data (bias applied after 1 min), with 1000 beginning randoms, trigger threshold 300/200/300/300 on DCRC3qI/qO/DCRC1qI/qO, no in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use sequence r74_takeandflash_dcrcbias.msl |
| Triggering looks OK | |
| It looks like these thresholds may not be low enough to see the 60keV peak clearly. It would be good to get the noise lower, it's higher than in Run 67. | |
| 1406 | MB = 15.3% |
| 1508 | Ruiren in lab |
| 1515 | fill LN2 cold trap bath |
| 1515 | Tower/MC/Coldplate = 99/35.8/133 mK, Still = 1.49 K / 0.130 mbar / 0 mW, G1/G2= 164/145 mbar, 1K Pot = 1.67 K / 36±2 mbar. |
| 1545 | started lHe transfer. Bath at 13.1% |
| 1645 | finished lHe transfer. Bath at 90.8% |
| Had some trouble with the extender to the transfer line, seems like the tightener was loosened too much, allowing cold helium to squirt out of the joint and freezing the o-ring so that it was impossible to collapse the extender. It took a long time to remove the stick and we lost a fair amount of helium from the Dewar in the process. | |
| 1648 | Ruiren leaves lab |