2021/07/21 (Wednesday)
- Lab in-personnel: Pramod and 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. | |
| 1124 | Tower/MC/Coldplate = 93.7/35/192 mK, Still = 1.42 K / 0.08 mbar / 0 mW, G1/G2= 292/262.7 mbar, 1K Pot = 1.62 K / 20±1 mbar. MB = 30.5%. |
| 1127 | Fill LN2 cold trap bath. |
| 1240 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 1.6/1.17/1.53/7.5 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 16/2/3.3/29 e-6 |
| These are more lower than yesterday. | |
| 1315 | Place Na-22 source 50 cm East of detector (center-to-center distance) on stand in lead castle. |
| 1319 | Start 45 min series of 0V/-15V (bias applied after 60 sec), with Na-22 source at 0.50 m, with 1000 beginning randoms, trigger threshold 60/55/40/70 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. |
| 1407 | Dial bias down to 0V and flash detector for 60 seconds |
| 1425 | Increase ChargeWaveFormLength in DCRC1&3 from 8192→65536. This will increase the trace length from 1.6384 ms to 13.1072 ms. |
| 1430 | Apply -15V bias to Side 2. Now we are seeing some pulses. |
| 1435 | Event rate in DCRC1qI(q4) for pulses above 0.1V: 91 pulses counted in 200 traces. 34.7 Hz. |
| 1440 | Event rate in DCRC3qO(q1) for pulses above 0.1V: 87 pulses counted in 200 traces. 33.2 Hz. |
| 1440 | Dial bias down to 0V and flash detector for 60 seconds |
| 1440 | Restore ChargeWaveFormLength to standard settings. |
| 1440 | Put Na-22 source back in safe |
| 1548 | Begin LHe transfer @ MB = 23.2% |
| 1625 | End LHe transfer @ MB = 89.6% |
| 1720 | Do mvNwait +4steps×8times, 35 second wait, with dwell = 40 and power = 6.8 V. (Around 6.78 mm/hour.) This should taek 4min40sec total and move 0.53 mm to put source at y = 0.00 mm. |
| Tower temperature was @ 35 mK when started to move the source and first spikes @ 0.21 K, Tower peaks @ 1.70 K, and falls down to 0.5 K after 10 min Tower maximum peak |
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| Generally the impact ionization pattern increases as Na-22 source is brought closer except for the closest distance |