2021/07/16 (Friday)
- Lab in-personnel: Matt
| Status | Run 74 in progress. First cooldown after IVC rebuild. |
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| 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. | |
| 1105 | Tower/MC/Coldplate = 86.7/35.0/171 mK, Still = 1.10 K / 0.075 mbar / 0 mW, G1/G2= 302/275 mbar, 1K Pot = 1.63 K / 20±1 mbar. MB = 66.5% |
| 1110 | Fill LN2 cold trap bath. |
| 1110 | Do mv -32 with dwell = 40 and power = 6.8 V. This should move source back to the center, y = 0.00 mm. |
| 1120 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 2.0/1.2/1.4/4.9 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 19/3.2/2.4/32 e-6 |
| This is much lower noise than yesterday, the 3kHz oscillations are down by a factor of 50. Like last week. | |
| Set things up to measure event rate. We'll increase the trace length then we'll apply bias and count pulses. | |
| 1135 | Increase ChargeWaveFormLength in DCRC1&3 from 8192→65536. This will increase the trace length from 1.6384 ms to 13.1072 ms. |
| 1140 | Apply -15V bias to Side 2. Now we are seeing some pulses. |
| 1145 | Event rate in DCRC1qI(q4) for pulses above 0.1V: 12 pulses counted in 60 traces. 15.2 Hz. |
| 1150 | Event rate in DCRC3qO(q1) for pulses above 0.1V: 4 pulses counted in 60 traces. 5.1 Hz. |
| 1155 | Assemble a stand and a lead castle for external sources. Source will be at the same vertical level as the detector (no - actually about 8cm lower than detector level), with opening in the castle toward the detector (source is N of detector). Mark spots on floor at 20cm intervals for distance placement. |
| 1215 | Dial bias down to 0V Flash the detector for 60 sec. |
| 1340 | Apply -15V bias to Side 2. Seeing pulses again. |
| 1350 | Place Ba-133 source 1.40 m, 1.0 m, 0.6 m from the center of the detector. Count pulses in 60 traces in each case: 11,5,9. So no increase in rate, this is not close enough. |
| Waiting for a change at IT, computers down. Dial bias to 0V. | |
| 1530 | Flash detector for 60 seconds. |
| 1535 | Place Ba-133 source 0.40 m from center of detector |
| 1540 | Adjust height of source stand, now source is at nearly same level as detector. |
| 1545 | Apply -15V bias to Side 2. |
| 1550 | Event rate in DCRC1qI(q4) for pulses above 0.1V: 34 pulses counted in 120 traces. 21.6 Hz. |
| 1555 | Event rate in DCRC3qO(q1) for pulses above 0.1V: 45 pulses counted in 120 traces. 28.6 Hz. |
| 1600 | Put Ba-133 source back in safe |
| 1600 | Place Na-22 source 0.40 m from center of detector |
| 1605 | Event rate in DCRC3qO(q1) for pulses above 0.1V: 53 pulses counted in 120 traces. 33.7 Hz. |
| 1610 | Event rate in DCRC1qI(q4) for pulses above 0.1V: 31 pulses counted in 120 traces. 19.7 Hz. |
| 1610 | Dial bias down to 0V and flash detector for 60 seconds |
| 1610 | Restore ChargeWaveFormLength to standard settings. |
| 1646 | Start series but having trouble with triggering, abort. |
| 1700 | Start series but having trouble with triggering, abort. |
| 1711 | Start series but having trouble with triggering, abort. |
| 1718 | Start 45 min series of 0V/-15V (bias applied after 60 sec), with Na-22 source at 0.40 m, with 1000 beginning randoms, trigger threshold 120/90/40/70 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. |
| oops - DCRC1 triggers were left off for this series. |
| 1807 | Dial bias down to 0V and flash detector for 60 seconds. |
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