2021/09/02 (Thursday)
- Lab in-personnel: Matt and Giulia
| Status | Run 74 in progress. First cooldown after 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. Lead shield erected, 4 walls. Currently both DCRCs are on. | |
| Position of Am source: y = 0.0 mm | |
| 0953 | Tower/MC/Coldplate = 138.1/35.0/192.4 mK, Still = 1.39 K / 0.070 mbar / 0 mW, G1/G2= 284.3/257.2 mbar, 1K Pot = 1.56 K / 10±1 mbar. MB = 74.9%. |
| 1010 | Fill LN2 cold trap bath. |
| 0942 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 28/5.0/5.3/85 8e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 510/40/56/600 e-6 |
| Noise is pretty much the same as yesterday. | |
| 1021 | Start 45 min series of 10V/0V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 80/40/40/120 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. |
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| 07210902_1021 |
| 1215 | Turn on MC heater → 800 uW |
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| 1300 | Tower/MC = 1.02/1.11 K. Temperature seems to have settled. |
| 1315 | Tried to start a series but something went wrong - got some errors saying DCRCdriver wasn't responding quickly enough, then when the bias was applied I saw breakdown noise. Then at some point the DCRCdriver program crashed. After restarting the programs things looked fine. But the bias was applied, so we need to flash before trying again. |
| 1325 | Set biases to 0V then flash DCRC1&3 LEDs for 100 seconds. |
| 1351 | Start 45 min series of 10V/0V (bias applied after 60 sec), at elevated temperature, with 1000 beginning randoms, trigger threshold 100/50/40/300 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. |
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| 07210902_1351. Tower = 1.02 K. Again we see somewhat stronger impact ionization |
| 1455 | G1/G2 = 400/364 mbar, Still = 0.13 mbar |
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| 1455 | Turn off MC heater |
| 1645 | Tower/MC = 152/36.4 mK |
| 1647 | Start 45 min series of 10V/0V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 100/40/70/350 on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Use Sequencer script r74_takeandflash_dcrcbias.msl. This flashes for 30 seconds at end of series. |
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| 07210902_1647. So this time we saw a slight increase in impact ionization strength at elevated temperature, and a return when cooled back to base. |