2021/07/28 (Wednesday)
- Lab in-personnel:Pramod
| 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 supply → HV BNC. No lead/poly shield. Currently both DCRCs are on. | |
| 1055 | Tower/MC/Coldplate = 186.8/36/ 192 mK, Still = 1.40 K / 0.075 mbar / 0 mW, G1/G2= 277.8/254.6 mbar, 1K Pot = 1.62 K / 20±1 mbar. MB = 65.9%. |
| Tower temperature is lower today than yesterday. | |
| 1100 | Fill LN2 cold trap bath. |
| 1112 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 21.8/2.69/2.63/52.4 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 933/65/87/1919 e-6 |
| These are similar to yesterday. | |
| 1139 | Start 45 min series of 0V/-15V (bias applied after 90 sec), Tower @ 135 mK, with 1000 beginning randoms, trigger threshold 65/50/45/140 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. |
| 1228 | Dial bias down to 0V and flash detector for 60 seconds. |
| 1333 | Remove pi Filter, 3.2 MHz from cable 2&3. |
| 1345 | Repower DCRCs and turn on DAQ programs. Look at noise - it doesn't look much different. |
| 1347 | Start 2 min series of 0V/0V, with 1000 beginning randoms, no triggers, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button. |
| 1410 | Replace pi-filters, close up E-box purge bag |
| Looked at data from today: the impact ionization peak is around 115 keV. This is about the same as yesterday. It's lower than the day before, that was around 140 keV, after the detector seemed to go into a “metastable” state. But it's still higher than the 80 keV which was the normal condition early in this run (this particular cooldown period that is). Let's try baking the detector with the LEDs, see if it “resets” the detector. |
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| 1415 | LED settings are PulseWidth 100 us, RepRate 5000 us, current 0.6 mA. Let's increase the power for a stronger bake. |
| 1415 | Decrease LEDRepRate (us) from 5000→2000 on DCRC1&3. Actually THIS DIDN'T WORK because I used the DCRC Control Flash Tool to turn on the DCRCs, which resets to the standard RepRate=5000. (If we want to change these settings we should just turn the LEDs on and off from the ODB.) |
| 1420 | Begin 10 minute bake of detector with DCRC1&3 LEDs, with 2.5x greater duty cycle than the standard. |
| Tower peaked at 750 mK during bake. | |
| 1530 | take S104 to wirebond lab. Adjust wirebonder settings: power = 495/485, bond time = 40/30, rise/drop = 50/26 |
| 1610 | After some effort fix all channels on Side1 DIB1 |
| 1620 | Tower/MC = 116/33.8 mK. Significantly lower than before. |
| 1625 | Start 45 min series of 0V/-15V (bias applied after 60 sec), with 1000 beginning randoms, trigger threshold 65/50/45/200 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. |
| 1803 | Dial bias down to 0 V, flash detector for 10 minutes. |
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| 07210728_1139 | 07210728_1625 (after long flash) |