2016/07/28 (Thursday)
| Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3), Tower has been cooled below Al transition with mu-metal shield at standard position | |
| DCRCs on overnight. Baked detector for 15 hours last night. Tower temperature held at 0.4 K then fell at 6:07. | |
| 0850 | Tower/MC/Coldplate = 41.5/36.9/165 mK, Still = 1.43 K / 0.080 mbar, G1/G2 = 210/195 mbar, 1K Pot = 1.55 K / 5.0 mbar, MB = 40.5% Boiloff rate good |
| 0855 | Fill LN2 cold trap bath. |
| Yesterday the DAQ was used to look at HPGe pulses. Probably this means that the timing link is screwed up. So timing link commands should be redone in the Telnet sessions. | |
| 0910 | Reset timing link via Telnet commands |
| 0912 | Start 30min background series at -4/+4 V with FG=5/2/5, OG=8/3/8, with 1000 initial randoms, 1000 ending randoms, with 30s flash and 25 minute cooldown between series. Trigger on DIB1 phA with threshold of 30ADC bins, with 150 us pileup cut window. |
| 1100 | All phonon channels still alive and well. Start 30min background series at -6/+6 V with FG=5/2/5, OG=8/3/8, with 1000 initial randoms, 1000 ending randoms, with 30s flash and 25 minute cooldown between series. Trigger on DIB1 phA with threshold of 30ADC bins, with 150 us pileup cut window. |
| 1205 | All phonon channels still alive and well. Start 30min background series at -2/+2 V with FG=5/2/5, OG=8/3/8, with 1000 initial randoms, 1000 ending randoms, with 30s flash and 25 minute cooldown between series. Trigger on DIB1 phA with threshold of 30ADC bins, with 150 us pileup cut window. |
| 1425 | Over the past 30 minutes the tower temperature increased from 42.8mK to 43.2mK. It's unclear why. Check the phonon channels again. |
| 1430 | Tweak open 1K Pot to see if that lowers the rising base temperature. In the meantime, no adjustment to QET bias brought pulses back to the phonon channels. Relocking the SQUIDs does nothing. Adjusting the Frontend Gain down to 1 and back up to 5 several times will occasionally give the appearance of some kind of pulse-like disturbance, but nothing concrete. Perhaps a DCRC restart. It will have to wait until we finish cooling post-1K Pot-tweak, to see if we _do_ get a lower base temperature from opening the 1K Pot needle valve. If not, the DCRCs may be responsible for both issues. |
| 1450 | Temperature only drops to ~42.8 mK before flattening and rising slightly. Will try unplugging DCRCs next. |
| This morning's data was no good because DCRCs 1 & 3 were triggering on their test signal instead of Triggering on DIB1 phA threshold of 30ADC. Change the triggers back to normal and check to see if that helps the pulses. Still no pulses. Unpower DCRCs. | |
| 1500 | With DCRCs off Tower temperature falls, had crept up to 43 mK, now falling below its former base of 41 mK |
| 1502 | Commence LHe transfer (31.2%). |
| 1515 | Repower DCRCs. Zap SQUIDs. |
| 1520 | Reestablish timing link and look at pulses. No sign of pulses. |
| 1600 | Cease LHe transfer (75.4%). |
| 1608 | Let pressure out of main bath. |
| 1622 | Still cannot see pulses. There are hints of pulses on DIB2 pA & pB, but no big pulses. Temperature of Tower creeping up as before. Unpower DCRCs and wait for tower to cool down. |
| 1730 | Fill LN2 cold trap full. |
| 1735 | Since unplugging the DCRCs, Tower temp has fallen to 37.4 mK, then jumped back up to 38.1 mK, then started dropping back to 37.0 mK. Restart DCRCs. Zap SQUIDs. |
| 1750 | Pulses visible, but lots of jagged noise, and the infrequent pulses we see are rounded with a saturated look to them. Try baking overnight. |