2019/11/07 (Thursday)
| Setup | DIB1/2/4 → 3.2 MHz filters → cable 1/2/3 → gender changer 1/2/3 → movable source controller/board with external Feedback resistor/nothing → DCRC55(1)/DCRC33(2)/DCRC50(3) |
|---|---|
| Baked last night and took some data series. But Tower temperature is elevated, settled to 59 mK after bake, slowly cooled to around 58 mK this morning. Seems like the DCRCs are in a bad state. | |
| 0835 | Tower/MC/Coldplate = 58.3/34.4/195 mK, Still = 1.51 K/ 0.150 mbar / 0 mW, G1/G2= 78/64 mbar, 1K Pot = 1.74 K / 150±20 mbar. MB= 25.9% |
| 0840 | Take a look at the channels - seeing pulses in all phonon channels. See traces in charge channels (no pulses cuz I left the bias off). So nothing looks bad. |
| Turn off DAQ programs, I'll power down DCRCs one by one. | |
| Unplugging DCRC50(3) causes an initial temperature spike then a precipitous drop. Looks like that one was causing the heating. | |
| 0855 | Tower = 44.2 mK and continues to fall. |
| 0855 | Fill LN2 cold trap bath |
| 0920 | Tower/MC/Coldplate = 42.7/34.4/185 mK, with DCRCs off. Still cooling. |
| 0920 | Power on DCRCs and turn on DAQ programs again. First, on ODB turn off 15V Power on DCRC3, shouldn't need it. Tower spikes to 46 mK then cools again. |
| 0935 | Tower settled to 43.5 mK but it is slowly rising, now 44.0 mK |
| 0940 | Adjust 1K Pot needle valve. Accidentally opened it about 5 degrees - now closing it a little. Originally was at about 40 degrees, now about 30. |
| 0955 | 1K Pot settles at 1.71 K / 68±3 mbar |
| 1205 | Tower = 44.3 mK, slowly falling. |
| 1215 | Begin LHe transfer @ MB = 18.9% |
| 1245 | End LHe transfer @ MB = 92.3% |
| 1305 | Tower = 43.9 mK |
| 1310 | 1K Pot = 1.68 K / 42±2 mbar. It settled downward after the LHe transfer. |
| 1315 | Zap all SQUIDs. Again the tool in the DCRC Control UI doesn't work, so run the sequence testzap.msl instead. |
| 1330 | Tower = 44.4 mK, settling after the zap. |
| 1345 | Apply +4/-4 bias (to qI&qO on DCRC1/2) |
| 1350 | Start 60 min Bkg data series with S1/S2 = +/-4 V with previous phonon settings, Driver gain = 1, with 1000 initial randoms, trigger on DCRC2pA/B/C/D = 8/8/8/8 ADC using sequence timed_run.msl |
| note: triggering from just one DCRC to avoid multitriggering | |
| DCRC1pC railed a few minutes in. Later DCRC1pD railed as well. Not a very good dataset. | |
| 1440 | End data series a little early |
| 1500 | Adjust the Front-end Gain on DCRCpC and pD down a little, cuz they had some ugly noise. This seems to help. |
| 1505 | Adjust DCRC1pD QET bias from 100.8 to 105, because it looked like it was falling into superconducting. |
| 1510 | Turn charge biases to 0V, then flash detector for 30 seconds |
| 1605 | Tower = 43.4 mK |
| 1605 | Apply +4/-4 bias (to qI&qO on DCRC1/2) |
| 1608 | Start 60 min Bkg data series with S1/S2 = +/-4 V with edited phonon settings, Driver gain = 1, with 1000 initial randoms, trigger on DCRC2pA/B/C/D = 8/8/8/8 ADC using sequence timed_run.msl |
| 1655 | Tower = 43.3 mK. |
| 1655 | Fill LN2 cold trap bath |
| 1710 | Ground and flash detector for 30s. |
| 2320 | Tower = 42.6 mK |
| 2325 | Start Bkg Bias scan at S1/S2 = 0,+/-4,+/-8,+/-12 V, Driver gain = 1, with 1000 initial randoms, 30 min data, 30s flash with 30 min cooldown trigger on DCRC2pA/B/C/D = 8/8/8/8 ADC using sequence qbias_scan_r71_pm_0_4_8_12.msl |