2022/04/11 (Monday)
- Lab in-personnel: Matt
| Status | Run 76 in progress |
|---|---|
| Setup | Cable 2/1/3 → diverter/nothing/nothing → HV CONN1/2/3 → HV 1/2 → DCRC55(1)/DCRC50(3), NaI trigger signal → DCRC52(6) actually discovered later that Cables 1&3 were swapped. |
| 1005 | MC/Coldplate = 27.8/140 mK, Still = 1.11 K / 0.110 mbar / 0 mW, G1/G2= 151/152 mbar, 1K Pot = 18° / 1.61 K / 16±2 mbar, MB = 62.8% |
| 1005 | Goldman = 68.8 mK @ 632 uV excitation |
| 1010 | Fill LN2 cold trap bath |
| 1025 | Plug Kepco 0-1kV power supply into variac, variac plugged into wall with groundless plug. Connect HV to HP voltmeter and to HV box. Doesn't look like any increase in noise. |
| 1025 | Pulses in DCRC3 but none in DCRC1. This is reminiscent of the bad state early in this run. Let's maybe powercycle the DCRCs then zap. |
| 1030 | Stop DAQ programs and disconnect power from DCRCs 1&3. |
| 1050 | Repower DCRCs 1&3, start DAQ programs, zap SQUIDs. |
| 1100 | MC spiked to 65 mK when DCRCs were repowered. Now 30.9 mK and cooling. Seeing pulses in all channels, some rather weak, we'll let it cool further. |
| 1110 | MC = 29.2 mK and cooling DCRC1 channels have no pulses again! What the hell? |
| 1115 | Turn off DAQ programs again and unplug power from DCRC1 only |
| 1120 | Repower DCRC1 and start DAQ programs again. Another MC spike to 65 mK. |
| 1125 | MC = 41 mK and cooling Pulses in all channels, DCRC1 included. OK, let's wait and see if it screws up again. |
| As MC cools below 40 mK see some nasty oscillatory noise in several channels | |
| 1130 | Now no pulses in DCRC1, pulses in DCRC3. Does it have something to do with these nasty oscillations? |
| 1130 | Set DCRC1 QET biases to 0 (previously pA/B/C = 260.8/241.7/258.9). Leave them like that and let tower cool longer. |
| 1145 | MC = 28.4 mK. Restore QET biases to DCRC1 channels. Still no pulses. Dumb. |
| 1150 | Set DCRC1 QET biases to 0 again. Turn off DAQ programs, powercycle DCRC1 again. MC spikes as before. |
| 1230 | dammit - I did NOT have the QET biases at 0. Now it's cooled back to 28.0 mK but no pulses in DCRC1. |
| 1230 | Set DCRC1 QET biases to 0 again. Turn off DAQ programs, powercycle DCRC1 again. MC spikes as before. |
| 1320 | Play with NaI array thresholds. Anthony showed me how to change these. Double the length of DCRC6 traces then count pulses in set number of traces. Results below: |
| Threshold | nominal MeV | N pulses | N traces | Rate [Hz] |
|---|---|---|---|---|
| 4192 | 2.6 | 45 | 100 | 68±10 |
| 4837 | 2.4 | 37 | 100 | 56±10 |
| 3870 | 3.0 | 36 | 100 | 54±10 |
| 2096 | 1.3 | 40 | 12 | 508±80 |
| 1330 | Tower = 27.8 mK. Check pulses on DCRC3 - look good. Set QET biases on DCRC1 channels - no pulses. Bah. |
|---|---|
| 1335 | Turn off DAQ programs, unpower DCRCs. Swap DCRC3 and DCRC1 - now HV 1/2 → DCRC50(3)/DCRC55(1) |
| 1340 | Reset ODB for new setup |
| 1340 | Power DCRC1, then DCRC3. No temperature spike - huh. |
| 1345 | Seeing pulses in most channels but also some nasty oscillations and crazy offsets. Let's zap. |
| 1345 | Zap SQUIDs on DCRCs 1&3 |
| 1350 | Pulses in all channels, though DCRC1pD looks a little weak and weird pulse shapes, and DCRC1pB has pretty strong oscillations. |
| 1355 | Zap SQUIDs on DCRCs 1&3 again. |
| 1605 | Pulses look good in all channels. Had to adjust QET biases - set a few of them higher to avoid strong oscillations. In one case, DCRC1pD, I set the QET bias significantly lower because it was clearly below transition. |
| 1610 | MC = 27.7 mK and flat. |
| 1710 | Do mini-IbIs on DCRC3pA. dP/dI = 0.7/1.0 uV → QET bias = 259.6/274.1 uA. |