2015/06/22 (Monday)
| 0852 | MC/Tower = 25.6/31.2 mK, Cold plate = 159 mK, Still = 2 mW / 1.26 K / 0.120 mbar, G1/G2 = 210/205 mbar, 1K Pot = 1.70 K / 15 mbar, Main bath = 40.5% |
|---|---|
| 0902 | Fill LN cold trap Dewar |
| 0945 | Anthony was demonstrating his stable mode of data taking, but for some reason this morning a railing event occurred and DCRC31 went into a bad state - there was noise in the charge channels indicative of a cold FET… we were able to restore them with FET heating but when trying to restore pA, the pulses looked small and distorted, so we tried modifying the QET bias but it seemed unresponsive, as if DCRC31 was not responding to the command (as it sometimes does). This along with temperature spikes and a raised background temp compelled us to powercycle the DCRCs. |
| We tried to determine what we did differently this morning that caused the bad state, because Anthony had the DAQ running smoothly. One thing were that MCF did a cryo checkout, which involved switching the thermometer switch and plug so that the LakeShore bridge was alternately exciting different thermometers. Could this cause some interference?? We tried to recreate this later but could not cause any railing or shifting by playing with the thermometer plug. | |
| 1130 | Restart DCRCs and set to standard settings. |
| Note: | DIB1 pA threshold was set to 1 during testing, and left at that value - so the next few runs have this very low threshold for DIB1pA. |
| 1200 | Flash and begin taking data in the current mode, using MultiDAQ vi. |
| Current driver offsets | ||||
|---|---|---|---|---|
| DIB | A | B | C | D |
| 1 | 0.032 | 0.032 | 0.026 | 0.038 |
| 2 | 0.032 | 0.032 | 0.026 | 0.038 |
| 3 | -0.086 | -0.102 | -0.108 | -0.110 |
| 1221 | Start another run with updated driver offsets only needed for DIB1: |
|---|
| Updated driver offsets | ||||
|---|---|---|---|---|
| DIB | A | B | C | D |
| 1 | 0.036 | 0.024 | 0.028 | 0.040 |
| 1228 | Sharpening a pencil with the electric sharpener corresponded with a massive railing event - all phonon and charge channels. Temperature increases. FETs seem to be cold on DIB1. DCRC31 appears unresponsive. Disconnecting DCRC31 causes temperature to drop / stop rising. |
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| 1250 | Begin running with updated driver offsets: |
| Updated driver offsets | ||||
|---|---|---|---|---|
| DIB | A | B | C | D |
| 1 | same | same | same | -0.012 |
| 1307 | Try pencil sharpener again: some channels rail but all DIB1 ones OK, no temperature rise. Unplug pencil sharpener. Note: the orange outlets, presumable “clean” power, seem to share a ground with the gray outlets, presumably “dirty” power. |
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| 1408 | Started 15 minute background run, promptly stopped run as disk was full. Deleted some already-copied files on the DAQ computer. (Currently new data is copying to storage automatically every 45 minutes.) |
| 1430 | Started shield construction. |
| 1445 | After clearing up some disk space and flashing, started ~15 minute (not counting randoms) background run. Run may be a bit longer as we changed a couple driver offsets to fix railed phonon channels without restarting and started timer late. Changed driver offsets as follows DIB1 PD = 0.010V, DIB2 PC = -0.062 |
| 1500 | Ended background run. Flashed detector. |
| Note: | after this point, DIB1pA threshold is set to a normal value. |
| 1630 | Reset all phonon thresholds to 25. Note: runs from the previous few days had thresholds set to 50. |
| 1750 | Begin LHe transfer (27.6%). |
| 1830 | Cease LHe transfer (93.5%). |