2015/06/24 (Wednesday)
| 0830 | Remove Cf source. |
|---|---|
| 0850 | Tower = 31 mK, Still = 2 mW / 0.11 mbar, G1/G2 = 220/200 mbar, 1K Pot = 1.69 K / 15 mbar, Main bath = 27.0% |
| 0851 | Stop data run, zero Q bias, flash. |
| 0855 | Fill LN cold trap Dewar |
| 0903 | Start data run. |
| 0920 | Stop data run, zero Q bias, flash. |
| 0929 | Start data run. |
| 0945 | Stop data run, zero Q bias, flash. |
| 0954 | Start data run. |
| 1010 | Stop data run, zero Q bias, flash. |
| 1033 | Start data run. |
| 1050 | Stop data run, zero Q bias, flash. |
| 1129 | Start data run. |
| 1145 | Stop data run, zero Q bias, flash. |
| 1205 | Start data run. |
| 1220 | Stop data run, zero Q bias, flash. |
| 1245 | Did some tests of event rate versus Ba source position. Triggering on DIB1pA (only) with a threshold of 200, timed how long it took for 10 triggers: |
| Ba position, down from top of shield | Trigger rate |
|---|---|
| no source | 10/4.0 sec |
| 0 in. | 10/2.4 sec |
| 6 in. | 10/1.9 sec |
| 12 in. | 10/<1 sec |
| 1250 | Estimated the amount of pileup events as a function of source position. Ba at 12 inches : 50% pileup; Ba at 6 inches: 30% pileup |
|---|---|
| 1300 | Estimated minimum phonon thresholds (to nearest 5) to avoid triggering on noise, for each phonon channel. Basic criterion was to have less than 10% noise-like pulses. |
| Minimum thresholds | ||||
|---|---|---|---|---|
| pA | pB | pC | pD | |
| DIB1→DCRC31 | 20 | 20 | 20 | 20 |
| DIB2→DCRC33 | 25 | 15 | 20 | 15 |
| DIB3→DCRC50 | 15 | 15 | 15 | 15 |
| 1316 | Test run to see what event rate the MultiDAQ can handle. Ba at 6 inches: rate 13 Hz, CPU 67%; Ba at 12 inches: 12 Hz, 62%; Ba at 24“ (detector level): 12 Hz, 70%. Strange: unlike previously, we are unable to “choke” the DAQ with data. |
|---|---|
| 1330 | Another rate versus position test, this time with DIB1pA threshold=300: |
| Ba position, down from top of shield | Trigger rate |
|---|---|
| no source | 10/6 sec |
| 0 in. | 10/4 sec |
| 6 in. | 10/3.5 sec |
| 12 in. | 10/3 sec |
| 18 in. | 10/3 sec |
| 24 in. (det. level) | 10/2 sec |
| 1405 | MC/Tower = 25.4/31.2 mK, Cold plate = 146 mK, Still = 2 mW / 1.15 K / 0.11 mbar, G1/G2 = 220/200 mbar, 1K Pot = 1.68 K / 15 mbar, Main bath = 16.5%. Switching the thermometer switch/plug did not cause any phonon channel railing. |
|---|---|
| 1411 | Tried pencil sharpener again. 9/12 phonon channels railed. Could restore them with relocks but 6 of them had shifted baselines requiring new driver offset settings. |
| 1530 | Received DCRC55 (RevC.1) from Bruno. Set IP to 131.225.52.95 |
| 1600 | Remove DCRC31 and connect DCRC55 to DIB1 |
| 1650 | Zap SQUIDs on DCRC55. Find SQUID setpoints: |
| DIB1 DCRC55 SQUID Settings | |||
|---|---|---|---|
| Channel | Bias (mA) | Lockpoint (mV) | Vpp |
| A | -87.05 | -4.86 | 0.384 |
| B | -85.94 | -3.89 | 0.356 |
| C | -83.99 | -4.28 | 0.361 |
| D | -83.98 | -2.82 | 0.357 |
| 1700 | Commence LHe transfer (11.3%). |
|---|---|
| 1735 | Cease LHe transfer (85.6%). |
| 1755 | Producing IbIs curves for DCRC55→DIB1 |
| 1805 | Begin overnight flashing, all 3 DIBs. |
| 1810 | Place Cf source in shield at detector level for overnight activation |