2015/08/27 (Thursday)
| 0840 | Tower/MC/Cold Plate = 31.5/24.6/159 mK, Still = 1.36 K / 0.085 mbar, G1/G2 = 150 mbar, 1K Pot = 1.74 K / 24 mbar, Main bath = 67.3%. |
|---|---|
| note | Thermometers on Fridge Out 1 cable (Still and Cold Plate) are anomalously high. Variac is off, unplugging it didn't help, perhaps interference from something else nearby… |
| 0850 | Fill LN2 cold trap Dewar |
| IbIs results | ||
|---|---|---|
| QET biases chosen for R_bias of 200 mΩ | ||
| DIB1 → cable → 3.2 MHz → DCRC55 | ||
| Channel | QET bias (μA) | R_normal (Ω) |
| pA | 114.0 | 0.57 |
| pB | 127.1 | 0.632 |
| pC | 117.8 | 0.723 |
| pD | 100.8 | 0.701 |
| DIB2 → cable → 3.2 MHz → DCRC33 | ||
| Channel | QET bias (μA) | R_normal (Ω) |
| pA | -112.6 | 0.680 |
| pB | -108.0 | 0.824 |
| pC | -138.9* | 0.997 |
| pD | -97.7 | 0.790 |
| *: this channel had at be set to R_bias of 300 mΩ | ||
| DIB3 → cable → 3.2 MHz → DCRC50 | ||
| Channel | QET bias (μA) | R_normal (Ω) |
| pA | 100.5 | 0.813 |
| pB | 100.7 | 0.739 |
| pC | 92.5 | 0.720 |
| pD | 119.1 | 0.686 |
| 1115 | Set QET biases to above values. Set all Frontend Gains to 1, Output Gains to setting = 1 |
|---|---|
| 1135 | Pulses in DIB2pB showing up negative. Relock gets them back to positive, but they revert to negative after a minute or so. Re-zapping does not help. |
| 1235 | Checking the SQUID modulation on DIB2pB. Some indication of resonances. Redo the SQUID settings: |
| New SQUID setting - output gain setting = 1 | |||
|---|---|---|---|
| SQUID bias (uA) | Lockpoint (mV) | Mod depth (mVpp) | |
| DIB2 pB (DCRC33) | 50.78 | 2.14 | 219 |
| 1245 | DCRC33/DIB2 stopped responding to changes in trigger setting, had to power cycle DCRC. |
|---|---|
| 1320 | DIB2pB pulses remain upright now. (maybe this was just the DCRC reset - note later today we reset to the old SQUID settings and it seemed well-behaved) |
| Take snapshots of noise and pulses, see below. Both look much improved with filters (and cables) present! |
| Noise traces | |
|---|---|
| DIB1 → cable → 3.2 MHz filter → DCRC55 | |
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| DIB2 → cable → 3.2 MHz filter → DCRC33 | |
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| DIB3 → cable → 3.2 MHz filter → DCRC50 | |
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| Sample pulses | ||||
|---|---|---|---|---|
| DIB1 → cable → 3.2 MHz filter → DCRC55 | ||||
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| DIB2 → cable → 3.2 MHz filter → DCRC33 | ||||
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| DIB2 → cable → 3.2 MHz filter → DCRC33 with altered SQUID settings | ||||
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| DIB3 → cable → 3.2 MHz filter → DCRC50 | ||||
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| 1555 | Try resetting DIB2pB SQUID to original settings: SQUID bias 66 uA, lockpoint 3.02 mV. Looks ok now, pulses remain upright. |
|---|---|
| 1510 | Tower = 31.2 mK |
| 1510 | Set MultiDAQ vi for 2000 events/file. Charge biases all 0 V. No flashing. |
| 1512 | Take data, standard QET biases. 1000 randoms plus 5 min triggered, all phonon trigger thresholds at 20 ADCs |
| 1520 | Take data, QET biases = 0 (superconducting), 1000 randoms |
| 1526 | Take data, QET biases = 400/-400/400 uA on DIB1/2/3 (normal resistance), 1000 randoms |
| 1529 | Stop data |
| 1720 | Commence processing 07150827_1512 and 07150827_1523. |
| 1731 | Fill LN2 cold trap full. |
| 1735 | Commence processing 07150827_1527. |
| 1745 | Data finished processing. |