2015/07/09 (Thursday)
| overnight status: baking detector, no Cf source on fridge (skip a day of activation), DIB1/2/3 → 3.2 MHz pi filter/100 MHz C filter/no filter → DCRC55/33/50 | |
| 0835 | Lab door propped open and light on for some reason |
| 0836 | Tower was at 317 mK during bake but some excursions occurred starting around 7:30 am: Tower up to 360 mK, G1/G2 rose 6 mbar then fell again, Still pressure decreased slightly, 1K Pot pressure and temperature decreased slightly. |
| 0838 | 1K Pot = 1.66 K / 0.10 mbar. Open needle valve 5-10 degrees |
| 0840 | Stop flashing detector |
| 0850 | Fill LN2 cold trap Dewar |
| 0859 | Transfer tube vacuum jacket has not been pumped out for last 6 transfers. During the last transfer it felt a bit cold. Checked vacuum today: only 7.4e-2 mbar (including volumes of three bellows). |
| 0903 | Tower temperature has some variations as it cools, increases as high as 44 mK from 32 mK minimum. |
| 0932 | Pumped transfer tube jacket down to 2e-5 mbar |
| 0941 | Commence LHe transfer (8.3%). |
| 0942 | Temperature variations cease, cooling normally |
| 0943 | Tower = 31 mK, Still = 0 mW / 0.10 mbar, G1/G2 = 200/185 mbar, 1K Pot = 1.67 K / 12 mbar, Main bath = 8.3 % |
*note*: The pulse quality assessments here and in later days are based on looking for “shelving” features or other ugliness like square-ish pulses (sharp dropoffs). As a general rule I choose pulses with around 40 mV amplitudes. |
| Visual Pulse Assessment (no bias) (P: poor; M: mediocre; D: decent; G: good) | ||||
|---|---|---|---|---|
| a | b | c | d | |
| 1 | P | M | M | P |
| 2 | P | M | M | G |
| 3 | P/M | M | P | P |
| 1001 | Tower = 30.3 +/- 0.2 mK (pretty cold) |
|---|---|
| 1030 | End LHe transfer(92.1%). |
| 1043 | Remove filter from DIB1, replace/repower DCRC55. |
| 1053 | Zapped DIB1 SQUIDs twice. |
| 1112 | Set up timing link. |
| 1115 | Set DIB1 phonon settings. Driver offsets: -0.012/ -0.094/ -0.114/ -0.024. |
| Visual Pulse Assessment (P: poor; M: mediocre; D: decent; G: good) | ||||
|---|---|---|---|---|
| a | b | c | d | |
| 1 | P | M | P | M |
| 2 | P | M | P | D |
| 3 | P | M | P | P |
| 1124 | Noise in DIB2 charge 5.5 kHz 6/1 mVpp. All phonons railed. Charge noise disappears after relocking phonons. |
|---|---|
| 1141 | Set DIB3 pC and pD output gain settings to 1, prev. 0, and new driver offsets: -0.176/ -0.044/ -0.092. |
| 1145 | Set phonon thresholds as shown below: |
| Phonon Thresholds | ||||
|---|---|---|---|---|
| A | B | C | D | |
| DIB1 | 20 | 25 | 25 | 20 |
| DIB2 | 30 | 20 | 20 | 20 |
| DIB3 | 20 | 20 | 30 | 20 |
| 1150 | A on DIB2 was at ~0.8 V for baseline. Relocking made it rail. Change driver offset from 0.082 V to 0.034 V. |
|---|---|
| 1152 | Flash 30s. |
| 1213 | Apply -/+4 V, start data run. |
| 1230 | Lots of channels railed. Stop run, zero Q. Railed channels: DIB1 (ABCD), DIB2 (ABCD), DIB3 (BCD). Unlock/relock brought back all except C1. Change driver offsets: C1(-0.114 → -0.030). |
| 1237 | Flash 30s. |
| 1610 | Try powering down DCRCs on DIB1 and DIB3, read only DIB2 phonon. Pulse shapes look much better, no ugly shapes. |
| 1627 | Plug in DIB1 and set up timing link. Introduces some low frequency noise. Pulses starting to look worse. |
| 1633 | Disconnect DCRC55 again. Pulses pretty again. |
| 1700 | Tried DIB1→DCRC55 by itself, other DCRCs off. Ugly pulses (see below). |
| 1737 | Fill LN2 cold traps full. |
here are some of the pulses taken with
| Figure 1: DIB1 DCRC 55 pulses (no other DCRC connected) |
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| Figure 2: DIB2 DCRC 33 pulses (no other DCRC connected) |
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| Figure 3: DIB2 DCRC 33 pulses (no other DCRC connected) |
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| Figure 4: DIB3 DCRC 50 pulses (no other DCRC connected) |
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