| | Current setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55/33/50. |
| | Overnight: Taking background data. Last flash at 7:19 am. Tower temperature stable since then. |
| 0925 | Tower/MC(H35)/MC sensor/Cold Plate = 30.9/25.3/43/145 mK, Still = 1.13 K / 0.11 mbar, G1/G2 = 185/165 mbar, 1K Pot = 1.72 K / 22 mbar, Main bath = 35.4% |
| | Still thermometer lower than usual today. Still pressure unchanged though so unlikely that this is a real temperature change. |
| 0930 | Fill LN cold trap Dewar. |
| 1020 | DIB1 pB is railed. Relocking SQUID shows 50Hz jagged noise that was observed at the end of the day yesterday. Raising the QET bias to 400uA didn't fix it like it did yesterday, but it was only at 400uA briefly. Raise QET bias to 400uA for ~3 minutes. |
| 1035 | Still no change. Changing Signal Source from Feedback to Preamp does nothing. Now the 250Hz sinusoidal noise is also present in all channels. May need a power cycle. Let sit for 5 minutes to see if sinusoid goes away. |
| 1045 | Sinusoidal noise still there. During that break, DIB1 pB QET bias was left at 0uA. Stop and restart the Detector Control VI. Set DIB1 pB QET bias to 128uA (transition QET bias), and the baseline changes appropriately and begins showing pulses. Either restarting the VI or letting the channel sit at 0 QET bias must have helped it. |
| | Sinusoidal noise still there, and now stronger (~30mVpp). Power off boards to allow everything to calm down, then power back on. |
| 1105 | Repower boards and zap SQUIDs. |
| 1115 | After applying settings to DIB1, no sinusoidal noise, and channel pB is working fine with the settings from 2015/09/17. |
| 1150 | After applying all settings to all boards, plug in timing link cables to set up timing link. Sinusoidal noise appears on DIB2 (maybe coincidence). Set up timing link. Only very faint 250Hz sinusoidal noise visible now. Give it a minute. |
| 1200 | Sinusoidal noise is back. Let sit with boards still powered on. |
| 1315 | Commence pumping out LHe transfer tube with scroll pump. |
| 1330 | Commence LHe transfer (27.7%). |
| 1445 | Cease LHe transfer (87.5%). |
| 1450 | Some channels railed, but relock fixes them, and no sign of sinusoidal noise. |
| 1505 | Take 1000 randoms (2min series) at different Frontend Gain values (FG=5/2/5, then 15/5/15, and last 30/10/30). 0V Qbias applied, QETs at transition biases, Output Gain = 3. |
| 1530 | Apparently writing a 0 to the Flash Time field in DAQDAQ still flashes (and doesn't stop flashing), so an accidental mini-bake occurred. Wait for cooldown. |
| 1600 | Start to take data for FG = 15/5/15, but notice some channels are railed. Cannot unrail them even with unlock and modifying Driver Offset. Try lowering FG to normal settings and then ramp up slowly. This causes baseline to shift while increasing FG, and eventually for DIB1 pA, at a FG of 7, the baseline became very noisy and began showing negative “pulses”. |
| | The sinusoidal noise showed up again also. |
| 1630 | Sinusoidal noise still there and cannot rectify strange upside down “pulses” on previously railed channels, so power off DCRCs in preparation for overnight data taking. |
| 1640 | Repower DCRCs and zap SQUIDs. |
| 1705 | Place Cf source under shield for overnight Cf data taking. |
| 1720 | Set phonon thresholds to same values as yesterday. DIB1 pB is again acting like it's normal (i.e. jagged noise and no response to changes in QET bias). Attempt quitting Detector Control VI and restarting it, then changing QET values, but it doesn't help. Set FG=1, OG=0, and QET=0. Set Polarity to Grounded, and Signal Source to Preamp, then set back to Non-Inverting and Feedback, respectively. Change QET bias back to transition bias, but no change on phB. Set QET bias to 420uA and leave for ~5 minutes. |
| 1722 | Fill LN2 cold trap full. |
| 1735 | Cannot fix DIB1 pB. Place source deeper in the shield nearer detector for overnight activation… |