| | Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3), Tower has been cooled below Al transition with mu-metal shield at standard position |
| | DCRCs powered overnight. Pumping on IVC with turbo pump overnight. |
| 0851 | Fill LN2 Cold trap full. |
| | Tower/MC/Coldplate = 38/47/154 mK, Still = 1.30 K / 50 μbar, G1/G2 = 154/140 mbar, 1K Pot = 1.43 K / 1.8 mbar, MB = 68.9%. Tweak 1K Pot.
Boiloff rate: good. Yesterday's pressure releases at 5min and 55min worked OK. |
| 0930 | Disconnect DCRCs to do another electrical check at the breakout box. On DIB1 got “defaults” for qInner and qOuter Bias→Drain (20 nS), Bias→Source (20 nS), Drain→Bias (<1 nS), Source→Bias (<1 nS), Feedback→Bias (<1 nS), Chassis→all(<1 nS). For DIB2, all are ok except qInner Feedback→Chassis is 26 nS. This short is probably what's causing the problem with the qInner channel. |
| 1030 | Repower DCRCs, zap twice, look at phonon channels. DIB3 channels require extreme driver offsets which is strange. DIB1 pA has some scratchy noise and low amplitude pulses. Repower these two DCRCs. |
| 1150 | Still trying to get the channels to look right. Noise on DIB3 pC so tried modifying the SQUID tuning: was SQUID bias[μA]/lockpoint[mV] = -80.3/-2.47, changed to -66.0/-13.9. Then there was squiggly noise in the phonon channels, and on DCRC1 for some reason there were no charge traces (they seemed to be railed). Repower DCRCs again. |
| 1218 | Started programs and zapped squids before setting up timing link |
| 1345 | DIB1 charge both railed at 7V. Realised that we have DCRCs 50 and 55 swapped, this is certainly the source of much of our woe today. Powering them down and connecting properly with DIB1/2/3 → cables → 3.2 MHz filters → DCRC55(1)/33(2)/50(3) |
| | Also corrected a few ODB settings by comparing to previous ODB files. We set: DCRC*/General/ChargePrepulseSamples=500, DCRC*/General/PhononPrepulseSamples=500, Logger/Write as CDMS series=y, Triggerfe2/Common/Period=200 |
| 1355 | Zapping squids |
| 1405 | Reapplied phonon settings that were used on 2016 July 27 12:40. That's the last good data that was taken. |
| 1441 | All channels look good except DIB2 QI, which has a known short (see 0930 above) |
| 1645 | Perform mini-IbIs on all phonon channels to see how close we are to target R_tes_biased of 200 mΩ. Adjusted several QET biases to get closer to target. |