| Setup | Run 72. DIB 1/3/4 → Stripline 43/41/48 → Cable 3/2/1 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1). DCRCs on overnight. No shield. |
| | overnight: tower temperature falling at constant rate, 0.16 mK/hour, 3.7 mK/day |
| 0855 | Tower/MC/Coldplate = 64.4/31.9/192 mK, Still = 1.57 K/ 0.200 mbar / 0 mW, G1/G2= 133/127 mbar, 1K Pot = 2.11 K / 26 mbar. MB= 65.2% |
| 0900 | Fill LN2 cold trap bath from 25L bomb Dewar |
| 0935 | There are good pulses in all channels except HV1pA (DCRC4pA). That channel has OK SQUID performance but the baseline seems unresponsive to changes in QET bias. Let's try a different DCRC. |
| 0945 | Swap out DCRCX(4) for DCRC50(3) on HV1. |
| 0955 | Zap SQUIDs on DCRC3 |
| 1010 | DCRC3 phonon channels are railed. Try SQUID tuning on a couple channels - behavior doesn't make sense. With SQUID Bias at zero I see a trace (polarity open, source pre-amp) but when you change the SQUID bias the baseline moves a lot - just -1.1 uA and the baseline rails, should be able to set it to -70 or something. |
| 1045 | Try power-cycling DCRC3 |
| 1105 | Zap SQUIDs on DCRC3. But there doesn't seem to be any response to temperature or Still pressure. So maybe it's not working. |
| 1110 | Same problem with SQUID tuning with DCRC3. No idea what's wrong. |
| | Crap! just realized I did not have the DIB1 cable plugged into the HV box, it was plugged into the breakout box to check interchannel connections (which seem OK). So let's try this again. |
| 1115 | Power up DCRC3 again on HV1 and zap SQUIDs. This time I see fridge response. |
| 1120 | OK, now look at DCRC3 pA, pB, pC. pB and pC show pulses as before. pA is unresponsive to changes in QET bias. The simplest conclusion is that DIB1pA QET is open. Possibly one wirebond broke at the detector some time after the tower electrical checkout - during installation or during cooldown. (This TES has the most complicated wirebonding at the detector, involving a hopscotch arrangement.) |
| | So: Side1pE is not working. That's HV1 pA. |
| 1125 | For no particular reason, switch back to DCRCX(4) on HV1. Zap DCRC4 SQUIDs. |
| 1720 | Fill LN2 cold trap bath from 25L bomb Dewar |
| 1720 | Tower = 63.5 mK |
| 1725 | Main bath = 52.7% |