2020/09/11 (Friday)
- Lab in-person: Zach
- Virtual partner: Matt, Derek
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → pi-filters 1/2/3 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC55(1)-master; DCRC33(2) → HV control. DCRCs on overnight. Lead/poly shield erected (4 lead walls, 2 poly walls). |
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| 0625 | Most channels are railed. Zap SQUIDs. |
| 0701 | MB = 27.8% |
| 0820 | Adjust phonon channel offsets. Channels look OK. |
| 0835 | Start a 60 min series at HV = 0V, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,410)uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8 Use sequence SimpleDataLoopNoFlash.msl |
| 0835 | Tower = 50.9 mK |
| 0935 | Tower = 50.6 mK |
| This morning's series had a lot of noise triggers - there seems to be more spiky noise. Messing with the trigger it looks like increasing the threshold from 8 to 12 avoids them. Let's try another zap, see if it goes away. | |
| 1045 | Zap SQUIDs, DCRC1&4 huh - strangely the temperature dropped when the Zap sequence began, from 50.4 to 48.2 mK. A DCRC must have been in a bad state. After the Zap began the temperature rose as usual. |
| 1050 | Zach body temp = 97.0 |
| 1101 | MB = 20.0% |
| 1110 | Zach arrives at lab. |
| 1115 | Tower/MC/Coldplate = 47.2/31.1/187 mK, Still = 1.37 K / 0.095 mbar / 0 mW, G1/G2= 256/287 mbar, 1K Pot = 1.69 K / 50±5 mbar. |
| 1115 | Swapped leads to HV for + bias. |
| 1145 | Begin LHe transfer @ MB = 20.0% |
| 1219 | Ended LHe transfer @ MB = 90.7% |
| 1244 | MB = 90.7% |
| 1245 | Zach leaves lab. |
| 1320 | Tower rose above 110 mK during transfer and now seems kinda stuck above 56 mK. All DCRC1 channels are railed. |
| 1320 | Zap SQUIDs, DCRC1&4 |
| 1340 | Unrail and adjust phonon channels. We're back to the spiky triggers - raising threshold to 12 only partially helps. And Tower still stuck around 55.7 mK - well cooling slowly I guess. |
| 1350 | A couple of sudden temperature drops, in steps, for some reason. Still warm though, now 54.5 mK |
| 1350 | Zap SQUIDs yet again |
| 1410 | Tower 53.5 mK and cooling. Still see spikiness in DCRC1pD |
| 1600 | Tower = 52.5 mK and flat, annoying. Lots of spike triggers at threshold=8, but not many at threshold=10. I'll zap one more time I guess. |
| 1605 | Zap SQUIDs yet again |
| 1850 | Tower = 51.1 mK. Channels look better. DCRCpD triggers OK at usual threshold=8. |
| 1854 | Start a 60 min series at HV = 0V, CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,410)uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8 Use sequence SimpleDataLoopNoFlash.msl |
| 1954 | Tower = 51.0 mK |
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| 2115 | Arduino Editor is still connected to the Arduino. Do rd dwell, verify that it's still 40 ms |
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| 2117 | Move source -4×62 steps with 4 minute pause after each move, mvNwait -4 240 62 |
| This should move the source to y = -9.988 mm (not corrected for thermal contraction). That's about half the radius of pF. Total sequence should take 4hr 8min, ending at 01:25. | |
| first move spikes temperature to about 0.93 K. Later peaks at 1.1 K, minima at 0.8 K. | |
| 2120 | Just noticed that the 1K Pot temperature and pressure have dropped dramatically. It started falling from around 50mbar/1.67K at 15:00, to 8mbar/1.52K by 17:00. This could be a problem - 1K Pot may be about to fail. But so far it doesn't seem to be hurting fridge performance; circulation pressures are down and base temp seems OK. |
| 2125 | Still = 0.065 mbar / 0 mW, G1/G2= 220/200 mbar, 1K Pot = 1.41 K / 2±1 mbar. All of these values are lower than normal. |