2022/01/07 (Friday)
- Lab in-personnel: Matt
| Status | Run 75 in progress |
|---|---|
| Setup | Tower Faces 5/3/2 → Cables 2/1/3 → nothing/diverter_board/nothing → DCRC55(1)/DCRC50(3)/DCRCx(4) Lead shield in place. Am Source y = 10.05 mm |
| 1350 | Goldman = 49.4 mK |
| 1350 | Establish communication with Arduino. This causes a temperature spike because I'm working remotely so I didn't turn off the GwINSTEK power supply output. Goldman spikes to 0.48 K then cools. |
| 1355 | Set dwell to 40 ms |
| 1400 | Do mvNwait -4steps×151 times, 40 second wait, with dwell = 40 and power = 6.8 V. (Around 5.93 mm/hour) This sequence will take 1hr40min40sec and will move the source a total distance of 9.96 mm. Should end at 3:40 pm. After about 27 moves temperature is around 0.5 K and for some reason is not in the same high-amplitude square wave pattern as before. Peak-to-peak oscillation is only 0.006 K, and period is 40 seconds, so one oscillation per step. There's a longer-period modulation too, around 0.008 mK peak-to-peak, period around 8min15sec = 12.4 moves = 49.5 steps = 1.03 rotations, so pretty close to a 1-full-rotation period. |
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| The occasional dropouts are somewhat reminiscent of the square-wave pattern seen in earlier moves, but otherwise this is a much more sensible pattern. |
| Note that I'm pretty sure the source is moving toward the far endstop. If it's moving toward the near endstop it should hit it after about 47 steps, at around 2:31 pm. We can look for a change in the temperature pattern at that time. But the evidence is strong that we are moving toward the far endstop. Data makes it pretty clear that we've moved toward pC, away from pD on both sides. And photos of tower assembly show that the far endstop is oriented toward pC. The only way it could still be wrong is if somehow the channel mapping in processing is wrong. (As of 3:05 pm no change in temperature pattern seen.) |
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| 1605 | Goldman/Tower/MC(H35)/Coldplate = 100/388/51.6/217 mK, Still = 1.662±0.002 K / 0.130 mbar / 0 mW, G1/G2= 271/247 mbar, 1K Pot = 1.62 K / 17±1 mbar, MB = 59.4%. |
| Note that fridge is still cooling after the move sequence which ended at 15:41, base temperature and circulation pressure elevated. | |
| Again Still thermometer is reading much more stably than earlier in the run | |
| 1610 | Fill LN2 cold trap bath |
| 1615 | Goldman = 76 mK and cooling |
| 1615 | Turn on DCRC1 LEDs with rep rate reduced from 5000 to 500. Turn off LEDs after 3 minutes. Goldman peaked at 1.29 K. |
| 1635 | Goldman = 103 mK and cooling |
| 1635 | Zap SQUIDS on all three DCRCs. Goldman rises 90→100 mK then cools again |
| 1700 | Goldman = 58.9 mK and cooling |