2022/01/03 (Monday)
- 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 = |
| 1040 | Goldman/Tower/MC(H35)/Coldplate = 47.7/84.2/37.9/211 mK, Still = 1.68±0.05 K / 0.130 mbar / 0 mW, G1/G2= 246/225 mbar, 1K Pot = 1.61 K / 18±1 mbar, MB = 67.9%. |
| After plugging Goldman thermometer back in, it was reading wrong - I squeezed the connection a little then it read really wrong, and so did other thermometers… temporarily upping the excitation to 200 uV fixed it. But Goldman is reading a bit higher now, 48.2 mK instead of 47.7, at 63 uV. The standard setting this run has been 20 uV. Switching to 20 uV now doesn't change the mean reading but the higher excitation improves the stability - let's switch to 63 uV for the time being. | |
| 1220 | Fill LN2 cold trap bath |
| Couple days ago I moved the source 2.07 mm in what I thought was the +y direction, but the data suggests it went in the -y direction. So let's try moving it the other way. | |
| 1220 | Establish connection with Arduino: (1) turn off GwINSTEK output (2) double-click Arduino Create Bridge on fridge computer desktop (3) go to Arduino webpage/Web Editor/Monitor. |
| 1225 | Set Dwell=40 ms. Turn GwINSTEK output on, 6.8 V |
| 1232 | Do mvNwait -4steps×61 times, 40 second wait, with dwell = 40 and power = 6.8 V. (Around 5.93 mm/hour) This sequence will take 40min40sec and will move the source a total distance of 4.02 mm. Should end at 1:12 pm. After 7 moves Goldman thermometer is in square-wave pattern, 0.3-0.5 K |
Here's that interesting temperature pattern again.
- Square wave period is 82 seconds, that's two moves. As if one move pushes it to a high temperature, the next drops it to a lower temperature - strange.
- Amplitude of square wave modulates, switching from positive to negative between two “beats”
- Full modulation period seems to be about 18.5 minutes = 28 moves = 112 steps = 2.3 full turns. Doesn't make any particular sense…
| 1510 | Goldman = 51.0 mK and cooling |
|---|---|
| 1540 | Goldman = 50.1 mK and cooling |
| 1540 | Zap SQUIDs on all 3 DCRCs. |
| 1630 | Goldman = 49.3 mK and falling. Adjust QET biases based on mini-IbIs trends versus temperature (using 49.2 mK) to target dP/dI = 1.0 uV on all channels. QET biases = 245.5/319.1/279.9/184.3/164.3/165.2/218.3/0/209.2/150.6/259.7/193.5 Adjust driver offsets so all baselines are around -0.9 V |
| 1636 | Start 0V data series, 36 min long, with 1000 initial randoms, no in-run randoms, trigger on DCRC3pB threshold 5. Start series with the Start Button. |
| Goldman = 49.2 mK | |
| 1649 | Goldman = 49.1 mK. Do an in-run QET bias adjustment. QET biases = 245.8/319.3/280.3/184.6/164.6/165.5/218.4/0/209.5/150.8/260/193.8 |
| 1655 | Goldman = 49.0 mK. Do an in-run QET bias adjustment. QET biases = 246/319.6/280.6/185/164.9/165.8/218.6/0/209.7/151/260.2/194.1 |
| 1702 | Goldman = 48.9 mK. Do an in-run QET bias adjustment. QET biases = 246.3/319.9/281/185.4/165.2/166/218.7/0/209.9/151.1/260.4/194.4 |