2021/06/18 (Friday)
- Lab in-personnel: Matt
| Status | Run 74 in progress. First cooldown after IVC rebuild. Started circulation last week. |
|---|---|
| Tower thermometer is reading high, probably this is a thermometer problem and the actual temperature is much lower. High noise in some of the charge channels. | |
| Setup: DIB1/2+acc → SL 41/43 → 3.2 MHz filters → cables 2/3 → nothing/Source_mover_board+HV_diverter_board → DCRC50(3)/55(1). Kepco 40V supplye → HV BNC. No lead/poly shield. | |
| 1300 | Tower/MC/Coldplate = 152/32.6/197 mK, Still = 1.44 K / 0.080 mbar / 0 mW, G1/G2= 172/167 mbar, 1K Pot = 1.64 K / 24±2 mbar. MB = 67.1% |
| This is a lower Tower reading than we've seen before. Coldplate and Still are reading high, we've seen this before - both of these thermometers (which share a fridge cable) will show bimodal behavior. | |
| 1305 | Fill LN2 cold trap bath. |
| 1300 | At 10kHz noise in DCRC3qI/qO/DCRC1qI/qO = 33/4.4/3.1/46 e-6. This is q3/q1/q4/q2 At 3kHz (peak) noise in DCRC3qI/qO/DCRC1qI/qO = 1500/170/120/2200 e-6 |
| Higher noise than yesterday. Although q4 is not a lot higher. | |
| 1330 | Look at pulses and try applying negative bias to Side2. Oddly we can set to a much lower trigger threshold today (80) on DCRC1qI without triggering on noise. Observations: start seeing some pulses at -3 V at -15 V temporary disturbance in the trace, then MC temperature starts increasing. Traces look fine after the temporary disturbance, although seems like pulses aren't as big. over a few minutes MC rises from 32→39 mK try -20V, MC temperature starts rising faster, reaches 44 mK before stopping never went into a “breakdown” mode on the traces |
| 1340 | Flash detector |
| Start setting up to test source mover. Refer to March 24 | |
| 1345 | Disconnect source mover from Arduino and plug in the spare motor, to test it. Plug power in from GWiNSTEK supply and set to 7.1 V, light on red board comes on. Plug usb from fridge computer into arduino. Doubleclick Arduino_Create_Bridge_shortcut on desktop and open arduino web editor page. Used “sign in with google”. Select Web Editor from menu. |
| 1355 | Try selecting Monitor - but it is dead, “Serial port unavailable.” Keep trying to restart the Create Bridge, and unplug/replug USB, no dice. |
| 1652 | Start 35min series of 0V/-15V data (bias applied after 1 min), with 1000 beginning randoms, trigger threshold none/none/100/none on DCRC3qI/qO/DCRC1qI/qO, 5Hz in-run randoms, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). Start sequence with Start button. |
| 1700 | DCRC1qI was triggering constantly - had to change threshold to 1000 (!!!) to reduce rate (so weird - the noise is the same as before pretty much). |
| 1700 | Traces look OK, no breakdown noise. MC temperature rising, 32→41 mK |
| 1720 | MC flattens around 45 mK. Tower thermometer = 172 mK. Coldplate = 199 mK |
| 1725 | Dial HV down to 0V. Then short HV leads together, which causes disturbance in trace as usual. Stop run a couple minutes later. |
| 1730 | MC has relaxed to 35.5 mK, still falling. Tower thermometer = 160 mK. Coldplate = 197 mK |