2020/07/25 (Saturday)
- Lab in-person: Matt
- Virtual partner: Nick
| 0740 | Matt Fritts body temperature = 97.4 F |
|---|---|
| Setup | Run 73. DIB 1/3/4 → Stripline 43/48/41 → Cable 3/1/2 → nothing/nothing/accessory_interposer → HV_Conn 1/3/2 → HV 1/2 → DCRCX(4)/DCRC50(3)-master; DCRC33(2) → HV control. DCRCs on overnight. Lead/poly shield erected (4 lead walls, 2 poly walls). |
| 0655 | MB = 30.8% |
| Yesterday the Tower temperature took an upward excursion for a while after the LN2 fill, maximum 57.0 mK, but it has cooled steadily from 3pm till this morning | |
| 0810 | Reset QET biases to higher values to avoid oscillations. All are near the top of their transitions: QET Bias DCRC4/DCRC3 = 0,330,360,0/0,380,400,460 |
| 0810 | Tower = 53.4 mK. (Temperature went down a little after adjusting the biases, maybe the oscillations were heating it slightly) |
| 0812 | Start a 60 min series at HV = 0, CDMS detector: Driver Gains = 1x, DCRC4/3 QET biases = (0,330,360,0)/(0,380,400,460) uA, Front-End Gains = (3/3/3)/(5/5/5) 1000 BOR randoms, trigger on DCRC1pD threshold = 4 Use sequence SimpleDataLoopNoFlash.msl |
| 0830 | Write a sequence Al_flash_DCRC3.msl to do the hot Al flashes like we did in R71 after moving the source |
| 0905 | Matt arrives in lab |
| 0910 | Tower/MC/Coldplate = 53.4/29.5/188 mK, Still = 1.45 K / 0.15 mbar / 5 mW, G1/G2= 276/257 mbar, 1K Pot = 1.66 K / 30±2 mbar. |
| 0915 | Fill LN2 cold trap bath |
| 0927 | Start LHe transfer @ MB = 25.0% |
| 0945 | Tested source mover control. Plugged the extra motor into the control board: plug into red board, wires from one motor into [a], wires from the other in [b]. Turn on GwINSTEK power supply, plug into BNC on control board, turn voltage up to 7.1 V. Light comes on on the red board at above around 3.5 V (Nick says it should work anywhere between 3 and 15 V). |
| 0950 | From the web browser, create.arduino.cc/editor(etc), logged in as Nick, type “help” into Send to see commands. Try mv commands: mv +48 for one rotation forward, mv -96 for two rotations backwards - it works. |
| 0955 | Nick says that the sequence we used to run it for a few steps with a pause and many repetitions is Python code, not clear how to send it from the fridge computer running Windows. We should be able to plug it into jiajin and communicate from there. May not be able to do it remotely. Need to figure out how to communicate to one of the COM ports from a terminal (it's not telnet, it's a serial connection). We were sorta able to connect from the fridge computer using PuTTY, using a serial connection to COM4 - we saw the “hello” greeting but we weren't able to type in commands. |
| 1002 | End LHe transfer @ MB = 92.4% |
| 1045 | Matt leaves lab |
| 1310 | Processed and analyzed this morning's data. After raising the QET biases noise is better by about a factor of 2 (3.7 keVee) but still 1 order of magnitude worse than Run72. Gain is much lower than Run72, like 20% or less. Why? |
| 1310 | Maybe for some reason the QETs have trapped flux. Let's try a hot Al flash, like we do for the source mover. This should also serve as a detector flash/bake. |
| 1315 | Do hot Al flash using DCRC3 LEDs using sequence Al_flash_DCRC3.msl Tower temperature rises to 94 mK then falls. That's not very high. |
| The settings for hot Al flash are LEDPulseWidth/LEDRepRate/LED1,2Current = 400/500/0.8. This is in contrast to standard flash settings, 100/5000/0.6 | |
| 1320 | Turn on LED1 for 2 minutes. Tower rises to 87 mK. Turn off LED for a bit to let it cool |
| 1325 | Try negative LED current, no heating. |
| 1320 | Turn on LED2 for 2 minutes. Tower rises to 88 mK. Turn off LED for a bit to let it cool |
| 1335 | Try the standard flash settings, turn on LEDs. Didn't see any temperature rise. The hot settings still cause heating though. |
| On Feb 25 in Run 72, LEDs heated Tower to 500 mK in 10 seconds. What's wrong this time?? It was a different DCRC but why should that matter?? | |
| 1525 | Tower = 53.6 mK |
| 1530 | Try turning on the LEDs with the standard flash settings. After 3 minutes Tower only warms to 55.1 mK. Turn them off again. |
| 1535 | Try turning on LEDs again with standard width and rate but increase current 0.6→1.0 mA. After 3 minutes Tower warms to 55.8 mK. Turn them off again. |
| 1540 | Try again with 1.0 mA, width 500, rate 100 (this is a mostly-on mode). After 3 minutes reaches 117 mK. Turn them off again. |
| 1545 | Try again in this 500/100 mostly-one mode, but increase current 1.0→1.5 mA. After 3 minutes reaches 128 mK. Turn them off again. |
| 1555 | Try again with current at 3.0 mA. (Not sure how high it goes). After 3 minutes reaches 130 mK. Turn them off again. |
| Took another look at pulses, they still seem really weak. I'd like to try warming the detector above 1.2 K and back down, in case there is trapped flux in the QETs for some reason. We could try suspending circulation and turning on the MC heater. I'll try this, and monitor the fridge pressures - if they get too high I'll release some pressure into the dump. | |
| 1640 | Tower = 54.1 mK |
| 1640 | Close V6 completely. After a few minutes Still pressure starts rising. Tower temperature rising a little. Condenser pressure falls. |
| 1645 | Tower temperature rises above 100 mK |
| 1650 | Tower = 390 mK and rising steadily. Let's give it a boost with the MC heater. |
| 1650 | Turn on MC heater → 1 mW. Doesn't do much. Try 10 mW. Looks like it's warming a bit faster. |
| 1655 | Tower reaches 1.3 K. Turn off MC heater. |
| 1655 | G1/G2 = 144/140 mbar |
| 1655 | Restart circulation: V6→12.8%. Condenser peaks at 180 mbar. Tower → 1.28 K |
| 1705 | V6→13.2%. Condenser peaks at 220 mbar. Tower → 1.23 K. Temperature flattish, maybe because we're working to get the Al into s/c |
| 1715 | V6→13.4%. Condenser peaks at 275 mbar. Tower → 1.19 K. |
| 1730 | V6→13.6%. Condenser → 340 mbar without peaking. Still → 55 mbar. Tower rises → 1.46 K. |
| 1740 | Turn off Still heater, it was still at 5 mW |
| 1745 | Condenser = 360 mbar, Still = 65 mbar, Tower = 1.49 K. Condenser hasn't peaked but let's try opening V6 more anyway |
| 1745 | V6→13.8%. Condenser → 430 mbar without peaking. Still → 60 mbar. Tower dips a little then rises again → 1.46 K. |
| 1750 | V6→14.0%. Trying to power through, although it's having trouble. Maybe should have let Condenser pressure get lower before trying to start circulation. |
| 1755 | OK looking better now, Condenser peaks at 470 mbar and now falling again, Still → 6.5 mbar, Tower finally cooling again → 1.28 K |
| 1800 | V6→14.4%. Condenser → 350 mbar, Still → 2.6 mbar, Tower → 1.07 K |
| 1810 | V6→15.0%. Condenser peaks at 350 mbar, Still → 1.5 mbar, Tower → 0.73 K and dropping quickly |
| 1820 | V6→100%. Condenser peaks at 370 mbar, Still → 0.22 mbar, Tower → 0.48 K and falling |
| 1830 | Tower = 200 mK, Condenser = 330 mbar, Still = 0.17 mbar |
| 1950 | Tower = 58.6 mK, Condenser = 234 mbar, Still = 0.12 mbar |
| 1950 | Switch on Still Heater → 5 mW |
| 1950 | Pulses are back but they don't look any better. What gives??? Why is it so different from Run72? |