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2020/08/17 (Monday)

Previous Day

  • Lab in-person: Matt
  • Virtual partner: Pramod
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).
0825 Tower = 50.9 mK
0830 Matt Fritts body temperature = 97.8 °F
Yesterday there was spikey noise in DCRC1pD that we didn't have in the past. In the RQ data it is evident when you compare PFWKmax in randoms. It looks like it's still present. I'll take some 0V data so we can compare with other 0V series.
0835 Check phonon channels, adjust offsets. Seems like maybe DCRC1 offsets had all shifted up somewhat.
0839 Start a 15 min series 0V,
CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420)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
Forgot to enable triggering on this data series
0840 Tower = 50.8 mK
0926 Start a 15 min series 0V,
CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420)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
0926 Tower = 50.5 mK
At 0V there doesn't seem to be so much “spikyness”
1000 Let's try more +75V data. This didn't show spiky noise a couple days ago. Write a new sequence for +75V, 30.1 mV/s, 1min pause after rampup, but only 15 minute duration.
HVdrift_pos75V_1min_30p1mVps_multiloop10_15min.msl
1010 Start a 15 min series at HV = +75V, drifting 0.0301 V/s, 1min pause after rampup,
CDMS detector: Driver Gains = 1x, DCRC4/1 QET biases = (0,320,370,0)/(0,360,420,420)uA, Front-End Gains = (3/3/3)/(5/5/5)
1000 BOR & 5 Hz in-run randoms, trigger on DCRC1pD threshold = 8
Use sequence HVdrift_pos75V_1min_30p1mVps_multiloop10_15min.msl
1008 Tower = 50.3 mK
1012 Vtest = 3.7 mV shortly after drift begins. Drift appears to start at +76.1 V. 1.9% HV loss.
1027 Vtest = 4.1 mV, HV = 103.0 V, drift ends. 1.6% HV loss. Lag ratio = 1.1ish.
1030 Tower = 50.1 mK.
Spiky noise seems to be gone. Either it is only present
at +100V, or it simply disappeared.
1130 Matt enters lab
1130 Tower/MC/Coldplate = 50.5/34.7/188 mK, Still = 1.39 K / 0.12 mbar / 0 mW, G1/G2= 391/353 mbar, 1K Pot = 1.65 K / 28±2 mbar.
Coldplate and Still thermometers are in their “low mode”

Plan for adding more 4He to mixture. Currently the total mixture is around 700 mbar; at the end of Run50 it was 800 mbar. We'll target adding 50 mbar for total 750 mbar.

  1. Stop circulation and pump mixture out of fridge to dump
    1. Close V13B and open V9 (divert mixture to dump instead of LN2 Trap 2)
    2. Open V3 (pump condenser and trap to dump). Wait till G1 is lowish. maybe should instead close V6 then open V5 to do this
    3. Close Condenser Speedivalve and Still Gatevalve (to isolate fridge)
    4. Close V1, V3, V6.
  2. Stop pumping 1K Pot (because we'll want to use the pump)
    1. Close 1K Pot Needle Valve
    2. Close 1K Pot Speedivalve and V4a
  3. Add 4He (either our normal 4He or borrow purer 4He from Goldman lab). Refer to Run 50 method
    1. Purge 4He hose and connect to IGH Vent port
    2. Open V5a, V2a, V7 (to pump out manifold). Wait till P2 is low then close V2a, V5a.
    3. Note G1 pressure (LN2 Trap 2)
    4. Open Vent Speedivalve briefly then close (letting some 4He into manifold). Then Open 11b and close it. Note increase at G1. Repeat to increase G1 by ~300 mbar.
    5. Note G2 pressure (dump)
    6. Open V5 (to pump trap to dump). Note increase in G2.
    7. Repeat last 3 steps until G2 (dump) has increased by about 50 mbar.
  4. Switch to a clean trap
    1. Check contents of warm LN2 Trap 1, then pump it out with 4He pump.
    2. Put LN2 Trap 1 into LN2 Trap Bath
  5. Let mixture from dump into fridge, start 1K Pot, start circulation in standard fashion.
1200 Nicholas Lewellyn from the Goldman lab says they have “enable grade” 99.999% helium, so we'll borrow that. Our industrial grade is 99.995%. Using the purer stuff will introduce less air into our mixture.
1205 Fill LN2 cold trap bath
1215 Hook up 99.999% He cylinder to our gas supply system: 2060 psi.
1220 Close V13b and open V9 to divert mixture to dump. Before opening V3, reduce V6 to 13.5%. Then open V3 to pump condenser to dump.
Tower rises to >300 mbar
maybe should have opened V5 instead. Opening V6 let a lot of gas into the Still.
1230 Looks like V6 wasn't open enough, open it to 50%, then pump out Fridge again. Tower reached 0.56 mK but is now falling.
1235 Stop pumping out fridge, close Condenser Speedivalve, Still Gatevalve, V1. Open V12B to pump LN2 Trap 2 to dump.
1235 Tower = 0.38 K
1245 Close V3 and V6. No longer pumping out Trap 2.
1245 G2(Dump)/G1(Trap2) = 88.2/1.3 mbar. They seem mostly settled.
1245 Close 1K Pot Needle Valve. 1K Pot → 1.40 K / 2.4 mbar. Close 1K Pot Speedivalve and V4a.
1250 Open V5a, V2a, V7 to pump out manifold (Volume “M”). Let P2 fall to 0.018 mbar then close V2a, V5a.
1250 G2(Dump)/G1(Trap2) = 87.0/1.3 mbar. Note dump pressure is falling. Maybe it was hot from the pump, now cooling?
1300 Open Vent Speedivalve for a fraction of a second, then close. Then open V11b till G1 settles, then close. Repeat once. G1(Trap2)→ 90.8 mbar.
1300 G2(Dump) = 84.1 mbar, trending down. Open V5 to pump Trap2 to dump. Let G1(Trap) fall to 4 mbar then close V5. G2(Dump) → 89.7 mbar
Added 5.6 mbar 4He to mixture.
1320 G1(Trap2)=5.5 mbar. Open Vent Speedivalve for a fraction of a second, then close. Then open V11b till G1 settles, then close. Repeat a few times. G1(Trap2)→ 154 mbar.
1320 G2(Dump) = 89.6 mbar, flat. Open V5 to pump Trap2 to dump. Let G1(Trap) fall to 4 mbar then close V5. G2(Dump) → 99.7 mbar
Added 10.1 mbar 4He to mixture.
1325 G1(Trap2)=6.9 mbar. Open Vent Speedivalve for a fraction of a second, then close. Then open V11b till G1 settles, then close. Repeat a few times. G1(Trap2)→ 188 mbar.
1330 G2(Dump) = 99.6 mbar, flat. Open V5 to pump Trap2 to dump. Let G1(Trap) fall to 4 mbar then close V5. G2(Dump) → 111.8 mbar
Added 12.2 mbar 4He to mixture.
1330 Tower/1K Pot = 0.60/3.4 K, both creeping up
1335 G1(Trap2)=5.4 mbar. Open Vent Speedivalve for a fraction of a second, then close. Then open V11b till G1 settles, then close. Repeat a few times. G1(Trap2)→ 188 mbar.
1335 G2(Dump) = 112.1 mbar. Open V5 to pump Trap2 to dump. Let G1(Trap) fall to 2 mbar then close V5. G2(Dump) → 124.4 mbar
Added 12.3 mbar 4He to mixture.
1345 We have added 40.2 mbar 4He total to mixture today. We'll stop there.
1345 Pump Trap 2 more thoroughly to Dump for a few more minutes.
1350 Close V12b+Speedivalve to isolate Trap2. Close V5.
1350 Check contents of warm LN2 Trap 1: 8.0. Pump out with 4He pump.
1355 Tower/1K Pot = 0.73/4.1 K, both creeping up
1405 Remove LN2 Trap 2 from LN2 Bath Dewar. Put Trap 1 into Bath.
1405 Open V13a, letting new mixture in Dump cool off in cold LN2 Trap 1.
1410 Open V12a+speedivalve and V1, letting new mixture cool in the 4He Trap before letting it into the Condenser.
1415 Tower/1K Pot = 0.83/4.3 K. Pot flat, Tower rising.
1415 Open Condenser Speedivalve and Still Gatevalve, letting mix into Condenser side of fridge. G1/G2 = 126/116 mbar, don't change much. P1(Still) jumps offscale to 1000mbar, suggesting that there is throughput.
Now to restart 1K Pot and circulation.
1425 Check pressure in 1K Pot: G3 → 75 mbar+1atm. Yikes that's high. It will take a while to pump out with 4He pump… may want to use the scroll pump instead…
1430 Pump out 1K Pot in steps, alternating between V4a and the 1K Pot speedivalve, opening V4a for short bursts only when the mechanical gauge read above a few inches. After several iterations leave V4a and 1K Pot speedivalve open. 1K Pot → 1.5 K / 4.0 mbar.
1435 Tower = 1.04 K, cooling at the moment. G1(fridge) = 118 mbar and falling.
1435 Open 1K Pot needle valve → 10°. 1K Pot → 1.45 K / 4.0 mbar.
1440 Open 1K Pot needle valve → 30°. 1K Pot → 1.51 K / 5.5 mbar. Tower = 1.02 K, G1(Fridge) = 116 mbar.
Open 1K Pot needle valve → 45°. 1K Pot → 1.53 K / 6.5 mbar.
1445 Open 1K Pot needle valve → 60°. 1K Pot → 1.56 K / 8.5 mbar. Tower = 1.03 K, G1(Fridge) = 114 mbar.
1450 1K Pot pressure jumps to 30 mbar and starts oscillating. That's probably a good sign.
1505 Tower = 1.09 K, G1(Fridge) = 96 mbar.
1505 Close V9, leaving 96 mbar in dump.
1505 Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 213 mbar. Tower falls to 0.96 K. P1 (Still) falls to 45 mbar.
1515 V6 → 13.2%. Condenser peaks at 239 mbar. Tower → 0.88 K. P1(Still) → 7.0 mbar.
1525 V6 → 13.4%. Condenser peaks at 248 mbar. Tower → 0.80 K. P1(Still) → 4.5 mbar.
1525 Matt leaves lab
1600 Matt Fritts body temperature 97.9 °F
1605 After returning home, Tower has risen to 1.35 K, Condenser = 253 K
1605 V6 → 13.7%. Condenser rises to 320 mbar. Tower → 1.32 K then edges back to 1.34 K. P1(Still) → 4.0 mbar.
Condenser hasn't peaked but I'm going to push forward anyway
1620 V6 → 14.1%. Condenser peaks at 360 mbar. Tower → 1.30 K then bounces back to 1.36 K. P1(Still) → 1.4 mbar
1630 V6 → 14.5%. Condenser peaks at 390 mbar. Tower zigzagging, as high as 1.42 K and as low as 1.29 K. P1(Still) → 0.8 mbar
looks like we are working to get the electrode into s/c.
1640 V6 → 15.0% Condenser peaks/plateaus at 405 mbar. Tower = 1.36 K, zigzagging. P1(Still) → 0.55 mbar.
1700 V6 → 100%. Condenser → 430 mbar. Tower falls → 1.12 K. P1(Still) → 0.12 mbar.
1715 Tower falls below 1K. Good good.
1800 Tower = 0.81 K. Condenser = 438 K. Still = 0.12 mbar.
1800 Open V14 to let the remaining mix out of the dump and into circulation. P1(Still) goes off scale then falls again. Condenser peaks at 750 mbar then starts falling steadily. Tower rises to 0.9 K then starts falling again
1815 Still = 5 mbar and falling
1845 Tower = 0.74 K, G1/G2 = 608/554 mbar, Still = 0.55 mbar
1845 Close V14
1925 Tower = 0.65 K, G1/G2 = 595/544 mbar, Still = 0.18 mbar
2025 Tower = 0.58 K, G1/G2 = 593/542 mbar, Still = 0.18 mbar
2125 Tower = 0.55 K. Turn on Still Heater to 5 mW. Tower starts cooling quickly. G1/G2 rise a little, → 625/571 mbar. Still → 0.22 mbar.
2130 Tower bottoms out at 0.526 K, G1/G2 = 663/606 mbar and rising. Still = 0.24 mbar.
2210 Tower = 0.49 K, cooling. G1/G2 = 689/629 mbar, flat. Still = 0.22 mbar.

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