2022/06/30 (Thursday)
- Lab in-personnel: Matt, Giulia, Scott, Zach
| Status | Run 76 in progress |
|---|---|
| Setup | Cables 2/3/1 → diverter/nothing/nothing → Side2-readout HV CONN 1/3/2 → HV 1(L)/2(R) → DCRC50(3)/DCRC55(1), DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) Lead/poly shield fully assembled. Boron-filled socks covering NaI detectors. |
| DCRCs off. | |
| 1115 | MC/Coldplate = 26.7/141 mK, Still = 1.02 K / 0.095 mbar / 0 mW, G1/G2 = 141/141 mbar, 1K Pot = 45° / 1.55 K / 8.0±0.5 mbar, MB = 74.6% |
| 1126 | Filled LN2 cold trap dewar |
| 1430 | Check source mover motor coils again at breakout box. All coils read open with multimeter. Check in nS, all read around 0.1 nS, also check from coil to chassis, all around 0.1 nS. Set up a circuit with the GwINSTEK power supply, apply voltage to coils with 1 kOhm resistor in series, read voltage across resistor to see if there's any current. Ramping voltage as high as 31 V, see no voltage on test resistor, <0.1 mV. That means coil resistances >310 MOhm. Tried this on all four coils. |
| 1510 | Reconnect Cable 2 to diverter board. Plug DCRC1&3 back in. |
| 1540 | Look at HV. With DCRC2qI = 11.66, HV on HP meter was reading around -110 mV. Adjusted qI, found a new minimum at qI = 11.52, this gives around -90 mV |
| 1635 | Power glitch shut off fridge pumps. Didn't notice for 15 minutes. Fridge pressures fell to around 70 mbar, 1K Pot pressure shot up off scale - in fact G3 was reading 115 mbar+1atm (I guess pressure equalized with MB pressure). 1K Pot temperature → 3.37 K. Still pressure rose to 50 mbar then after several minutes started going higher. There was a gap in readout from the MC thermometer but by about 16:50 it was up to 430 mK. |
| 1650 | Restart pumps in the pump alley at the power box - first press “Mains On” then “Reset”. Things start recovering quickly. |
| 1705 | MC = 100 mK and cooling. G1/G2 around 175 mbar, higher than before, but falling. Still = 0.120 mbar, also a little high. 1K Pot pretty much back to normal. |
| 1715 | MC = 45 mK and cooling. Things seem to be settling back to normal. A little concerned with 1K Pot though, 1.53 K / 6.5 mbar and pressure is very flat rather than the normal oscillation. Also 1K Pot temperature much flatter than usual. |
| 1720 | Open 1K Pot needle valve wider, 45° → 60°. 1K Pot → 1.55 K / 7.5 mbar. Still looks pretty flat, we'll see how it goes. |
| 1800 | 1K Pot starts oscillating again, good! |
| 1810 | MC = 29.3 mK, back to base pretty much. |