2018/03/09 (Friday)
| Status: Ending run, letting main bath empty. | |
| Overnight we took bias sweep data at ~4.46 K | |
| 0930 | Tower = 4.5 K, 1K Pot = 6.0 K, Fridge (G1) = 550 mbar. IVC pumping pressure = 5.4 nbar, Main bath = 3.4%. |
| 0945 | Begin pumping mixture out of fridge & Cold Trap 1 to dump. causes a cooling effect on 1KPot/Tower, → 4.9/4.1 K, then start rising again. Dump (G2) = 731.4 mbar when pumpout finished. |
| 1010 | One of the square wave series from yesterday had all noise triggers. Set up square wave injection scheme as yesterday by adding switchboard between DCRC3 and readout cables. |
| 1016 | Start 5 min of square wave calibration data with 10Hz, 5mVpp square wave signal on bias electrode, DIB1/2 = DCRC50/55, triggering on DCRC1QI = 300 ADC bins, DCRC bias = 0V, 1000 BOR randoms. |
| 1126 | Try to change to other calibration setup from yesterday: DIB1/2 = DCRC33/50. Keep getting jagged noise. |
| 1130 | Start up with just DIB1=DCRC33. Noise looks good. |
| 1131 | Take 1000 randoms of DIB1=DCRC33 noise data. |
| 1135 | Power cycle a few times, now the noise looks fine. |
| 1136 | Start 5 min of square wave calibration data with 10Hz, 5mVpp square wave signal on bias electrode, DIB1/2 = DCRC33/50, triggering on DCRC2QI = 120 ADC bins, DCRC bias = 0V, 1000 BOR randoms. |
| 1144 | Stop pumping on IVC. IVC = 54 <m>\mu</m>bar. Watching DCRC3QI noise as things warm up. DCRC3QI=0.013Vpp, tower=4.41 K |
| 1150 | IVC = 74 nbar, DCRC3QI=0.013Vpp, tower=4.39 K |
| 1200 | IVC = 100 nbar, DCRC3QI=0.013Vpp, tower=4.36 K |
| 1235 | IVC = 190 nbar, DCRC3QI=0.026Vpp, tower=4.31 K, 1K Pot = 4.98 K. All four channels are still alive, not railed. |
| 1246 | Power down DCRCs. |
| We'll watch the detector resistance rise during warming. | |
| 1248 | MC (Cernox)=4.23 K, DIB1 qIbias-QET D = 1.22 nS |
| 1300 | IVC = 300 nbar, Tower=4.23 K, 1K Pot = 4.93 K |
| 1300 | Disconnect pump manifold from IVC and connect it instead to the cryostat vacuum jacket. Main bath < 0% |
| 1310 | Pump out line leading to cryostat vacuum jacket down to 40 ubar (not very low for some reason). Open vacuum jacket valve for a minute - pressure goes down to 10 ubar. So we let a little air in - didn't seem to cause a boiloff. |
| 1315 | Let 140 ubar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Looks like this wasn't enough to start a boiloff. |
| 1320 | Let 740 ubar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. This also wasn't enough. |
| 1325 | Actually it looks like maybe this was just enough to cause some warming. Tower temperature is rising slowly. Recovery meter is spinning faster, 1 sqft/24 seconds. Surface of main bath is 21.7 C, about 1 C below room temperature. |
| 1330 | 1K Pot temperature increased from 4.90 to 4.94 K, but then fell a bit. Probably the helium in the vacuum jacket condensed and is not quite making a thermal connection to the room. 1KPot temperature came up again. Recovery meter still going but slower, 1 sqft/40 seconds. |
| 1335 | 1KPot/Tower = 4.99/4.36 K, Main bath outer surface = 21.6 C, recovery = 1 sqft/40 seconds. DIB1 qIbias-QET D = 1.84 nS |
| 1350 | 1KPot/Tower/Cernox = 5.07/4.42/4.45 K, Main bath outer surface = 21.4 C, recovery = 1 sqft/64 seconds. DIB1 qIbias-QET D = 2.33 nS |
| 1400 | 1KPot/Tower/Cernox = 5.13/4.44/4.48 K, Main bath outer surface = 21.4 C, recovery = 1 sqft/72 seconds. DIB1 qIbias-QET D = 2.57 nS |
| 1410 | 1KPot/Tower/Cernox = 5.20/4.46/4.51 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/88 seconds. DIB1 qIbias-QET D = 2.93 nS |
| 1420 | 1KPot/Tower/Cernox = 5.24/4.48/4.53 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/72 seconds. DIB1 qIbias-QET D = 3.12 nS |
| 1440 | 1KPot/Tower/Cernox = 5.36/4.58/4.64 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/120 seconds. DIB1 qIbias-QET D = 4.39 nS |
| 1500 | 1KPot/Tower/Cernox = 5.51/4.66/4.72 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/120 seconds. DIB1 qIbias-QET D = 5.74 nS |
| 1520 | 1KPot/Tower/Cernox = 5.63/4.72/4.80 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/100 seconds. DIB1 qIbias-QET D = 6.88 nS |
| 1540 | 1KPot/Tower/Cernox = 5.83/4.83/4.92 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/104 seconds. DIB1 qIbias-QET D = 8.81 nS |
| 1600 | 1KPot/Tower/Cernox = 6.05/4.96/5.04 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/80 seconds. DIB1 qIbias-QET D = 11.15 nS |
| 1625 | 1KPot/Tower/Cernox = 6.29/5.12/5.19 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/120 seconds. DIB1 qIbias-QET D = 13.90 nS |
| 1700 | 1KPot/Tower/Cernox = 6.63/5.36/5.47 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/132 seconds. DIB1 qIbias-QET D = 18.56 nS |
| 1720 | 1KPot/Tower/Cernox = 6.90/5.64/5.71 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/124 seconds. DIB1 qIbias-QET D = 21.67 nS |
| 1755 | 1KPot/Tower/Cernox = >7/6.18/6.30 K, Main bath outer surface = 21.3 C, recovery = 1 sqft/152 seconds. DIB1 qIbias-QET D = 24.15 nS |
| 1810 | Let 740 ubar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Maybe a small increase in recovery rate, 1 sqft/96 seconds |
| 1812 | Let 2.5 mbar He gas into vacuum manifold. Then open cryostat vacuum jacket valve to let this into the vacuum jacket. Maybe a small increase in recovery rate, 1 sqft/96 seconds |
| 1815 | 1KPot/Tower/Cernox = >7/6.56/6.68 K, Main bath outer surface = 21.1 C, recovery = 1 sqft/32 seconds. DIB1 qIbias-QET D = 24.52 nS |
| 1820 | warmup has accelerated |
| 1825 | Sorb/Tower/Cernox = 12.2/7.40/7.40 K, Main bath outer surface = 20.8 C, recovery = 1 sqft/34 seconds. DIB1 qIbias-QET D = 24.76 nS |
| 1840 | Sorb/Cernox = 15.3/9.03 K, Main bath outer surface = 20.5 C. DIB1 qIbias-QET D = 24.87 nS |