2018/03/21 (Wednesday)
| Status: Initial LHe transfer yesterday. Mixture open from dump to fridge through (cold) Trap 1. | |
| 0910 | Tower/Sorb/1K Pot = 5.28/8.3/6.43 K, G1(fridge) = 550 mbar, Main bath = 62.4%. DIB1 qIbias-QET D = 17.01 nS |
| 0910 | Turbo on IVC = 2.2 nbar. IVC = 16 nbar with turbo valved out. |
| 0915 | Fill LN2 cold trap bath |
| 0920 | Pump out line to 1K Pot with scroll pump. Valve out pump and open 1K Pot speedivalve to check pot pressure: 7/30 bar (on mechanical gauge), pretty high. Pot temperature drops when valve opened, to 4.6 K then back up. |
| 0925 | Pump out 1K Pot with scroll pump. Dips to 4.6 K then rises again. |
| 0930 | Switch to pumping 1K Pot with 4He pump. Open valve on pump exhaust line and valve on recovery line to connect pump exhaust to recovery. |
| 0930 | 1K Pot = 6.47 K / 0.50 mbar Open 1K Pot Needle Valve to ~10 degrees. 1K Pot → 3.2 K / 1/30 bar (mechanical gauge; off-scale on P2) |
| 0940 | 1K Pot pressure oscillating strongly, falling overall, minimum around 4 mbar. Tower temperature falling. |
| 0945 | Tower/Sorb/1K Pot = 4.85/4.0/2.80 K, G1(fridge) = 473 mbar. DIB1 qIbias-QET D = 14.70 nS. Tower temperature falling rapidly. Tower = 4.00 K, DIB1 qIbias-QET D = 11.5 nS. |
| 0950 | Tower = 3.37 K, DIB1 qIbias-QET D = 0.50 nS. Tower = 3.35 K, DIB1 qIbias-QET D = 0.15 nS. |
| 0950 | 1K Pot = 2.85 K / 4.0 mbar, flat Open Needle Valve a few more degrees. 1K Pot → 2.77 K / 4.5 mbar |
| 0955 | Open Needle Valve a few more degrees. 1K Pot → 2.72 K / 5.0 mbar |
| 0955 | Tower = 3.27 K, DIB1 qIbias-QET D = 0.07 nS. |
| 0958 | Open Needle Valve a few more degrees. 1K Pot → 2.70 K / 6.0 mbar |
| 1003 | Open Needle Valve a few more degrees. 1K Pot → 2.40 K / 10.0 mbar |
| 1004 | Tower = 3.08 K, DIB1 qIbias-QET D = 0.07 nS. |
| 1016 | Open Needle Valve a few more degrees. 1K Pot → 1.84 K / 13.0 mbar |
| 1018 | Tower = 2.65 K, DIB1 qIbias-QET D = 0.07 nS. |
| 1032 | Open Needle Valve a few more degrees. 1K Pot → 1.56 K / 11.0 mbar, pressure starting to fall. |
| 1033 | Tower = 2.17 K, DIB1 qIbias-QET D = 0.06 nS. |
| 1042 | 1K Pot → 1.51 K / 6.5 mbar, flattening out. |
| 1044 | Open Needle Valve a few more degrees, no change. 1K Pot → 1.51 K / 6.5 mbar |
| 1045 | Open Needle Valve a few more degrees, still no change. 1K Pot → 1.52 K / 6.5 mbar |
| 1048 | Tower = 2.00 K, levelling off DIB1 qIbias-QET D = 0.07 nS. |
| 1050 | Open Needle Valve a few more degrees. Got a response this time. 1K Pot → 1.68 K / 50 mbar and oscillating |
| 1110 | Tower = 1.90 K (flat), Fridge(G1) = 53.1 mbar (falling slowly), 1K Pot = 1.68 K / 50±5 mbar |
| 1155 | Tower = 1.84 K (flattish), Fridge(G1) = 47.9 mbar (falling slowly), 1K Pot = 1.68 K / 50±5 mbar |
| 1235 | Tower = 1.825 K (flattish), Fridge(G1) = 45.7 mbar (flattish), 1K Pot = 1.67 K / 40±5 mbar |
| 1235 | Close V9 leaving 35.3 mbar in dump. Close V3. Turn on 3He pump, which will push a little more mix into condenser. Fridge pressures rise a little then fall again. |
| 1250 | Tower = 1.83 K (flattish), Fridge(G1) = 46.0 mbar (flattish), 1K Pot = 1.67 K / 45±2 mbar |
| 1255 | Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 115 mbar. 1K Pot pressure spikes to 110 mbar then returns. Tower falls to 1.65 K. |
| 1300 | V6 → 13.2%. Condenser peaks at 115 mbar. Tower → 1.57 K. |
| 1310 | V6 → 13.5%. Condenser peaks at 125 mbar. Tower → 1.46 K. |
| 1315 | Still pressure falling, Still = 20 mbar |
| 1315 | V6 → 13.8%. Condenser peaks at 130 mbar. Tower → 1.15 K. Still → 7.0 mbar |
| 1320 | V6 → 14.2%. Condenser peaks at 125 mbar. Tower → 1.06 K. Still → 3.6 mbar |
| 1325 | MC(H35)/Coldplate/Still = 1.02/0.97/1.40 K |
| 1330 | Tower = 0.80 K |
| 1330 | V6 → 15.0%. Condenser peaks at 130 mbar. Tower → 560 mK. Still → 1.7 mbar |
| 1340 | Condenser/Still = 114/1.2 mbar |
| 1340 | V6 → 100%. Condenser peaks at 120 mbar. Tower → 200 mK. Still → 0.22 mbar |
| 1350 | Tower/MC(H35)/Coldplate/Still = 0.097/0.058/0.187/1.38 K |
| 1415 | Tower/MC/Coldplate = 90.7/41.7/168 mK, Still = 1.27 K / 0.130 mbar, G1/G2 = 76/76 mbar, 1K Pot = 1.67 K / 45 mbar. |
| 1415 | Open V14 to let the rest of the mixture from the trap into circulation. Condenser peaks at 105 mbar, Still peaks at 50 mbar, MC rises to 111 mK and plateaus, starts falling again after a couple of minutes. |
| 1430 | Tower = 90.5 mK, Still = 2.0 mbar, G1/G2 = 69/70 mbar, 1K Pot = 1.67 K / 45 mbar. |
| 1500 | Tower = 82.5 mK, Still = 0.4 mbar, G1/G2 = 75/74 mbar, 1K Pot = 1.67 K / 40 mbar. |
| 1500 | Close V14 |
| 1525 | Tower/MC/Coldplate = 78.9/36.4/174 mK, Still = 1.42 K / 0.130 mbar, G1/G2 = 75/74 mbar, 1K Pot = 1.67 K / 45 mbar. |
| 1535 | Plug cables into DCRCs |
| Setup: DIB1/2 → SL 43/41 → 3.2 MHz filters → cables 3/1 → DCRC50(3)/55(1). | |
| 1540 | Power up DCRCs and start MIDAS programs Tower temperature rises 76→78 mK, then falls back to 76 mK. |
| 1545 | Set all four charge biases to +12 V. Seeing some pulses in all four channels. Setting the bias seemed to cause another short temperature spike, maybe this just happened when the first channels were biased and the others were still at ground. |
| 1555 | Adjust thresholds on individual channels |
| 1555 | Start 60min series of 12V data (DCRC bias), with 1000 beginning randoms, and a 80/80/100/80 bin threshold trigger on DCRC1qI/qO/DCRC3qI/qO, with 1.6384 ms pulses (8192 length) and 400 us prepulse (500 length). |
| 1640 | Tower = 67.8 mK, falling steadily |
| 1655 | Set bias on all four channels back to 0 V. Again this causes a temperature spike on the Tower thermometer, 64.3→67.2 mK and back. |
| 1700 | Fill LN2 cold trap bath |
| 1705 | Tower = 63.4 mK, falling steadily |
| 1705 | Turn on DCRC1 LED 1. Tower → 0.25 K. Turn on DCRC1 LED2. Tower → 0.37 K Turn on DCRC3 LED1. Tower → 0.45 K Turn on DCRC3 LED2. Tower → 0.51 K |
| Leave detector baking overnight. | |
| 1710 | Main bath = 49.7% |