2017/11/16 (Thursday)
| Initial LHe transfer yesterday. Pumping IVC overnight. Mixture open from dump to fridge through (cold) Trap 2. | |
| 0920 | Tower/Sorb/1K Pot = 4.66/8.2/6.36 K, G1(fridge) = 551.8 mbar, Turbo(on IVC) = 1.4 nbar, IVC = 12 nbar, MB = 72.2% Stop pumping on IVC |
| 0925 | Fill LN2 cold trap bath |
| 0930 | Pump out line leading to 1K Pot, then open 1K Pot speedivalve. (Note that 1K Pot was evacuated before LHe transfer and needle valve was closed.) About 0.25 bar in 1K Pot. Pot temperature dips to 4.5 K when valve opened, then rises again. Pump out for a few seconds with scroll pump, then switch to 4He pump. Open the two valves to connect 4He exhaust to recovery. |
| 0935 | 1K Pot = 6.38 K / 0.38 mbar Open 1K Pot Needle Valve to ~10 degrees. 1K Pot → 3.3 K / 3.2 mbar |
| 0940 | Open Needle Valve a few more degrees. 1K Pot → 3.1 K / 4.0 mbar Open Needle Valve a few more degrees. 1K Pot → 2.9 K / 4.5 mbar |
| 0945 | Open Needle Valve a few more degrees. 1K Pot → 2.6 K / 7.5 mbar |
| 0950 | Tower temp and Fridge pressure falling. Tower = 3.30 K, G1(fridge) = 425.0 mbar |
| 0955 | Open Needle Valve a few more degrees. 1K Pot → 2.4 K / 15 mbar Open Needle Valve a few more degrees. 1K Pot → 1.8 K / 30 mbar |
| 1000 | Open Needle Valve a few more degrees. 1K Pot → 1.7 K / 38 mbar |
| 1010 | Tower = 2.62 K (falling), 1K Pot = 1.66 K, Fridge(G1) = 173 mbar (falling) |
| 1015 | Tower = 2.38 K (falling), 1K Pot = 1.63 K, Fridge(G1) = 111 mbar (falling) |
| 1020 | Tower = 2.17 K (falling), 1K Pot = 1.58 K, Fridge(G1) = 75 mbar (falling) |
| 1020 | 1K Pot = 1.58 K / 13 mbar, pressure steadily falling. Open Needle Valve a few more degrees. 1K Pot → 1.58 K / 13 mbar, flattening out |
| 1025 | Open Needle Valve a few more degrees. 1K Pot → 1.62 K / 24 mbar |
| 1030 | Tower = 2.09 K (flattening), 1K Pot = 1.58 K, Fridge(G1) = 62.3 mbar (flattening) |
| 1030 | 1K Pot surge, pressure on P2 goes off-scale, temperature → 1.79 K. Pressure on mechanical gauge is around 1 “Hg, which is only around 35 mbar. |
| 1035 | 1K Pot pressure on P2 is still maxed out, temperature steady. Close Needle Valve a few degrees. Pressure oscillates strongly. |
| 1040 | 1K Pot = 1.73 K, 600±300 mbar. Tower temperature was flat but now begins to fall again. |
| 1045 | Tower = 2.02 K, Fridge(G1) = 61.4 mbar, 1K Pot = 1.73 K, 500±100 mbar |
| The 1K Pot surge happened at about the same temperature as in Run 65. After the surge the Tower temperature fell from 2.09 K to 2.02 K (flat before and after). Looks like some sort of phase transition… Looks like it also happened in Run 64, Run 63, Run 61. 2.17 K is the lambda point of LHe. |
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| 1050 | Tower = 2.02 K (flat), Fridge(G1) = 59.7 mbar (falling slowly), 1K Pot = 1.73 K / 400±100 mbar |
| 1100 | Tower = 2.00 K (flat), Fridge(G1) = 58.0 mbar (falling slowly), 1K Pot = 1.73 K / 400±100 mbar |
| 1110 | Tower = 1.95 K (falling), Fridge(G1) = 57.2 mbar (falling more slowly), 1K Pot = 1.73 K / 300±100 mbar |
| 1120 | Tower = 1.93 K (flattening), Fridge(G1) = 56.1 mbar (falling slowly), 1K Pot = 1.73 K / 300±50 mbar |
| 1145 | Tower = 1.90 K (falling slowly), Fridge(G1) = 53.8 mbar (falling slowly), 1K Pot = 1.72 K / 250±50 mbar |
| 1145 | Close V9 leaving 53.4 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. |
| 1300 | Tower = 1.87 K (flattish), Fridge(G1) = 48.3 mbar (falling slowly), 1K Pot = 1.72 K / 175±25 mbar |
| 1305 | Start circulation through Trap 2. V6 → 12.8%. Condenser peaks at 130 mbar. 1K Pot pressure spikes off scale then falls. Tower falls to 1.7 K. |
| 1315 | V6 → 13.2%. Condenser peaks at 121 mbar. Tower → 1.57 K. |
| 1320 | V6 → 13.5%. Condenser peaks at 134 mbar. Tower → 1.48 K. |
| 1324 | MC(H35)/Coldplate/Still = 1.42/2.16/1.75 K |
| 1335 | V6 → 13.8%. Condenser peaks at 143 mbar. Still → 15 mbar. Tower → 1.29 K. (Cools to about 1.1 K then flattens abruptly) |
| 1345 | V6 → 14.2%. Condenser rises to 137 mbar and flattens. Still → 3.8 mbar. Tower → 1.12 K (kinda flat). |
| 1349 | MC(H35)/Coldplate/Still = 920 mK/875 mK/1.26 K |
| 1400 | V6 → 15.0%. Condenser peaks at 145 mbar. Still → 1.6 mbar. Tower → 590 mK (and falling). |
| 1405 | 1K Pot = 1.71 K / 150±20 mbar |
| 1410 | Condenser has fallen to 136 mbar. Still = 1.1 mbar. |
| 1410 | V6 → 100%. Condenser peaks at 142 mbar. Still → 0.19 mbar. Tower → 160 mK (and falling). |
| 1415 | MC(H35)/Coldplate/Still = 133 mK/270 mK/1.31 K |
| 1420 | Tower = 100 mK |
| 1422 | He recovery meter = 111200 cuft |
| 1425 | Tower/MC/Coldplate = 65/51/163 mK, Still = 1.24 K / 0.150 mbar, G1/G2 = 113/105 mbar, 1K Pot = 1.72 K / 150±20 mbar. |
| 1440 | Tower/MC/Coldplate = 44.0/37.6/161 mK, Still = 1.32 K / 0.120 mbar, G1/G2 = 92/86 mbar, 1K Pot = 1.71 K / 150±20 mbar. |
| 1445 | Open V14 to let the rest of the mixture from the trap into circulation. Condenser peaks at 128 mbar, Still peaks at 150 mbar, MC rises to 99 mK then falls again. |
| 1500 | Tower/MC/Coldplate = 55.4/46.0/163 mK, Still = 1.28 K / 1.8 mbar (V14 open), G1/G2 = 80/76 mbar, 1K Pot = 1.71 K / 150±20 mbar. |
| 1515 | Tower/MC/Coldplate = 41.1/31.6/157 mK, Still = 1.25 K / 0.55 mbar (V14 open), G1/G2 = 87/81 mbar, 1K Pot = 1.71 K / 135±15 mbar. |
| 1520 | Still = 0.50 mbar. Close V14. |
| 1530 | Tower/MC/Coldplate = 38.8/29.4/161 mK, Still = 1.4 K / 0.120 mbar, G1/G2 = 88/82 mbar, 1K Pot = 1.71 K / 135±15 mbar. |
| 1618 | Tower/MC/Coldplate = 37.7/28.6/154 mK, Still = 1.26 K / 0.120 mbar, G1/G2 = 89/84 mbar, 1K Pot = 1.71 K / 130±20 mbar. |
| 1648 | Fill LN2 cold trap full. |