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2018/07/06 (Friday)

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Setup: DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 → gender changer 3/?/2 → HVConn 1/3/2 → HV 1/2 → DCRC55(1)/DCRC50(3)
0008 Tower = 1.65 K, Condenser = 268 mbar and falling, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=13.6%
0036 Tower = 1.87 K, Condenser = 140 mbar and falling, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=13.8%
0046 Tower = 1.92 K, Condenser = 118 mbar and falling, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=14.2%
0052 Tower = 1.92 K, Condenser = 108 mbar and falling, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=14.4%
0100 Tower = 1.95 K, Condenser = 97 mbar and flattening out, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=14.8%
0108 Tower = 1.92 K, Condenser = 89 mbar, P1 >1000 mbar. Open V6=15.0%
0112 Tower = 1.94 K, Condenser = 84 mbar, P1 >1000 mbar. Open V6=15.2%
0115 Tower = 1.93 K, Condenser = 81 mbar, P1 >1000 mbar. Open V6=15.6%
0120 Tower = 1.93 K, Condenser = 79 mbar, P1 >1000 mbar, 1K Pot = 1.67 K / 45 mbar. Open V6=16.0%
0125 Tower = 1.94 K, Condenser = 76 mbar, P1 >1000 mbar. Open V6=16.4%
0127 Tower = 1.93 K, Condenser = 73 mbar, P1 >1000 mbar. Open V6=17.0%
0130 Tower = 1.94 K, Condenser = 72 mbar, P1 >1000 mbar. Open V6=17.6%
0135 Have been slowly opening V6 further while watching G1/G2. Currently at V6=23% but G1 = 68mbar and falling. P1>1000 mbar.
0138 Finally, at V6=26% G1 rises to 283 mbar. Tower drops to 1.7 K, 1K pot = 1.67 K / 45 mbar
0609 Tower = 1.91 K, Condenser = 95 mbar, P1 >1000 mbar, 1K pot = 1.67 K / 40 mbar. Open V6=27.0%
0630 Tower = 1.62 K and falling, Condenser = 340 mbar and rising, P1 = 200 mbar and falling, 1K pot = 1.67 K / 40 mbar.
0700 Tower = 1.60 K, Condenser = 347 mbar, Still(P1) = 80 mbar, all flat. 1K pot = 1.67 K / 40 mbar (stable). Open V6→37%.
Still pressure falls quickly.
0735 Tower = 0.99 K with small oscillations, Condenser = 436 mbar, Still(P1) = 0.140 mbar.
not good. Tower can't get below 1 K. Still pressure low, probably poor throughput.
0740 Close V13a, open V9, to start pumping to dump. G1/G2 fall.
0745 Increase Still heater 0.1→10 mW. No increase in Still pressure, actually goes down a little.
0745 Open V3. Now pumping both sides of fridge to dump.
0750 Set MC and Still heaters both to 20 mW
0900 Close 1K Pot needle valve and speedivalve
0950 Tower = 7.5 K and warming. G2 (dump) = 717.5 mbar, flat. 1K Pot = 4.3 K. Still = 0.014 mbar, Condenser = 1.3 mbar.
Still thermometer = 60 K(?). Calibration must be no good around 4K.
1000 Fill LN2 cold trap bath
1000 Top off HPGe dewar.
1000 Close V6. Close V12a+speedi, open V13. This lets mix cool in cold trap before letting it back in the fridge.
1005 Open V12a+speedi. This lets mix into fridge (both sides, V3 is open).
1010 Tower = 8.5 K. Turn off MC and Still heaters.
1015 Tower = 8.3 K, Condenser = 579 mbar. Turbo on IVC = 3.0 nbar
1015 Open 1K Pot speedivalve to start pumping on pot. Pot → 1.76 K / 100 mbar, Condenser → 495 mbar, Tower → 8.1 K.
1020 1K Pot → 3.4 K / 0.45 mbar
1020 Open 1K Pot needle valve → 10°. 1K Pot → 2.9 K / 3.2 mbar
Open 1K Pot needle valve → 20°. 1K Pot → 2.6 K / 5.5 mbar
1025 Open 1K Pot needle valve → 30°. 1K Pot → 2.4 K / 11 mbar
1030 Tower = 6.7 K, Condenser = 490 mbar, both falling
1030 Open 1K Pot needle valve → 40°. 1K Pot → 2.1 K / 16 mbar
1035 Open 1K Pot needle valve → 50°. 1K Pot → 1.8 K / 24 mbar
1035 Tower = 3.5 K, Condenser = 433 mbar, both falling
1040 Open 1K Pot needle valve → 60°. 1K Pot → 1.7 K / 36 mbar
1055 Tower = 2.6 K, Condenser = 198 mbar, both falling. 1K Pot = 1.66 K / 34 mbar
1115 Tower = 2.3 K, Condenser = 106 mbar, flattish. 1K Pot = 1.55 K / 9.5 mbar
1115 Close V3 and V9, leaving 82 mbar in the dump.
1120 Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 235 mbar. Tower falls to 2.15 K. Small response in 1K Pot
1125 1K Pot spontaneously jumps → 1.65 K / 34 mbar
1130 V6 → 13.2%. Condenser peaks at 225 mbar. Tower flat at 2.2 K
1145 Stop DAQ programs and turn off DCRCs. Tower temperature doesn't change much.
1150 V6 → 13.5%. Condenser peaks at 460 mbar. Tower → 1.65 K
1215 V6 → 13.8%. Condenser peaks at 505 mbar. Still → 6.5 mbar. Tower → 1.34 K
1240 V6 → 14.2%. Condenser flattens at 495 mbar. Still → 3.0 mbar. Tower → 1.28 K
1305 V6 → 15.0%. Condenser flattens at 515 mbar. Still → 0.75 mbar. Tower → 1.31 K
1320 V6 → 100%. Condenser flattens at 55 mbar. Still → 0.13 mbar. Tower → 0.97 K
1330 Still = 1.40 K / 0.14 mbar. Turn on Still heater to 2 mW. Still → 1.42 K / 0.15 mbar.
1345 Increase Still heater to 5 mW. Still → 1.45 K / 0.17 mbar.
1350 Switch back to Tower thermometer: Tower has fallen to 202 mK! that's a surprise… But it's rising, reaches 210 mK in a few minutes.
1405 Tower = 255 mbar and rising very steadily, strange.
1415 Try lowering Still heat: temperature goes up faster. Try raising Still heat: temperature goes up more slowly.
1420 At Still = 20 mW, Still → 1.55 K / 0.20 mbar. Tower continues to get warmer, now 314 mK
1430 Tower 430 mbar and rising quickly. Modifying still heat doesn't seem to matter much. Condenser = 740 mbar, goes up a bit with still heat applied.
1430 Close V13a, open V9. Now pumping to dump.
1435 Open V5. Now pumping both sides of fridge to dump. Set MC heater to 20 mW. Tower → 1.5 K.
1440 Close 1K Pot needle valve and speedivalve.
1555 Mixture mostly pumped out to dump.
Check contents of warm LN2 Trap 2: 13 mbar. Pump out with 4He pump.
Throughput test procedure, Cold Trap 1:
  1. All mixture in dump, LN2 traps cold, condenser & still valves open (3He pump on - optional)
  2. Open V9, V13a, V12a+speedivalve, V3. Wait for G1 to be close to G2.
  3. Close V12a+speedivalve and V3, open V1
  4. monitor G1
1610 Perform mixture throughput test at MC = 9.8 K using above procedure with 3He pump on. Let G1 rise to 560 mbar before Step 3, then it falls to 240 mbar and starts to rise. Throughput = 116 mbar/min.
Is this good? Certainly is not zero. It's more than twice a typical 77K rate. Not sure what it should be at 10K.
1630 Turn off MC and Still heaters
1635 Open 1K Pot speedivalve to start pumping on pot. Pot → 1.9 K / 400 mbar, then → 4.0 K / 0.95 mbar
Open 1K Pot needle valve → 15°. 1K Pot → 3.2 K / 4.5 mbar
1640 Open 1K Pot needle valve → 30°. 1K Pot → 2.6 K / 12 mbar
Open 1K Pot needle valve → 45°. 1K Pot → 2.1 K / 24 mbar
1645 Open 1K Pot needle valve → 60°. 1K Pot → 1.7 K / 50 mbar
1700 Tower = 2.95 K, Condenser = 300 mbar, both falling
1705 Started to pump mixture to dump to try another throughput test. But mixture is partly condensed so this won't work. Open mixture to fridge again.
1710 Fill LN2 cold trap bath.
1720 Tower = 2.53 K, Condenser = 131 mbar, both falling. 1K Pot = 1.67 K / 40 mbar, falling ever since returning the mixture (which caused a spike)
1730 Tower = 2.3 K, Condenser = 84 mbar, both falling. 1K Pot = 1.61 K / 22 mbar
Open 1K Pot needle valve → 70°. 1K Pot → 1.62 K / 24 mbar
1735 Open 1K Pot needle valve → 80°. 1K Pot → 1.62 K / 24 mbar
shortly after it spikes → 1.74 K / off scale
1740 Close 1K Pot needle valve → 70°. 1K Pot → 1.72 K / 200 mbar
1745 Close 1K Pot needle valve → 65°. 1K Pot → 1.71 K / 100 mbar
1730 Tower = 2.1 K, Condenser = 81 mbar
1820 Tower = 2.0 K, Condenser = 68 mbar, 1K Pot = 1.71 K / 100 mbar
Close V3. Close V9 leaving 47 mbar of mixture in dump.
1820 Start circulation through Trap 1. V6 → 12.8%. Condenser peaks at 145 mbar.
1830 V6 → 13.2%. Condenser peaks at 195 mbar. Tower → 1.8 K
1930 Tower = 1.7 K. Condenser = 127 mbar and falling.
2140 Tower = 1.7 K. Condenser = 67 mbar and falling.
2300 Tower = 1.8 K. Condenser = 60 mbar.
V6 → 13.6%. Looks like the condenser will peak around 350 mbar.

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