| 0850 | Dump reads 794.1 mbar at G2. Pbar = 30.12“Hg, corrected dump pressure = 800.9 mbar |
|---|---|
| Main bath 61.4%. MC 7.1 K on Cernox thermometer, peaked at 7.3 K overnight | |
| Turbo on IVC reads 1.9e-6 mbar. IVC reads 1.4e-5 mbar with turbo valved out | |
| 0920 | Warm up cold traps and pump them out. T1 had 40.0 mbar, T2 had 8.0 mbar, both read at P2. Pumped each down to 0.024 mbar |
| 0950 | Letting mixture into fridge before starting 1K Pot (to look at temperatures) |
| G2 (dump) starts at 795. Trickle mix into fridge through trap and closed V12A | |
| Before starting, MC (H35) = 7.1 K, Still (U02844) = 9.1 K | |
| When mix goes in, MC heats to 7.35 K and flattens. Still increases to 9.4 K but then steadily falls | |
| this suggests that overnight the still gets somewhat warmer than the bath due to conduction from the top. When mix is introduced it is cooled by the bath above the IVC, and the still gets cooler as it approaches equilibrium with the bath. | |
| 1017 | Still (U02844) = 7.7 K |
| 1022 | Still (U02844) = 7.2 K, below MC which is at 7.35 K. 1K Pot temperature falls to 6.5 K |
| 1025 | G2=602 mbar (dump slowly emptying), G1 = 385 mbar (mix entering fridge) |
| 1030 | Still (U02844) = 6.73 K, MC = 7.28 K (slowly cooling now), 1K Pot = 6.27 K |
| 1037 | Still (U02844) = 6.38 K, MC = 7.20 K, 1K Pot = 6.09 K. G2 = 578 mbar, G1 = 451 mbar |
| 1051 | Still (U02844) = 6.00 K, MC = 7.05 K, 1K Pot = 5.90 K. G2 = 578 mbar, G1 = 451 mbar |
| 1103 | Still (U02844) = 5.85 K, MC = 6.93 K, 1K Pot = 5.84 K. G2 = 552 mbar, G1 = 522 mbar |
| 1107 | Start 1K Pot, needle valve open slightly, 4.0 mbar. 1K Pot falls from 5.8 K to 3.1 K, Still falls from 5.8 K to 3.3 K, G2 falls from 530 mbar to 440 mbar. |
| 1124 | Open needle valve in small steps. 1K Pot at 2.2 K / 8.0 mbar. MC plummets to 3.0 K. Still 2.6 K and falling. G1 235 mbar and falling. G2 (dump) 522 mbar, slowly falling. |
| 1133 | Open V12a to 2%. Temperatures go up a bit, G2 starts rising, G1 falls faster. |
| 1139 | G2 = 414 mbar, G1 = 174 mbar |
| 1147 | Still (U02844) = 2.53 K, MC = 2.55 K, 1K Pot = 2.05 K / 12 mbar. G2 = 321 mbar, G1 = 181 mbar and falling again |
| 1155 | Still (U02844) = 2.15 K, MC = 2.30 K, 1K Pot = 1.66 K / 12 mbar. G2 = 249 mbar, G1 = 106 |
| 1206 | Still (U02844) = 1.88 K, MC = 2.02 K, 1K Pot = 1.62 K / 8.5 mbar. G2 = 165 mbar, G1 = 65 |
| 1230 | open V12A full |
| 1236 | forgot to isolate IVC from turbo pump, doing so now |
| 1245 | Still (U02844) = 1.61 K, MC = 1.66 K, 1K Pot = 1.55 K / 5.0 mbar. G2 = 34 mbar, G1 = 34 mbar (note we have now let in almost all the mix) |
| 1248 | Begin circulation |
| tried the standard throttling of V6 to control G1/G2 but had trouble, oscillatory behavior in still temp and pressures, hard to get P1 to come down except very briefly | |
| after a while opened V6 wide, and finally saw still temperature fall below 1.3 K and fall to 0.75 K. 1K pot had trouble at first, pressure at P2 maxed out, but after a few minutes everything looked good. | |
| 1343 | MC = 0.218 K, Still (U02844) = 0.846 K, 1K Pot = 1.56 K / 5.0 mbar. G1 = 86 mbar, G2 = 93 mbar |
| 1351 | MC = 0.112 K, Still (U02844) = 0.956 K / 0.10 mbar, 1K Pot = 1.59 K / 6.0 mbar. G1 = 84 mbar, G2 = 80 mbar |
| 1357 | MC = 60.0 mK, Still (U02844) = 0.950 K / 0.085 mbar, 1K Pot = 1.65 K / 12 mbar. G1 = 87 mbar, G2 = 84 mbar |
| 1404 | MC = 39.2 mK, Still (U02844) = 0.962 K / 0.065 mbar, 1K Pot = 1.64 K / 9.5 mbar. G1 = 77 mbar, G2 = 75 mbar |
| 1515 | G1=71 mbar, G2=72 mbar, P1=60 ubar, and mixing chamber temperature at 29 mK and stable. Open V14 to bleed out remaining mix from dump. P1 rose to 36 mbar and begun to drop. |
| 1537 | Close V14, with mixing chamber temperature at 33mK. |
| 1633 | MC = 28.3 mK, Still (U02844) = 0.951 K / 0.085 mbar, 1K Pot = 1.65 K / 12.0 mbar. G1 = 67 mbar, G2 = 66 mbar. Fridge quite stable. |
| Applied still heat for the purpose of recalibrating the still thermometer. As with the last run, heating the still did not improve the base temperature. | |
| 1800 | Recovering mix to dump. |
| 2040 | Recovered 799 mbar dump pressure of mixture. Turn off all heaters and close all valves - stop mixture recovery. |
| Pbar = 30.02”Hg, corrected dump pressure = 802.4 mbar |