| 1005 | Fill LN2 cold trap full. |
| 1030 | G1=123 mbar, G2=131 mbar, P1=240 ubar. Mixing chamber temperature is at 708 mK and has been stable overnight, despite circulating mix. Last time all mix was used to condense (at the time all mix was a G2 pressure of 681 mbar), a base temperature of 87 mK was reached, which corresponded to G1=116 mbar, G2= 103 mbar, and P1=130 ubar. However, this was in old lab, so external bellow volumes have changed. |
| 1045 | Turn on leak checker. Other mixing chamber thermometer reads 706 mK, and cold plate thermometer reads 643 mbar. Notice that 1K Pot is at 1.57 K, so it is possible that the 1K Pot is running dry. Increase 1K Pot temperature to 1.67 K and notice that mixing chamber temperature is dropping. |
| 1115 | Mixing chamber temperature reaches 588 mK and begins to rise. Further open 1K Pot needle valve till 1K Pot temperature reaches 1.71 K. Mixing chamber temperature continues decreasing. |
| 1220 | 1K Pot temperature raised several times with some success. Currently at a 1K Pot temperature of 1.87 K, and the mixing chamber is relatively stable at 396 mK. Still is at 1 K, the cold plate is at 538 mK, and the mixing chamber is at 379 mK. Also G1=208 mbar and G2=211 mbar (much higher than normal). |
| 1315 | Mixing chamber temperature is stable at 382 mK, P1=340 ubar, G1=163 mbar, G2=176 mbar. Perform single shot test. During single shot test DAQ malfunction made it not possible to turn on still heater, resulting in bad test. However, at start of test mixing chamber temperature rose to ~700 mK before dropping about 100 mK and then rising again to ~1 K. Comparing this to overview of potential reasons for high base temperature, it seems that the still is overflowing and there is too much mix present. However, more mix usually means a higher percent of He-3 (as shown in single shot tests performed with 681 mbar, 500 mbar, and 350 mbar worth of mix). It is hard to say whether this single shot test showed no significant decrease in mixing chamber temperature (which indicates not enough He-3), or delayed decrease in mixing chamber temperature (which indicates too much He-3). Start recondensing mixture to perform single shot again. |
| 1430 | While we were circulating (after successful condensing), scroll began making much louder noises. There was no change in pressures of P2 (~14 mbar) or P1 (~5 mbar) at this time. |
| 1530 | With mixing chamber temperature of 811 mK, 1K Pot temperature of 1.55 K, P1=22 ubar, G1=89 mbar, G2=107 mbar and P2=4.5 mbar, commence single shot test again. As with initial single shot test, mixing chamber temperature initially rises, after a moment it drops a rather insignificant amount before continuing to rise. Commence pumping mixture to dump. |
| 1730 | Turn off mixing chamber heater. G2=670 mbar and rising, mixing chamber temperature at 9 K. All mixture recovered. Close V6. |
| 1735 | Fill LN2 codl trap full. P1=3 mbar and rising. Start 1 K Pot. |
| 1740 | G1=1.7 mbar, G2=673 mbar, P1=11 mbar and rising slowly (about 2 mbar/min). Mixing chamber temperature is 8.4 K and 1K Pot at 1.75 mbar. We want 350 mbar worth of mixture in system, so we will aim to condenser until 327 mbar is remaining in G2. Start condensing procedure. |
| 1805 | With G2=327 mbar, close V9, thus using 350 mbar worth of mixture to condense and circulate. G1=151 mbar, P1=1000 mbar, 1K Pot temperature of 1.8 K and mixing chamber temperature of 2.2 K. |
| 1810 | Open V12A all the way. Shortly after hear He-3 pump become louder, pressures in G1/G2 around 100 mbar (nothing too large). |
| 1820 | With G1=95 mbar, G2=94 mbar, P1=1000 mbar, 1KPot temperature at 1.814 K and mixing chamber temperature at 2.3 K, begin circulation. Reduce 1K Pot temperature to 1.73 K. |