| 0902 | Pumped remainder of gas in fridge to dump. G2 = 746.3 mbar. |
|---|---|
| corrected for barometric pressure, dump = 748 mbar. | |
| 0915 | Filled cold trap |
| 1000 | Add more He gas to mixture until dump pressure = 798.2mbar. |
| 1030 | Remove LN2 cold traps from bath to see how much dirt was collected during cryocleaning and circulation yesterday. |
| 1115 | 3.5mbar collected from both cold traps, indicating very little contamination. Pump out cold traps. |
| 1135 | Isolate cold traps and place back in LN2 bath. Fill LN2 codl trap full. Start condensing through cold trap 1 with G2=795.5 mbar. |
| 1155 | Start 1K Pot (oops). |
| 1239 | Open V12A fully. |
| 1255 | Commence circulation procedure. G1=79 mbar, G2=65 mbar, MC=2.1 K. |
| 1415 | Close V14 with P1=0.7 mbar. |
| 1420 | MC = 840? mK, Still = 847 mK, G1/G2/P1 = 145 / 146 / 0.14 mbar, 1KPot = 1.74 / 34 mbar |
| 1427 | MC = 1.05? mK, Still = 832 mK, G1/G2/P1 = 110 / 105 / 0.13 mbar, 1KPot = 1.68 / 17 mbar |
| 1433 | Still heat 0.5 mW, Still 740 mK, MC 763 mK, 1KPot 1.68 K, G1=122 mbar, G2=118 mbar, P1=0.11 mbar, P2=16 mbar |
| 1438 | Still heat 2.0 mW, Still 885? mK, MC 974 mK, 1KPot 1.68 K, G1=125 mbar, G2=121 mbar, P1=0.16 mbar, P2=16 mbar |
| oops - I think I've been using the wrong calibration for the still temperatures. The values with question marks are my attempts to correct the wrong ones. | |
| 1446 | Still heat 4.0 mW, Still 919? mK, MC 775 mK, 1KPot 1.68 K, G1=133 mbar, G2=131 mbar, P1=0.2 mbar, P2=16 mbar |
| 1438 | Still heat 8.0 mW, Still 973? mK, MC 574 mK, 1KPot 1.68 K, G1=128 mbar, G2=133 mbar, P1=0.26 mbar, P2=16 mbar |
| 1501 | Still heat 8.0 mW, Still 1.02 K, MC 384 mK, 1KPot 1.68 K, G1=125 mbar, G2=130 mbar, P1=0.28 mbar, P2=16 mbar |
| 1521 | Still heat 20.0 mW, Still 1.20 K, MC 311 mK, 1KPot 1.68 K, G1=164 mbar, G2=174 mbar, P1=0.40 mbar, P2=16 mbar |
| 1531 | Still heat 24.0 mW, Still 1.21 K, MC 306 mK, 1KPot 1.67 K, G1=189 mbar, G2=198 mbar, P1=0.40 mbar, P2=17 mbar |
| 1551 | Still heat 28.0 mW, Still 1.25 K, MC 304 mK, 1KPot 1.68 K, G1=227 mbar, G2=233 mbar, P1=0.45 mbar, P2=18 mbar |
| 1602 | Still heat 32.0 mW, Still 1.28 K, MC 301 mK, 1KPot 1.69 K, G1=259 mbar, G2=261 mbar, P1=0.50 mbar, P2=20 mbar |
| 1613 | Still heat 36.0 mW, Still 1.30 K, MC 299 mK, 1KPot 1.66 K, G1=266 mbar, G2=269 mbar, P1=0.55 mbar, P2=14 mbar |
| 1630 | Hit a minimum of 295 mK at 40 mW still heat. But G1 & G2 pressures started to run away, and the 1KPot started to struggle, so I dialed the heat back down. |
| 1647 | Performed a brief one-shot to remove some mix. Intended to remove around 40 mbar of the ~160 mbar of 3He that we think we have, but hard to control this. After the fact we found that we had removed 49.5 mbar. During this time the MC crept up to around 330 mK. Then we tried circulating again. |
| 1711 | MC = 300 mK, Still heater @ 44 mW, G1/G2/P1 = 191 / 215 / 0.60 mbar |
| 1719 | MC = 298 mK, Still heater @ 55 mW, G1/G2/P1 = 221 / 247 / 0.75 mbar |
| Achieved a minimum of 297 mK with the still heater at 60 mW, G1&G2 at 330 mbar, P1 at 0.90 mbar. At this point further heating of the still did not produce any improvement in the MC temperature. So it seems that with 49.5 mbar of 3He removed, we could turn the still heat much higher without causing runaway pressures, but we were not able to achieve a better base temperature. | |
| 1737 | Stopped 1KPot, begin recovery. Turned on MC heater. |