| 0825 | Fill cold trap with LN |
|---|---|
| 0830 | Dump = 806.7 mbar @ G2 |
| MC = 6.72 K. Drifted up from 6.1 K over last 12 hours. Main bath at 71.7%. | |
| Turbo pump pressure reads 1e-8 mbar, both with pump valve open and closed. | |
| 0840 | Begin cleaning mixture through Trap 2. V6 open 12.8%. |
| 0847 | G1/G2 = 690/630 mbar. Increase V6 to 13.2% |
| 0853 | Tube from trap a bit frosty, reduce V6 to 13.0 % |
| 0857 | MC = 6.75 K (Cernox), Still thermometer = 2.5434 kOhm |
| 0913 | G1/G2 = 694/661 mbar |
| 0917 | Stop cleaning mixture. Pump mixture to dump. |
| 0937 | Dump = 807.5 mbar @ G2 |
| 0939 | Start 1K Pot |
| 0946 | Begin condensing mixture |
| 1016 | Open V12 fully. Currently mixing chamber temperature is at 2.5 K, G1=179 mbar, G2=202 mbar, and 1K Pot is at 1.8 K. |
| 1026 | With mixing chamber temperature at 2.1 K, G1= 86 mbar, and G2=105 mbar, close V9 and commence circulation procedure. |
| 1036 | MC = 1.75 K (H35), Still thermometer = 3.693 kOhm |
| 1058 | Open V6 completely. Mixing chamber temperature at 800 mK, G1=132 mbar, G2=164 mbar. |
| 1121 | MC = 35.5 mK !! you read that right !! Still = 1.18 K |
| 1126 | MC = 31 mK, G1/G2 = 74/89 mbar, Still = 0.095 mbar / 1.17 K, 1K Pot = 1.82 K / 90 mbar |
| 1136 | MC = 27 mK |
| 1140 | MC = 30 mK |
| 1144 | close pot needle valve somewhat |
| 1146 | MC = 25 mK, G1/G2 = 67/82 mbar, Still = 0.075 mbar, 1K Pot = 1.73 K / 24 mbar |
| 1152 | MC = 24.7 mK, G1/G2 = 59/75 mbar, Still = 0.065 mbar / 1.11 K, 1K Pot = 1.68 K / 12 mbar |
| 1200 | MC = 24.3 mK |
| 1201 | apply 1 mW to still |
| 1204 | MC = 24.2 mK, G1/G2 = 63/78 mbar, Still = 0.080 mbar / 1.11 K, 1K Pot = 1.67 K / 12 mbar |
| 1205 | increase still heat to 2 mW |
| 1212 | MC = 24.0 mK, G1/G2 = 66/82 mbar, Still = 0.095 mbar |
| 1213 | increase still heat to 4 mW. base goes up to 24.2 mK then back down a bit |
| 1218 | MC = 24.1 mK, G1/G2 = 69/88 mbar, Still = 0.120 mbar |
| 1221 | increase still heat to 8 mW. base rises to 25 mK and flattens |
| 1225 | MC = 25.0 mK, G1/G2 = 73/96 mbar, Still = 0.170 mbar |
| 1226 | reduce still heat to 2 mW |
| 1259 | MC = 24.9 mK. Turn off still heat and prepare to add remaining mixture (about 100 mbar is still in the dump) |
| Lakeshore bridge settings: range 200 kOhm, excitation 20 uV, power 1.65 fW; voltage mode | |
| 1305 | MC = 23.8 mK, still = 0.065 mbar. Begin adding more mix through V14 |
| Opened V14 until P1 read 1000 mbar then closed again. MC rose to 52 mK and began dropping again. | |
| G2 rose by 50 mbar while mix was being added. This may be an indication of how much mixture was removed from dump. | |
| 1318 | MC bottoms out at 26.7 mK. so not as good as before. Actually not bottomed out - starts creeping down again… |
| 1334 | MC = 24.4 mK, G1/G2 = 60/74 mbar, Still = 0.100 mbar (0 mW), 1K Pot = 1.67 K / 12 mbar |
| 1356 | MC = 23.7 mK, G1/G2 = 59/74 mbar, Still = 0.100 mbar (0 mW), 1K Pot = 1.67 K / 12 mbar |
| 1410 | MC = 23.5 mK |
| 1412 | apply 2 mW to still. Base goes up to 23.6 mK then back down to 23.5 mK |
| 1420 | MC = 23.5 mK, G1/G2 = 66/83 mbar, Still = 0.130 mbar / 2 mW, 1K Pot = 1.67 K / 12 mbar |
| 1430 | MC climbs a bit, to 23.7 mK |
| Opened V14 until P1 read 1000 mbar then closed again. MC rose to 45 mK and began dropping again. | |
| G2 rose by 35 mbar while mix was being added. | |
| 1444 | MC drops to 25 mK then bounces up a bit, similar pattern to last time we added mix |
| 1447 | Letting the rest of the mix in. Leaving V14 open. G2 rose a total of 70 mbar during the process of adding mix. |
| 1451 | MC peaks at 116 mK then falls again |
| 1519 | P1 at 0.6 mbar, close V16. MC = 29 mK |
| 1525 | MC = 27.5 mK, G1/G2 = 61/75 mbar, Still = 0.100 mbar (0 mW), 1K Pot = 1.67 K / 11 mbar |
| 1547 | MC = 23.7 mK, G1/G2 = 61/76 mbar, Still = 0.100 mbar (0 mW), 1K Pot = 1.68 K / 12 mbar |
| 1600 | MC = 23.5 mK |
| Note: MC temperatures quoted here are read off the LabVIEW VI, which uses the functional form fit | |
| … the LakeShore Bridge display, based on the raw data, does not exactly agree | |
| … currently for example the LabVIEW reads 23.4 mK, LakeShore reads 23.8 mK | |
| 1617 | MC = 23.4 mK, G1/G2 = 61/76 mbar, Still = 0.100 mbar (0 mW), 1K Pot = 1.68 K / 12 mbar |
| 1631 | MC = 23.3 mK. Fill LN2 cold trap full. |
| 1708 | Mixing chamber stable at 23.3 MK, P1=100 ubar, G1=61 mbar, G2= 76 mbar, 1K Pot steady at 1.67 K, and P2=12 mbar. Turn on Still heater to 2 mW. |
| 1940 | Mixing chamber temperature has stabilised at 23.5 mK after a couple of oscillations, and has remained at this temperature for a couple of hours. Pressures in P1, G1 & G2 are 140 μbar, 67 mbar & 82 mbar respectively. Temperature of 1 K pot steady at 1.67 K and pressure in P2 is 11 mbar. Turn off still heater. Wait for fridge to recover. |
| 2230 | Mixing chamber temperature has stabilised at 23.1 mK. Pressures in P1, G1 & G2 are 100 μbar, 61 mbar & 69 mbar respectively. Temperature of 1 K pot steady at 1.67 K and pressure in P2 is 12 mbar. Commence incrementing power to mixing chamber heater and recording effect on temperature. Start with power of 2 μW. |
| 2355 | Mixing chamber temperature appears to have stabilised at 24.9 mK. That took a while. That probably isn't completely unexpected - the fridge appears to be behaving as she should. Turn off mixing chamber heater. We may continue test tomorrow. |