2019/04/29 (Monday)
| Status | Discovered a blockage Friday. Warming up. Mixture has been cleaned 6 times. Left mixture cooling in LN2 Cold Trap 2 over the weekend. Removed 5.6 mbar |
|---|---|
| Setup | DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 |
| 0855 | Turbo on cryostat vacuum jacket = 16 nbar. With pump valved out vacuum jacket = 250 nbar. MC(Cernox) = 290.5 K |
| 0855 | DIB4pD SQUID is reading OK, 3.293 kOhm |
| 0900 | Pump mixture out of LN2 Cold Trap 2 to dump. |
| 0910 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 13.1% |
| 0930 | Start pumping out IVC with scroll pump. After a couple of minutes switch to turbo pump. |
| 0915 | Increase V6 → 13.2% to speed up flow |
| 0940 | Increase V6 → 13.3% to speed up flow |
| 1010 | Stop cleaning through Trap 1 after 60 min. G2 flow pressure was 580-820 mbar. Pump mixture to dump. Removed 15.8 mbar. That's significantly higher. Maybe because I circulated at significantly higher pressure? |
| 1020 | LN2 Trap 2 is mostly warm. Check contents: 6.9-1.3 = 5.6 mbar on G1. Pump out with scroll pump. |
| 1035 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 13.0% |
| 1040 | Increase V6 → 13.1% to restart flow |
| 1045 | Increase V6 → 13.2% to speed up flow |
| 1050 | Increase V6 → 13.3% to speed up flow |
| 1135 | Stop cleaning through Trap 2 after 60 min. G2 flow pressure was 575-830 mbar. Pump mixture to dump. Removed 3.9 mbar |
| 1150 | LN2 Trap 1 is mostly warm. Check contents: 17.3-1.5 = 15.8 mbar on G1. Pump out with scroll pump. |
| 1210 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.9% |
| 1220 | Increase V6 → 13.0% to speed up flow |
| 1245 | Increase V6 → 13.1% to speed up flow |
| 1310 | Stop cleaning through Trap 1 after 60 min. G2 flow pressure was 580-700 mbar. Pump mixture to dump. Removed 7.2 mbar |
| 1330 | LN2 Trap 2 is mostly warm. Check contents: 5.3-1.4 = 3.9 mbar on G1. Pump out with scroll pump. |
| 1345 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.9% |
| 1405 | Increase V6 → 13.1% to speed up flow |
| 1425 | Increase V6 → 13.2% to speed up flow |
| 1500 | Stop cleaning through Trap 2 after 75 min. G2 flow pressure was 575-620 mbar. Pump mixture to dump. Removed 4.1 mbar |
| 1520 | LN2 Trap 1 is mostly warm. Check contents: 8.7-1.5 = 7.2 mbar on G1. Pump out with scroll pump. |
| 1600 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 13.0% |
| 1630 | Increase V6 → 13.3% to speed up flow |
| 1640 | Increase V6 → 13.4% to speed up flow |
| 1650 | Stop cleaning through Trap 1 after 50 min. G2 flow pressure was 575-790 mbar. Pump mixture to dump. Removed 6.5 mbar |
| 1705 | LN2 Trap 2 is mostly warm. Check contents: 5.4-1.3 = 4.1 mbar on G1. Pump out with scroll pump. |
| 1710 | Close v9 then turn off 3He pump, isolating pump from dump. Open dump through v4 and v12B+speedivalve to cold LN2 Trap 2 to cool overnight. |