2019/05/14 (Tuesday)
| Status | Warm after hitting fridge blockages, 3 times. Cryostat vacuum jacket and IVC both pumped out. |
|---|---|
| Setup | DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2 |
| 0830 | Fill LN2 cold trap bath |
| 0830 | Mixture has been open to cold LN2 Trap 1 overnight. Pump mixture out of Trap 1 into dump. Removed 10.4 mbar. this is still pretty high… |
| 0845 | LN2 Trap 2 is warm. Check contents: 13.2-1.4 = 11.8 mbar on G1. Pump out with scroll pump. |
| 0855 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.4% |
| 0900 | Increase V6 → 12.9% to restart flow. G1 increases by ~15 mbar as G2 rises. |
| 1000 | Stop cleaning through Trap 2 after 65 min. G2 flow pressure was 570-680 mbar. Pump mixture to dump. Removed 5.1 mbar. |
| 1010 | LN2 Trap 1 is mostly warm. Check contents: 12.1-1.7 = 10.4 mbar on G1. Pump out with scroll pump. |
| 1020 | Check fridge pressures: LHe trap/Condenser/Still = 1.8/0.3/0.12 mbar. Pump out with scroll pump. |
| 1035 | Pump fridge down lower by pumping it to the dump with the 3He pump. Scroll pump through V2 only got Still down to 0.14 mbar - pumping with 3He pump through V6 gets it down to 0.02 mbar. |
| Change of procedure: we'll try waiting before introducing the mixture into the fridge. Cool to 77K with fridge empty. | |
| 1045 | With 1K Pot speedivalve and needle valve closed, pump on Main bath with scroll pump. Once P2 < 100 mbar, open 1K pot speedivalve and needle valve (5 turns) to pump out 1K pot volume to < 1 mbar on P2. |
| 1100 | Close off scroll pump, then pressurized bath and 1K Pot (both sides) to about 0.5 bar with helium. Then pump it out again with scroll pump to < 1 mbar. |
| 1110 | Pressurize main bath and 1K Pot (both sides) to 375 mbar +1atm on G3, then close 1K Pot speedivalve and needle valve. |
| 1110 | Turbo on IVC = 10 nbar. With turbo valved out for a few minutes, IVC = 190 nbar. |
| 1115 | Let 5.4 mbar He exchange gas into IVC |
| 1115 | MC(Cernox) = 292.3 K, Sorb = >249 K (max), IVC = 5.4 mbar, Level resistor = 0.986 kΩ. DIB4 pD SQUID = 3.312 kΩ. |
| 1120 | Begin LN2 transfer |
| 1120 | LN2 Trap 2 is mostly warm. Check contents: 5.8-0.7 = 5.1 mbar on G1. Pump out with scroll pump. |
| 1130 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.9% |
| 1135 | MC(Cernox) = 291.8 K, Sorb = >249 K (max), IVC = 4.6 mbar, Level resistor = 0.993 kΩ. DIB4 pD SQUID = 3.266 kΩ. |
| 1135 | Increase V6 → 13.1% to restart flow. G1 falls by ~5 mbar as G2 rises. |
| 1145 | Increase V6 → 13.2% to restart flow. G1 falls by ~2 mbar as G2 rises. |
| 1150 | MC(Cernox) = 280.3 K, Sorb = >249 K (max), IVC = 4.0 mbar, Level resistor = 1.006 kΩ. DIB4 pD SQUID = 2.909 kΩ. |
| 1205 | MC(Cernox) = 262.5 K, Sorb = >249 K (max), IVC = 3.4 mbar, Level resistor = 1.010 kΩ. DIB4 pD SQUID = 2.593 kΩ. |
| 1215 | Increase V6 → 13.3% to restart flow. G1 falls by ~4 mbar as G2 rises. |
| 1220 | MC(Cernox) = 238.2 K, Sorb = >249 K (max), IVC = 3.0 mbar, Level resistor = 1.027 kΩ. DIB4 pD SQUID > 10 kΩ, unstable. |
| 1230 | Stop cleaning through Trap 1 after 60 min. G2 flow pressure was 575-645 mbar. Pump mixture to dump. Removed 4.2 mbar. |
| 1235 | MC(Cernox) = 214.5 K, Sorb = >249 K (max), IVC = 2.5 mbar, Level resistor = 1.050 kΩ. DIB4 pD SQUID = 2.15 kΩ. |
| 1250 | Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 13.2% |
| 1250 | MC(Cernox) = 190.3 K, Sorb = >249 K (max), IVC = 2.5 mbar, Level resistor = 1.088 kΩ. DIB4 pD SQUID = 3 kΩ, unstable. |
| 1255 | Increase V6 → 13.3% to restart flow. |
| 1305 | MC(Cernox) = 167.5 K, Sorb = >249 K (max), IVC = 2.2 mbar, Level resistor = 1.137 kΩ. DIB4 pD SQUID = 1.775 kΩ. |
| 1310 | Increase V6 → 13.4% to speed up flow. G1 rises by ~1.5 mbar as G2 rises. |
| 1325 | MC(Cernox) = 142.3 K, Sorb = 247.7 K, IVC = 1.9 mbar, Level resistor = 1.221 kΩ. DIB4 pD SQUID = 1.9 kΩ, unstable. |
| 1335 | MC(Cernox) = 131.7 K, Sorb = 213.3 K, IVC = 1.9 mbar, Level resistor = 1.255 kΩ. DIB4 pD SQUID = 1.618 kΩ. |
| 1350 | MC(Cernox) = 121.0 K, Sorb = 179.9 K, IVC = 1.9 mbar, Level resistor = 1.282 kΩ. DIB4 pD SQUID = 1.563 kΩ. |
| 1355 | Stop cleaning through Trap 2 after 65 min. G2 flow pressure was 570-600 mbar. Pump mixture to dump. Removed 2.4 mbar. |
| 1405 | MC(Cernox) = 113.4 K, Sorb = 159.1 K, IVC = 1.6 mbar, Level resistor = 1.299 kΩ. DIB4 pD SQUID = 5 kΩ, unstable. |
| 1410 | LN2 Trap 1 is mostly warm. Check contents: 5.8-1.6 = 4.2 mbar on G1. Pump out with scroll pump. |
| 1415 | Pack up S101 to send to Rupak for re-fabrication. |
| 1420 | MC(Cernox) = 106.2 K, Sorb = 143.5 K, IVC = 1.6 mbar, Level resistor = 1.312 kΩ. DIB4 pD SQUID = 1.441 kΩ. |
| 1430 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 13.2% |
| 1435 | MC(Cernox) = 100.5 K, Sorb = 134.8 K, IVC = 1.6 mbar, Level resistor = 1.321 kΩ. DIB4 pD SQUID = 1.412 kΩ. |
| 1440 | End LN2 transfer. Put ping-pong ball cover on main bath exhaust. |
| 1440 | Increase V6 → 13.3% to restart flow. G1 falls by ~1 mbar as G2 rises. |
| 1510 | Increase V6 → 13.4% to restart flow. G1 falls by ~6 mbar as G2 rises. |
| 1535 | Stop cleaning through Trap 1 after 65 min. G2 flow pressure was 575-695 mbar. Pump mixture to dump. Removed 4.6 mbar. |
| 1555 | LN2 Trap 2 is mostly warm. Check contents: 3.6-1.2 = 2.4 mbar on G1. Pump out with scroll pump. |
| 1610 | MC(Cernox) = 82.8 K, Sorb = 127.4 K, IVC = 1.4 mbar, Level resistor = 1.261 kΩ. DIB4 pD SQUID = 1.505 kΩ. |
| 1705 | LN2 Trap 1 is mostly warm. Check contents: 5.0-0.4 = 4.6 mbar on G1. Pump out with scroll pump. |
| 1735 | Set up passive cleaning with both sides of dump and pump contents exposed to Trap 1 and Trap 2. With 3He pump on, open V9, V4, V12A+speedi, V12B+speedi, V13A, V13B. |