2019/05/23 (Thursday)
| Status: | 1K pot clogged at 4K, warming back up. Helium exchange gas in cryostat jacket and IVC. |
|---|---|
| 0900 | MC(Cernox) = 280.7 K, Vacuum jacket = 1.2 mbar Start pumping out vacuum jacket with scroll pump. |
| 0905 | LN2 Trap 1 is room temp. Check contents: 4.8-1.4 = 3.4 mbar on G1. Pump out with 4He pump from both sides of the trap by opening both V2 and V11A. |
| 0912 | Start pumping vacuum jacket with turbo pump. |
| 0920 | Turbo on cryostat vacuum jacket = 220 nbar |
| 0922 | Put cold trap 1 in LN2 bath and top off LN2 bath. |
| 0930 | Turn off Still and MC heaters. |
| 0935 | Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.4% |
| 0938 | Turbo on cryostat vacuum jacket = 74 nbar |
| 0945 | Increase V6→13.0% to restart flow |
| 0952 | Increase V6→13.1% to restart flow |
| 0955 | Turbo on cryostat vacuum jacket = 46 nbar |
| 1100 | Stop cleaning through Trap 1 after 85 min. G2 flow pressure was 570-590 mbar. Pump mixture to dump. Removed 5.7 mbar |
| 1105 | Turbo on cryostat vacuum jacket = 30 nbar. |
| 1122 | Take cold trap 1 out to warm up. |
| 1200 | Turbo on cryostat vacuum jacket = 25 nbar. With pump valved out, cryostat vacuum jacket = 250 nbar. Stop pumping on cryostat vacuum jacket valve. |
| 1205 | IVC = 12 mbar on digital gauge. Begin pumping out IVC with scroll pump. |
| 1215 | Switch over to pumping on IVC with turbo. |
| 1235 | LN2 Trap 1 is room temp. Check contents: 6.5-0.8 = 5.7 mbar on G1. Pump out with 4He pump from both sides of the trap by opening both V2 and V11A. |
| 1252 | Put cold trap 1 back in LN2 bath. |
| 1253 | Turbo on IVC = 30 nbar |
| 1258 | Check pressure in condenser line (includes LHe cold trap) at G1 by opening V1. 2.0-1.6 = 0.4 mbar. Check pressure in fridge at condenser side on G1 by opening condenser valve. 2.1-2.0=0.1 mbar. Check pressure in fridge at still side on P1 by opening still gate valve: P1=0.16 mbar. Pump out both sides of fridge with scroll pump. |
| 1320 | G1/P1 = 0.9/0.2 mbar. P1 is still decreasing slowly. |
| 1400 | G1/P1 = 0.9/0.11 mbar. Stop pumping out fridge lines. |
| 1404 | Open dump to both sides of fridge lines via LN2 cold trap 1. |
| 1405 | 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. |
| 1415 | P2 < 1 mbar, close V4A. Open V5A, V2A, and the vent speedivalve to evacuate the clear hose leading to the He gas line. Close off scroll pump. Flush MB and 1K pot (both speedivalve and needle valve open) with 320 mbar (above 1 atm) of 4He gas. Close the 1K Pot speedivalve and needle valve. |
| 1420 | For the 2nd time, 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. |
| 1430 | P2 < 1 mbar, close off scroll pump. Pressurize MB and 1K pot (both speedivalve and needle valve open) with 280 mbar (above 1 atm) of 4He gas. Close 1K Pot needle valve and speedivalve. |
| 1433 | Turbo on IVC = 16 nbar. IVC = 120 nbar with pump valved out. |
| 1440 | Let 5.4 mbar He exchange gas into IVC |
| 1445 | Begin LN2 transfer. |
| 1450 | MC(Cernox) = 282.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 616 mbar, Level resistor = 0.996 kΩ |
| 1452 | Like we did on 2019/05/18 , let's flow mix through the fridge as we cool. Open V6→12.4%. Then close V3. Now we have the circulation pump pulling at the Still side, it's output is open to the dump via V9 and cold trap 1. Cold trap 1 is open to the condenser side. |
| 1458 | G1/G2 = 616/557 mbar and flat. |
| 1500 | MC(Cernox) = 281.8 K, Sorb = >249 K (max), IVC = 5.4 mbar, G1 (fridge) = 615 mbar, Level resistor = 1.063 kΩ. DIB4 pD SQUID = 3.2 kΩ. |
| 1503 | Start some flow by closing V13A and opening V6 a few clicks to V6→13.1%, where G2 starts to rise a little bit. Reopen V13A. |
| 1509 | G1/G2 = 730/663 mbar and flat. |
| 1510 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 15.5 mbar/min and G2 remains flat. |
| 1515 | MC(Cernox) = 270.6 K, Sorb = >249 K (max), IVC = 4.6 mbar, G1 (fridge) = 730 mbar, Level resistor = 1.143 kΩ. DIB4 pD SQUID = 3.1 kΩ. |
| 1525 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 18.3 mbar/min |
| 1530 | MC(Cernox) = 248.7 K, Sorb = >249 K (max), IVC = 4.6 mbar, G1 (fridge) = 728 mbar, Level resistor = 1.221 kΩ. DIB4 pD SQUID = 2.7 kΩ. |
| 1540 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 19.9 mbar/min |
| 1545 | MC(Cernox) = 221.1 K, Sorb = >249 K (max), IVC = 3.0 mbar, G1 (fridge) = 727 mbar, Level resistor = 1.302 kΩ. DIB4 pD SQUID = 2.3 kΩ but unstable. The level resistor doesn't usually read this high so early on in the transfer. Playing with the wiring doesn't seem to change things. |
| 1550 | Take out level resistor and dip in in the LN2 cold trap bath, it reads 1.343 kΩ. Put level resistor back in main bath port. |
| 1555 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 25.5 mbar/min |
| 1600 | MC(Cernox) = 195.6 K, Sorb = >249 K (max), IVC = 2.5 mbar, G1 (fridge) = 725 mbar, Level resistor = 1.322 kΩ. DIB4 pD SQUID = 2.0 kΩ |
| 1610 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 31.9 mbar/min |
| 1615 | MC(Cernox) = 175.0 K, Sorb = 209.6 K, IVC = 2.2 mbar, G1 (fridge) = 723 mbar, Level resistor = 1.335 kΩ. DIB4 pD SQUID = unstable |
| 1625 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 36.5 mbar/min |
| 1630 | MC(Cernox) = 160.7 K, Sorb = 179.8 K, IVC = 2.2 mbar, G1 (fridge) = 720 mbar, Level resistor = 1.341 kΩ. DIB4 pD SQUID = unstable |
| 1640 | Close V12A speedivalve for a minute, then re-open it. G1 decreases at 41.9 mbar/min |
| 1645 | MC(Cernox) = 148.6 K, Sorb = 158.2 K, IVC = 2.2 mbar, G1 (fridge) = 717 mbar, Level resistor = 1.343 kΩ. DIB4 pD SQUID = 1.7 kΩ |
| 1646 | Cease LN2 transfer and put ping pong ball on main bath port |
| 1650 | Close V6 and open V3 to leave the dump open to both sides of the fridge via cold trap 1. |
| 1700 | MC(Cernox) = 137.7 K, Sorb = 143.3 K, IVC = 2.2 mbar, G1 (fridge) = 607 mbar, DIB4 pD SQUID = unstable |
| 1730 | MC(Cernox) = 122.1 K, Sorb = 130.4 K, IVC = 2.2 mbar, G1 (fridge) = 608 mbar, DIB4 pD SQUID = unstable |
| 1910 | MC(Cernox) = 93.6 K, Sorb = 122.9 K, IVC = 1.6 mbar, G1 (fridge) = 610 mbar, DIB4 pD SQUID = unstable |
| 2100 | MC(Cernox) = 81.9 K, Sorb = 122.9 K, IVC = 1.6 mbar, G1 (fridge) = 612 mbar, DIB4 pD SQUID = unstable |