UMN CDMS Wiki archive
start › cdms › k100 › run_diary › 20180517

2018/05/17 (Thursday)

Previous Day

Status: 1K Pot is not working. Warming up to examine it.
0540 MC(Cernox) = 116.9 K
0710 MC(Cernox) = 125.1 K
0740 MC(Cernox) = 127.8 K
slow warming curve. Maybe the still and MC heaters help, didn't use them this time.
0905 MC(Cernox)/1K Pot/Sorb = 135.1/>7/>250 K. Pot and Sorb rising steadily.
0905 Turn on MC and Still heaters to 20 mW each
0905 Cryostat vacuum jacket = 100 μbar
0910 Let two hose-lengths He gas into cryostat vacuum jacket. Vacuum jacket → 1.2 mbar
0910 Set up heat gun to blow up at bottom of main bath
0915 Make sure 1K Pot needle valve is fully closed, then check pressure in 1K Pot: 50 mbar on P2, 1.5/30 bar on mechanical gauge. Pump out with scroll pump.
0920 Stop pumping on 1K Pot, leave speedivalve open to watch pressure on P2:
minutes mbar (P2)
0 0.08
0.5 0.45
1.0 1.3
1.5 2.4
2.0 3.4
3.0 4.5
4.0 5.5
5.0 7.0
0925 Pump out 1K Pot again with scroll pump, down to 0.080 mbar.
Open needle valve a few degrees, → 0.090 mbar.
Open needle valve a few more degrees, → 0.110 mbar.
Open needle valve to about 90 degrees, → 0.260 mbar
Open needle valve to about 180 degrees, → 4.5 mbar
0930 With needle valve open 180 degrees, stop pumping on 1K Pot, leave speedivalve open to watch pressure on P2: rises off-scale in 20 seconds. After a few minutes reaches 13/30 bar on mechanical gauge, continues to rise.
0950 Pump out 1K Pot again with scroll pump, down to 0.080 mbar.
Open needle valve 10 degrees, → 0.110 mbar.
0950 With needle valve open 10 degrees, stop pumping on 1K Pot, leave speedivalve open to watch pressure on P2:
minutes mbar (P2)
0 0.11
0.5 0.9
1.0 2.8
1.5 4.5
2.0 5.5
3.0 9.5
0958 MC(Cernox) = 141.9 K
1200 MC(Cernox) = 168.3 K
1355 MC(Cernox) = 190.6 K
1625 MC(Cernox) = 215.3 K
1710 MC(Cernox) = 221.4 K
1910 MC(Cernox) = 236.1 K

Next Day