2019/05/03 (Friday)

Previous Day

Status	Warming up after a second blockage. Nitrogen in IVC and cryostat vacuum jacket.
Setup	DIB1/3/4 → 3.2 MHz filters 2/3/1 → cable 3/1/2
0925	LN2 Trap 2 is warm. Check contents: 5.0-1.7 = 3.3 mbar on G1. Pump out with 4He pump.
0925	MC(Cernox) = 282.1 K warming time constant around 14.1 hours, should hit 10 celsius at 10:40.
0945	Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 12.6%
0950	Increase V6 → 12.8% to restart flow
1000	Increase V6 → 12.9% to speed up flow
1035	Increase V6 → 13.0% to speed up flow
1050	Stop cleaning through Trap 1 after 65 min. G2 flow pressure was 575-700 mbar. Pump mixture to dump. Removed 3.0 mbar.
1150	Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 12.8%
1155	Increase V6 → 12.9% to restart flow
1205	Increase V6 → 13.0% to restart flow
1225	Increase V6 → 13.1% to speed up flow
1310	Stop cleaning through Trap 2 after 80 min. G2 flow pressure was 570-655 mbar. Pump mixture to dump. Removed 4.3 mbar.
1330	LN2 Trap 1 is warm. Check contents: 4.7-1.7 = 3.0 mbar on G1. Pump out with 4He pump.
1345	Start cryocleaning mixture through LN2 Cold Trap 1, V6 = 13.0%
1345	MC(Cernox) = 285.7 K. Cryostat vacuum jacket = 12 mbar. Start pumping it out with scroll pump. After about 20 minutes, pressure falls below 50 μbar, so switch to turbo pump.
1355	Increase V6 → 13.1% to restart flow
1410	Increase V6 → 13.2% to speed up flow
1450	Stop cleaning through Trap 1 after 60 min. G2 flow pressure was 625-700 mbar. Pump mixture to dump. Removed 5.8 mbar.
1505	LN2 Trap 2 is warm. Check contents: 5.7-1.4 = 4.3 mbar on G1. Pump out with 4He pump.
1520	Start cryocleaning mixture through LN2 Cold Trap 2, V6 = 13.2%
1535	Increase V6 → 13.3% to speed up flow
1550	Increase V6 → 13.4% to speed up flow
1630	Stop cleaning through Trap 2 after 70 min. G2 flow pressure was 570-610 mbar. Pump mixture to dump. Removed 4.7 mbar.
1635	Turbo on cryostat vacuum jacket = 19 nbar. Jacket = 250 nbar with pump valved out a few minutes. Good enough, stop pumping on cryostat vacuum jacket.
1645	IVC = 190 mbar on digital gauge, 0.4 bar on mechanical gauge. Start pumping it out gently with scroll pump.
1645	LN2 Trap 1 is warm. Check contents: 7.5-1.7 = 5.8 mbar on G1. Pump out with 4He pump.
1650	Start pumping IVC with turbo pump
1715	LN2 Trap 2 is mostly warm. Check contents: 6.3-1.6 = 4.7 mbar on G1. Pump out with 4He pump.

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