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2011/03/30

Temperature in the past a few hours
0753 Stop the run at 07110329_2325_F0162. At about 06:14 in the morning. A temperature glitch happened and then temperature drops. Tower temperature 43.1mK.
0758 Start to flash detector.
0942 Tower temperature went up to 1.4K. Stop flashing.
0959 G1=766mbar, G2==696mbar. The mixing process must stopped. Need to recondensing again. I think the fridge entered one shot mode after the temperature glitch. There might be a blockage in the circulation line.
1002 Closing V6. P1=0.032mbar.
1005 V6 is closed. P1=0.7mbar. G1=766mbar, G2=696mbar
1006 Open v3 to let mixture condense from both ends of fridge. G1=126mbar. G2=378mbar. V12A=100%.
1008 G2 and G1 keep dropping. Tower T=1.77K.
1016 G1=57mbar, G2=51mbar and both plateaued. The condensing is done. Now close V3 and open V6 to 20% to start circulation.
G1 and G2 shoot above 600mbar. Close V6 to 13%.
1021 G1 = 667mbar and G2=604mbar. G1 and G2 don't change when V3 is closed. It looks like there is a blockage in the condenser line. It is probably the He cold trap.
1105 Filled N2 cold trap.
1106 Closed condenser speedivalve.
1107 Close V13A, open V9, V5 to pump the N2 and He cold traps. Close V6 all the way.
1449 Open V14 to let the mixture expand if to the dump if they would. G1=2.5mbar and almost plateaued.
1654 G1=2.3mbar. G2=30mbar, P1=75mbar. Close V12A.
1751 G1 = 1.0mabr, G2=31.3mbar, P1=1000mbar. Can not pump G1 lower. Close V1, G1 stays about the same. Open V2 to pump mixture out of the lines.
1811 G1=0.8mbar. Close V2. G1 fluctuates around 1mbar.
1812 Close V5, G1 increases to 4mbar. Open V5, G1 drops to 1mbar. Open V5, V1, pump G1 to 1mbar and then close V5, G1 rise to 2.3mbar.
1822 Pull out the He cold trap and G1 went up to 50 mbar.
1823 Switch He4 pump to exhaust. Close V4A, Open V5A, V2A V7, V2 to pump the He cold trap.
1840 Heat the He trap to above 100C and continue pumping. Pull out N2 cold trap 1, G1 increases. Open V12A. Heat N2 cold trap 1.
1909 There might a leak from the N2 cold trap 1 safety valve. Tighten it.
1942 G1 = 1.3mbar and is nearly plateau. Close V2, V7, V2A, V4A. Open V4A to start 1K pot. Switch He4 pump to He recovery.
1945 Put N2 cold trap 1 into liquid N2 dewar.
2009 Insert He cold trap into the bath. Open condenser speedivalve, start circulate mixture. The blockage seems to be removed.
2032 Begun Helium transfer.
2033 Close V14 at P1=1.3mbar. G1=82.5mbar, G2=94.7mbar.
2114 Finished Helium Transfer
2125 Tower T=60mK. The fridge is back to business. Start flashing the detector.
2323 Stop flashing detector.