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2013/03/08

0010 IVC has been pumped out for around three hours, which really isn't enough. It would be best to wait until morning before performing a leak check. Additionally, pumping on the mixing chamber lines in the fridge overnight would be prudent: the traps can always be cleaned tomorrow while conducting a quick electrical check.
Fill N2 cold trap full in an effort to minimise contamination entering dump.
0025 Went around IVC 4 times tightening bottom flange.
0035 Hook up helium dewar to recovery line.
1015 Filled LN2 cold trap full.
1030 Fed Cricket 4 pellets.
1210 Mixture in dump (G2=715.6 mbar), began cleaning cold traps.
1250 Performed leak check. Background rate: 1.2E-9mbar l/s. Leak rate: 1.46E-9 -1.59E-9 mbar l/s. No leak found.
1300 Isolate leak checker and resume evacuating IVC with turbo pump.
Pull helium cold trap out of port and pump on it with He-4 pump. Continue to pump on nitrogen cold traps.
1315 Commence cleaning of cold traps.
1340 Quick electrical check yields little difference between today's values and those taken yesterday.
1700 Stop evacuating traps. Place helium cold trap back in position. Place nitrogen cold traps back in their bath. Start cryocleaning mixture through nitrogen cold trap 2.
Raise dewar and evacuate main bath.
1715 Open valve to leak checker and isolate turbo pump. Background helium leak rate in IVC 1.4E-9 mbar l/s. Fill IVC with helium gas, leak rate gradually increases to 1.8E-9 mbar l/s: no gross leak.
1725 Evacuate 1 K pot.
Fill IVC with 46 mbar of nitrogen exchange gas.
1730 Start nitrogen transfer.
1841 Fed Cricket 4 pellets.
2005 Nitrogen liquid level meter resistance 1.32 kΩ. Nitrogen transfer complete. Attach ping-pong ball.
2300 Fill N2 cold trap full.