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2014/05/03

0030 Fill N2 cold trap not full: about a litre shy.
Tower temperature 76.5 mK: about 1 mK too high for data acquisition. This is probably due to high pressure of helium in main bath after transfer. Will leave overnight to see if it improves.
1530 Tower temperature has risen to 77.1 mK. Although there are no vibrations from main bath, attempted to help matters by venting helium gas for 2 minutes, thus releasing pressure. Tower temperature did fall a little to 76.9 mK. Will continue to monitor situation.
Fill N2 cold trap full. As expected, tower temperature has started to decrease. However, this is typical when filling the cold trap. Wait for an hour before deciding if a more drastic course of action is required.
1730 Tower temperature 76.8 mK. Switch to mixing chamber thermometer. Mixing chamber temperature 68.5 mK. Temperature gradient looks alright.
1735 Check that traces haven't railed, and thus heat load is not being applied to tower. Traces look fine. Re-establish timing link and switch back to tower thermometer. No change in temperature.
1750 Vented main bath for 10 minutes. Monitor tower temperature.
1920 Tower temperature appears to have stabilised at 75.6 mK, which is good enough. Looks like venting the main bath helped. Continue to monitor temperature.