2013/09/01
| 0455 | Managed to get background helium leak rate in mixing chamber lines down to 1.2E-6 mbar l/s. Conducted spray tests on flanges between condenser line speedivalve and IGH and nitrogen cold trap flanges: leak rate did not change. Evacuate lines for a little longer and repeat again in a few hours. |
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| Completed a couple of cycles of cold trap cleaning. Pressures in G1 and He-4 pump's exhaust rose, indicating contamination. Leave cold traps to pump out overnight. Shall repeat in morning. |