2013/10/19
Helium cold trap taken out of circulation and manifold constructed with two NW-25 1 m long bellows and two NW-16 & NW-25 adapters. Manifold and nitrogen cold trap 1 left to evacuate overnight.
| 1650 | Pressures in P1, G1 & G2 are higher than they were last night. Temperature in laboratory is higher though, so this may explain it. Bellows on manifold do not appear to be under high vacuum, but this could be misleading. Unfortunately, unable to pump on them with turbo pump, so have to hope roughing pumps are good enough. Stop pumping on manifold with 1 K pot pump, and use He-3 circulation pump. Dump is not open, but little air is in line (G1 is at 2 mbar) so unlikely to cause any problems. |
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| 1950 | Close all valves on IGH. Insert nitrogen cold trap 1 into liquid nitrogen reservoir and fill N2 cold trap full. Allow mixture into nitrogen cold trap 1 through valve V13A and leave it to cool. Open condenser line speedivalve and gate valve. Open manual valves on dump to allow mixture to flow into nitrogen cold trap. Assume that 685 mbar of mixture is in dump. Start 1 K pot, temperature 1.8 K. |
| Commence manual condensation procedure through nitrogen cold trap 1. | |
| 2105 | Valve V12A on IGH fully open: manual condensation procedure complete. Left 335 mbar of mixture in dump (approximately 350 mbar of mixture in fridge). Mixing chamber temperature 5.8 K and falling. |
| 2205 | Mixing chamber temperature 2.3 K. Commence manual circulation procedure. |
| 2230 | Valve V6 on IGH fully open: manual circulation procedure complete. Wait for mixing chamber to reach base temperature. |