stm:warming_up_procedure
Differences
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| stm:warming_up_procedure [2007/04/05 13:26] – created galli | stm:warming_up_procedure [2007/04/05 13:28] (current) – galli | ||
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| + | ====== Warming up the entire cryostat to room temperature ====== | ||
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| + | That's rather simple: just stop filling the helium tank and the nitrogen tank. The system will warm up by itself in about 3 days. You can follow the warming up by checking the two thermometers (VTI-bottom and λ-plate, T1 and T2). 7Ω is nitrogen temperature, | ||
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| + | In any case there are some //very important// measures to be taken while warming up, to avoid explosions of tubes or capillaries due to the expansion of gases (Helium, Nitrogen and air) when warming up from low T to room T. //Never forget these steps before warming up//, or cryostat damage can be a consequence. | ||
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| + | - Close the needle valves. | ||
| + | - Connect He-tank to recovery (should be already like that). | ||
| + | - Connect VTI to recovery. | ||
| + | - Conenct λ-plate pumping line to recovery. | ||
| + | - Put an overpressure release after the speedy valve of the vacuum interspace. When the cryostat is still a bit cold (~19Ω or less), open the speedy valve. The underpressure will keep the space sealed automatically, | ||
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| + | Warnings and advises: | ||
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| + | - NEVER NEVER NEVER vent the superinsulation, | ||
| + | - If you do not want to keep the cryostat warm for long, it's convenient to keep a Helium vessel connected to the recovery close to the cryostat, so that the boiloff will keep the cryostat " | ||
| + | - If you want to keep the cryostat warm for a long time, avoid to vent any space to air. | ||