[Hallb-engineering] [Revised Logentry] Follow-up Re: Hall B Cooldown to 4K

[kashy at jlab.org]

Logentry Text:
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We started flowing to the Hall at 2g/s at 10:20 first to the Torus and then the Solenoid. We had a significant oscillation that we also had on previous cooldowns. It effected nearly every signal. This time we documented in our procedure and also here. The oscillation was stopped when we throttled PV8522TR to 10%. We believe that flow into and out of the 4K return line was heating the supply flow and causing the oscillation.

See plots

Now we are cooling the Toru at 2.8K/hr and the solenoid at 2.2K/hr.
The Torus is at 73K and Solenoid is at 49K

The Buffer Dewar is not flowing yet and still has 21% helium level.


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