[Esr-users] [New Logentry] Hall B Solenoid Cryogenic Tuning

[kashy at jlab.org]

Logentry Text:
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This morning I continued to tune the Hall B Solenoid cryogenics. We were using the electric heater in the Lead Reservoir to increase the flow to stabilize the solenoid and also temperatures in the DBX. My goal was to find a control philosophy that we can run without wasting the cryogenic capacity. I decided to let the reservoir overflow and use the return temperature TD8522SR in the DBX as a control parameter. This temperature now is the input variable on the PID of EV8611JT_Min with a set value of 7.3K (calibration accuracy is in question as the lowest I've seen this is 6.8K). Now the heater is off and we are letting the enthalpy of the liquid boiling cool the return u-tube. I lowered the control point for the VCL flow from 60 to 40 slm (each lead) and these are staying nicely cool (5.9K). I also lowered the back pressure valve setpoint to 1.35atm on the Lead reservoir. 

The system is stable. 
These settings should be good for powering the magnet too.


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