sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT fnal.gov>]

Hello,

 

I’ve just taken a screenshot of the Cryo HMI graphics.  Unfortunately, last Friday and Sat., we had two more ODH false alarms in Bldg. 912. 

Jonathan Reich told us that they know these are false alarms because the status flag said “HW” (hardware failure, never “ODH”.

 

You could see the coil temperature rises from my plot.   Jonathan’s group has replaced all 3 sensor units in Bldg. 912 and hopefully we

won’t see them fail again J    While Jonatha’s group was investigating and fixing ODH problem, the Cryo shut down the He Plant ~in the

weekend.  This morning, I saw Paul Orfin and Roberto in 912 restarting the Plant.  Right now, the liquid He dropped to 32.0/33.5% from

the Overview page.  They’re trying to get it to >70%.   So, they think that maybe by Wed., they can try to switch to it to cool down to 4 K.

 

Carl is working on this system, trying to solve his “offset” issue.  And he’ll use another short-circuit test to test John Morris’ new functions

and an interlock (with Pablo).  After Wed. or so when the Magnet is ~ cold, they can do the hipot  and  we can reconnect and Mike can install

the box.  [  In fact, Jim Mills is trying to get Mike to make some kinds of support to prevent too much force or torque on the Current Leads. ]

 

Carl said that we want the Magnet to soak in the cold environment for at least 24 hours and Mike’s time to install the box is the perfect time for such.

 

Kin

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