sPHENIX discussion of the superconducting solenoid

["Yip, Kin" <kinyip AT bnl.gov>]

Hello,

 

Why am I at the Lab. Friday after 6:30 pm ?

 

Well, partly because I have nothing else to do and partly maybe I have a hunch for what was going to happen …

 

At about 18:37, there was a power dip which brought down our beloved sPHENIX Magnet (fast discharge) and RHIC yellow/blue beams,

as well as STAR magnet, AGS MMPS, Booster, AGS, Linac RF ….

 

So, I came up to 1008B mezzanine and took a picture of the power supply PLC interlock history (nothing inspiring) and the quench detector/Labview program.

On the quench detector/Labview, it’s the classical “coil difference” that caused the quench interlock.  

 

I’ve restarted the Labview program and reset everything that I can reset in the PLC and pet.  Writing to here, I actually just remember to

reset the currents to 0 in the ramp page.  Otherwise, it’ll complain when we try to ramp 😊   As experienced I’m now 😅

 

Before we can attempt to ramp the magnet back, we need to Cryo to clear the Cryo interlock and Cryo permissive which would take a few hours.   When

that’s ready, I’ll ask CAS to press the contactor at the dump resistor.   I talked to the CAS staff today who knows which button to press.

 

 

Carl and Pablo, I’ve attached the pictures of the PLC interlock history as well as the Labview display before I restarted the quench program.

I also attached the plot of magnet currents at the time of fast-discharge.   You may investigate more … Let me know if there is something
more than power dip causing the fast-discharge. 

 

 

Kin

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