sPHENIX discussion of the superconducting solenoid

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

Hello,

I/we originally planned to ramp down the magnet at 6 am this morning.  Unfortunately, it tripped at 1:24 am this morning. 
After I drove to 1008B, I found that it's due to "Quench Watch Dog Timer" as shown in the HMI History picture (of the Magnet Supply).

{ Signature of this event: If it's due to other reasons, "Quench Watch Dog Timer" will be ~5 s late.  But since it's among the 1st one, it's the reason. }

I seemed to even have problem resetting the "Quench Watch Dog Timer" initially but it was reset half an hour later.

This is the 2nd occurrence of this problem and the first time was July 28.   Carl and CAS did some checks for the cables on July 31 but didn't really find anything but they tried to tighten the cable.

This afternoon, Carl Schultheiss and his colleague spent some time investigating Quench Watch Dog Timer.  They didn't find anything
obviously bad.  But

(1) they set up a permanent scope so that they can tell which side (Magnet PLC or Quench Rack) is at fault if it happens again;

(2) they changed the relay switch (as it was suggested last time ...).

I started ramping up the magnet at 16:27  after talking with MCR, 1008 and Cryo.  It was ramped back to top at 18:17 .

================

I have this fast-discharge/quench counter (so far there is never any real quench since 2023 operation):

https://docs.google.com/spreadsheets/d/1Uk1WOlLWPDLudvUJB0mV7EmkUOpjvpnpth05YMFrX-8/edit?gid=0#gid=0

The magnet was on since Sept. 13 until this morning (Oct. 10).  I counted that it remained at the top current for >634 hours --- the longest
so far ( almost 9 hours longer than last record) 😅

Kin

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