sPHENIX discussion of the superconducting solenoid

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

Hi,

 

1008B mezzanine is pretty busy.

 

Soon after noon, the sPHENIX Power Supply has been running at top current ~4800-ish A (operating +5% … though we won’t do this again for the Magnet as we did in 2018).

You can read the current from power supply and somehow it’s in an open-loop mode (not our standard operating condition) and the current value is drifting.

The current scaling factors are found to be wrong so that the pet/gpm pages or quench detectors all got incorrect currents (and trigger quenches).  Carl and Pablo are working

to reconcile.  I attach a plot which you see currents (in incorrect scale) going up in steps 😊  

 

The current goes through the power supply, dump resistor and the water-cooled-buses.  The temperature of the water (return) is about 25 C.

 

We’re going to run the power supply at this current for 24 hours just to make sure that nothing will go wrong.   Pablo wants to use tomorrow (after the 24 hour clock)

to finish the test.   So, if all goes well, the plan now is to disconnect the copper-bar (for short-circuit) and reconnect the braids on Thursday and go to the next step …

 

Pablo has written the LOTO procedures to turn on and turn off the power supply.   Mike Dany and Suresh Deonarine came to 1008B mezzanine and met with us.  They have got

some comments.   After some discussion, it’s agreed that Pablo will pass his information to Mike and Mike will incorporate Pablo’s LOTO procedure in the formal document (to

make it look better 😊).

 

 

Kin

 

From: Yip <kinyip AT bnl.gov>
Sent: Tuesday, October 18, 2022 3:04 PM
To: Yip, Kin <kinyip AT bnl.gov>
Subject: test

 

 

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