sPHENIX discussion of the superconducting solenoid

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

Hi,

 

As you may see from the email below, the Cryo group found a plug and they needed to flow with warm gas for a bit.

The outlet temperature was < 155 K at the lowest but now it’s artificially high since 11:30 am.  The magnet coil temperatures

may have risen 1 K or something since ~11:30 am.  

 

They didn’t quite understand and think it may be “H2O”.  Then the “H2O” would just move from one place to another.  It may

happen again, but just in a different place  or  it may never happen again J  

 

Roberto told me that they’ll start cooling again at 6 pm.

 

Two linear pots (pot. 1 and 3) have read 0 and the other two read ~0.02 and ~0.01 which would soon go to 0 if the system cools further.

I’ve also made a plot of the strain gauges for 4 random channels.   Both of these pot & strain gauges show a little rise at the end, due

to the non-cooling situation.

 

Kin

 

From: Than, Yatming (Roberto)
Sent: Monday, March 07, 2016 2:04 PM
To: Yip, Kin
Subject: RE: [Sphenix-magnet-l] daily report : ~164 K ... Slightly faster (Cryo Group has switched to use the Plant ? )

 

 

Kin,

We stopped the cooling loop for a few hours.

It seemed a plugged developed on the return line from the phase separator to our system.

Still scratching my head how it could have happen.

This happen sometime, after midnight.

 

Looks like the plug cleared, but we will flow warm gas for a few hours then restart cooling loop.

 

Roberto

 

 

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