sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

1.  Both Roberto (working in CeC)  and Paul Orfin (working in sPHENIX Magnet Cryo) couldn't show up.  I called Paul a few minutes before 1:30 pm  at x4833 (a telephone next to the sPHENIX Magnet) and he told me that the plug was still there even after yesterday's evacuation.   He's working to try to get the presumably H2O as thoroughly as he could so that the plug wouldn't reappear.  He would know whether the problem is solved or not only by cooling down again to see whether the plug reappears or not.  

    The temperature of the magnet coil is ~150 K or so.   The cool-down can continue only when they solve this "plug" problem.

2.  We then discussed about the quench analysis.   It's a bit of messy discussion (in my opinion, as probably I don't understand too many things) as people raised different issues.   I tried to pretend to be logical here ...

     I showed what I said before in email:  in our BaBar server (\\bnl.gov\c-adnas\babar), under the directory of "Volume 5 DESIGN AND QUALITY CONTROL REPORT",  there is the file  "Quench Protect Review.pdf", esp. p. 19-54, which is the quench analysis.   There is a thought that BaBar/Ansaldo has done it and maybe we can use it as it's.  Probably we just need an expert to say that this is enough. ( Editorial comment: It's enough for me. )

   Dave Phillips raised his favorite question whether we should keep the natural ~3 cm (or 28.5 mm) offset
like what BaBar has done.  In static situation, the force is 8 ~ Metric tonnes.  He's asking whether somebody
can do some calculations to show whether the force would change signs (and how much) during a quench.
( Editorial comment: I'd just leave it as what BaBar has done. )

   Peter Wanderer said that he'd try to ask Ramesh Gupta (?) to see whether he can help.

   In any case, it's said that we'll put our calculations together (including all the stress analyses that we have done) and show them to the Magnet Oversight Committee to have their opinions.


2.1   I drew people's attention to the above-mentioned quench document, they found that the "aluminium strips" would reduce heating and thus stress
    during a quench.  This is what Ansaldo has done.  Pasquale told that was what they did and he had a photo showing them :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Shared%20Documents/Documents%20introduced%20or%20sent%20to%20us%20by%20Pasquale%20Fabbricatore/Aluminium%20strips%20to%20reduce%20stress%20during%20quench.jpg


3.  D. Phillips asked about the RRR and Piyush Joshi and Joe Muratore told us that they'll try to measure the resistance at 10 K (and then at room temperature).  After the meeting, Piyush/Joe told me that they'd like the warm-up to be slow up to 10 K so that they could measure the resistance with hopefully no temperature gradient throughout the magnet coil.