sPHENIX discussion of the superconducting solenoid

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

Agenda/powerpoint slides (including those from Jon Hock and John Cozzolino): (https://indico.bnl.gov/conferenceDisplay.py?confId=2204)

 

 

1.      Jon Hock reported that he’s going forward with the bolted design for the return steel and adding brackets/straps to support the return steel. 
The central shop welder is preparing the return steel for assembly and technicians are tapping holes in the base to support the side/end walls.
Jon is doing further analysis by combining the information that he’s got from Wuzheng (the force values) and John (the main force coverage)
to do ANSYS analysis.

2.      John Cozzolino has sent me some very preliminary results from his new “ANSYS Maxwell 3D” analysis that he can find magnetic field and force

(and then do stress analysis all in ANSYS).   He’s made a comparison with Wuzheng’s results and for big forces, the difference in general are small
apart from a couple places.   And in private communication, the central field that he’s got is ~1.47 T, higher than Wuzheng’s 1.37 T (even though
both use the same current density) and John said that he’s taking a look to try to figure out the difference etc.

3.      Dave Phillips told us that there i no change in his schedule estimation (still Jan. 1, 2017 is the date to put up the Valve Box).   We have discussed how
to work on the scheduling during the meeting.  As a result, I’ve just distributed the Microsoft project file to various parties to ask them to update the
scheduling and then D. Phillips will combine them and add his own.

4.      I showed the email reply from Pablo Rosas.  They’re finishing the local control and will do “power testing” starting July.  Depending on what other
works in AGS etc. they’re asked to do, they may stop a bit before they can continue working on the sPHENIX power supply.   But he still expects
that the power supply will be available sometime in October.

5.      During the meeting, we discuss a bit about the “ticket” or questions left to us from previous review(s) about the situation in quenches.  I reported
the discussion that Holger Witte and I have had.  As far as forces during a quench are concerned, as force ~ JxB (and both J and B are falling during
a quench,  we’ll worry only if there are asymmetric structure (etc.) which creates eddy current and then force to pull the magnet.  Otherwise, the situation
shouldn’t be worse than in normal circumstances.  My argument was that we don’t really have significant asymmetry as it’s more or less cylindrically
symmetric and since our inductances (for both high-field test and sPHENIX) are lower than that of BaBar, any eddy current created must be lower than
that of BaBar.  And BaBar (or the companies which helped build the magnet) has done the quench analysis.   But people feel that we still need to ask Peter
Wanderer (who was absent from today’s meeting due to medical appointment) to help find people to look this over and make an educated statement.   

It happened that after the meeting, I ran into Peter Wanderer and mentioned the above quench discussion to him.  Peter has indicated to me (and J. Mills
who later happened to appear beside us) that he will look at this issue at the end of July.

6.      We heard from Mike Anerella that the cost estimate for the Cryo extension work (for the sPHENIX Magnet) should be completed by the end of this week.