sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Agenda, John Cozzolino's and Ed O'Brien's presentation powerpoints can be found :  https://indico.bnl.gov/conferenceDisplay.py?confId=2295


Brief Summary :

1.  John Cozzolino gave a presentation of his 2D ANSYS Maxwell analysis of the sPHENIX coil mainly in the full-field test configuration (boxes/plates
as return yoke).  

Compared to what he did last year using Wuzheng's pressure in each coil segment as input to ANSYS, this time he only uses Wuzheng's current densities
of the 24 segments of the coils at full current 4596 A (--- though John said 4600 A in his powerpoint, Wuzheng's current densities were really 4596 A to
be exact --- just very trivially mentioning here :-)     as input to ANSYS Maxwell which calculates the magnetic fields/forces/pressure and can be/has been
easily exported to the mechanical model for stress analysis.

John compares his new results with last year's results.   They generally agree pretty well though the new results often give lower maximum stresses
in various spots and various stress analyses ( tensile, shear, reflection etc.).    The tensile, shear and axial compressive stresses all seem to be below
30 MPa.

(     John's presentation can also been found  :
https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Past%20Presentations/2016-8-3%20sPHENIX%20FE%202D%20Analysis%20on%20the%20Coil%20mainly.pptx

in addition to the above-mentioned indico page.    )


2.  At the end, there was a discussion whether he should go on to pursue a 3D analysis, this time mainly for the stress outside the cryostat, the return yoke
wall and the support structures.   The answer seemed to be "yes" and John will need more information in the Creo system from Jon Hock to really do his analysis.

2.1  D. Phillips told me that Jon Hock may return on Aug. 17/18 .


3.   Ed O'Brien showed a one-page summary of  "cost to complete high-field test" (which can be found in the above-mentioned indico page).

His accounts are running out of money for us to purchase.   Until he can find more money, we may not be able to purchase anything before Oct. 1.
At the moment, the Cryo group's "burst disk" PO is on-hold .......

3.1 In the meeting, we clarified that the front-end-electronics ($15K) and quench-detector data acquisition boards ($35K) are the same for the high-field test and
the final sPHENIX installation in 1008.   Here, we've already used the ERL quench-detectors and trying to ask Piyush to let us use his old quench detectors wouldn't
save us money.


3.2   During the meeting, I have agreed to ask Pablo whether we may save his $8000.  I have asked after the meeting and to the first order, the answer is "no" ...
as they mainly want to replace those very old (20 years ?!)  capacitors as the power-supply review members (July 22, 2016) have wanted.    I wonder how
much we really want to save here ...

3.2.1  By talking with Pablo, I got the news that they have done half of the work to try to test the power supply to ~3000 A.   Pablo has found a magnet load for this.
D. Phillips later told me that they're not sure whether the cooling water could let them go to 3000 A but they'll try as much as possible.     Everything is "FREE" here !


3.3   Then, the next saving possibilities are related to those for making the return yoke.

3.3.1  Ed is asking Dave Phillips to send the Physics Dept. a list of all the bolts that we want to buy for the high-field test and Ed would find a dedicated person who is
very familiar with bolt purchasing to find the cheapest deal.     Dave told me that he doesn't have a complete list yet and may need to consult with J. Hock.  He gladly
shed off this task.

3.3.2  Ed doesn't want to continue to pay additional for "Central Shop welding support".

3.3.3  Ed would like to discuss with J. Hock to see whether we may reduce the amount of $70K for "Aluminum Coil Jack Stands" after Jon comes back from vacation
(Aug. 17/18).

3.3.4  Ed is asking whether we really need to pay $2.5K for "hand rails".   D. Phillips told me that it's cheaper to buy new ones than trying to make the old ones work.


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Very subjective observation here :  it's now a battle between (or discussion of) how strong a desire to save money and how strong a desire to get things done in certain
optimal ways.  C'est la vie !

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4.  Peter Wanderer told me that he's asked Brett Parker to check the eddy current situation during a quench for our sPHENIX magnet.  If the eddy current falls off more or
less (not a factor of 10) the same way as the coil current, there wouldn't be any problem during a quench.

Joe Muratore reported that he's still working on the "Low Field Test Note".