sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

1. Yesterday, I sent an email to A. Jain (in SMD) to ask him for help to evaluate our Magnet System in a quench situation and I included a lot of
analyses done by the BaBar expt. and the companies they've hired.   Peter Wanderer told me that A. Jain wouldn't have time to do this before he
leaves BNL.  Peter will try to find somebody to help looking into this "quench situation".

My thought is: since BaBar etc. have done quite substantial analyses and our inductance (with our return yoke) is lower than that of BaBar which
implies lower eddy current (when there is eddy current) => so if it's not a problem of the BaBar expt., then it's a problem for us.


2. Dave Phillips reported that Jon Hock has made good progress in his ANSYS model and stress analysis.  So far, applying Wuzheng's total force (from Opera)
uniformly on the steel wall surface, there doesn't seem to be any stress issue.   We may need to do more conservative calculation to evaluate this (with help
from John Cozzolino etc.).

A couple guys are still drilling the holes every day and this may continue for months.   Though Dave hasn't quite finished the scheduling, preliminarily the
schedule indicates that by Jan. 1, 2017, the construction for the return yoke may be complete such that the Cryo group has started to work on the Cryo system.
This is still an "idealistic" as it assumes that the two guys drilling holes will do it every day and all the necessary labor forces will be available when we
need it.   And Jan. 1, 2017 is also close to the RHIC start-up time and people may be busy.

3.  Paul Orfin showed us the cost comparison between tapping into RHIC cryo plant   and   using the existing ERL 1660 plant.  I've put Paul Orfin's transparencies:

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Past%20Presentations/2016-6-8_RHIC%20vs%20ERL%20Plant%20comparison.pptx

If available (which is a question),  the ERL 1660 plant seems cheaper on paper but it hasn't included the cost for building the platform and there are a lot of operating issues and it's of "high maintenance type".    One can't really put the plant outside the shield wall as it'll be too long and it'd lose all the cryo flow. 
And if the 1660 plant is inside the shield wall, then when there is problem, the Cryo will need to make access into the expt. hall to fix it.   And unlike the RHIC system, there is backup !  Any backup would cost additional problem.   In general, people don't quite like the ERL 1660 plant.  If we want to save money, it seems to make more sense to drop one or two options from Paul's presentation.


4.  A few miscellaneous items:

--- Yesterday, J. Mills, D. Phillips, M. Anerella, J. Cozzolino, J. Hock and myself had a meeting.  John Cozzolino is trying to use the Magnetic ANSYS to find magnetic field/force from scratch and then pass the forces to Jon,  and/or do the stress analysis.

--- Today, I got some complicated instructions from Wuzheng Meng to show force distributions on the surfaces of the steel wall.  I may try to see whether I could do it.

--- There will be a small meeting tomorrow at LCR (1:30 pm) that a few of us will gather to discuss the strain gauge DAQ system.