sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Agenda and powerpoints are : https://indico.bnl.gov/conferenceDisplay.py?confId=2419


1. I gave a presentation of my comparisons for the magnetic fields when we use ~1006 steel or ~1020 steel.  I used Wuzheng's sPHENIX model
   and ran Opera version 18 in fido of ITD.
 
   The BH curve for 1006 was "iron6a.bh" that Wuzheng has made.   The BH curve for the 1020 came from :
    http://www.fieldp.com/magneticproperties.html#Steel1020  (which actually has B &muR and I have had to do H=B/muR to get H). 
    Opera doesn't like the 1st non-zero point as its H is bigger than the 2nd one and so I took out that first non-zero point.

    The differences seem small.  At (0,0,0), Bz = 14001 G (~1006)  vs  13979 G (~1020).  The field distributions/shapes are more or less the
    same until you want to look for small B (eg. 5 G !) lines.   Somehow, there are more differences in the B field for low field around the x-axis
    (z being the beam axis/y being the vertical axis.).  So, the 5 G line would extend a bit further in the case of 1020 as more field lines leak outside
    the return yoke.

    The powerpoint file for this presentation can be found in the above indico link as well as here :
  https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Past%20Presentations/2016-9-28%20B%20field%20difference%20(1006%20vs%201020).pptx


2.   We then discussed the statuses of various components needed for the high-field test:

 (a) A bit more progress than what I heard from J. Hock, J. Mills reported that he'd just received the necessary drawing from J. Hock (the bolted version)
      to obtain quotes for making the Jack Support/Bracket.  

       D. Phillips told me on Sept. 27 that
       (i) The last piece of steel had been transported to the location for radiation scanning and hopefully the technicians would take away the pole tip
            from the steel today (Sept. 28) and then it'd be ready for the HP to scan.
        (ii) If welders are available (and he's got the technicians), we could do a little tapping/drilling.  When he was telling me this, he was cycling to
             look for welders to work on LeReC-related works.

 (b) Pablo Rosas told me (on Sept. 26) :

All work on the sPHENIX Power Supply and Dump Resistor had stopped since last week due to manpower work on ATR.   Hopefully they will get back to it next month.

The PS was getting ready to be connected to the new magnet load, and we were starting control wiring of the dump resistor, still need info to interface to Quench Detection System Carl Schultheiss is working on getting me the info.


(c)  I understand that C. Schultheiss (who was absent from the meeting) would want to have an overall review for the quench protection and data acquisition system (?).  
      I'm asking him when this would happen.   I mentioned that Carl would like to implement V-Idi/dt check for the quench protection even though others think that this
     might not work.   ( Carl told me that it worked in RHIC !)  Z. Altinbas was also eager to see this review happen and she told us that she'd implement it anyway as
     one of the possibilities.    Though she didn't report any particular details, she told us that the system will be there when we  need it :-)

     W. Pekrul reported that the readout for strain gauge has been done and it'll take < 1 month (2 or 3 weeks) for the quench protection system. 


(d)  Cryo group has purchased all they need and they can't do anything until the return yoke structure is in place so that they can mount their valve box etc. and connect.
      ( Most recently, they're purchasing a couple warm heaters for the +/- current leaks --- the PO of which has been pinned, and also the controller for them. )

(e) As for the cryo "Extension" work in the Central Shop, M. Anerella reported that last week when he and P. Kovach were in the Central Shop, they saw them welding
      the triangular doghouse.  So, some works have been done but there is no estimate for the completion date yet.

(f)  For the magnetic field measurement, I understand that Nils Fegee might be willing to work on this but it's not confirmed at the moment.  Ed O'Brien said yesterday that
     he'd follow up on this.



3.  As for J. Haggerty's question whether we should cool the "Extension" before lifting it 20 feet and connecting with the Magnet, M. Anerella told us that they'll
     perform leak check and also hipot (power) test.  These are the normal and standard procedures.  To cool the extension to superconducting status and then test
     will be very expensive and it's not normally done.   Other people such as R.  Than also seemed to agree.    So, the consensus is that cooling down the Extension
     to test for superconductivity on the floor before connecting with the magnet is not necessary.

4.  While discussing the Extension, people asked how to take out the Extension if it has problem.   Since D. Phillips and J. Hock were absent from the meeting,
      we could only speculate.  And then, it seems that we were not even clear how the installation sequence is or will be.
      Jon Hock's presentation some months ago (such as p.4 in
https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Past%20Presentations/2016-3-7%20sPHENIX_FE_Analysis%20(ANSYS).pptx )

showed a sequence.  But J. Mills wondered this has been changed.    J. Mills will try to organize a "calligraphy" meeting with J. Hock, D. Phillips, R. Than, P. Orfin et. al.......


5.  Following up my presentation (mentioned in (1)), people like D. Lynch, J. Haggerty and others discussed whether we could use any steel from 1006 to 1020 for the HCAL
     prototype (and beyond). 

     J. Cozzolino was curious about the complicated HCAL (our return yoke).  D. Lynch has promised to show it in our next meeting.


6. R. Than mentioned that we need to do an ASSRC/ESRC review for the coming high-field test just like for the low-field test.    I asked P. Cirnigliaro and he told me that they
   kind of have had an idea what we're going to do and things have been reviewed last time in low field test.   So, he said that the ESRC/ASSRC review should be done
  ~roughly one month before we actually do the experiment (and at that time a lot/most of your steel structures etc. have been built).




Kin