sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

First of all, a very personal/subjective feeling here:

This meeting is a candidate for the most productive meeting of all 
sPHENIX Magnet biweekly meetings (so far).


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Powerpoint/Agenda page: 
https://indico.bnl.gov/conferenceDisplay.py?confId=2269

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1. Today's meeting is mainly about the placement of voltage taps and 
temperature sensorsfor the Cryo extension (the component of which is 
being made in the BNL central shop).

Paul Giannotti's very useful powerpoint presentation (39 MB) can be 
found in the above indico page as well as at the top of the "past 
presentations" page of our sPHENIX Magnet webpage :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Past%20Presentations/


In the meeting, Paul showed us his understanding of the voltage taps and 
temperature sensors with pro-E drawings from Paul Kovach, photos of the 
existing system as well as his own design/schematic drawings.   He's 
proposed to add 12 new voltage taps (VT18-VT29) in addition to the 
existing (VT01 - VT17)and there was no objection to his proposal.

We have spent quite some time discussing how to route the new voltage 
tap cables out of the system(extension/valve-box/doghouse). Paul first 
suggested to route the cables through an existingcross as shown in page 
15 of his presentation by making new connections.  Paul Orfin commented 
that he needed to check with Richard Meier to see whether there is 
enough room left there.  But later, Paul Kovachsuggested using flanges 
at the doghouses/junction-box so that the cables can come out directly 
from the doghouse instead of routing all cables through the entire 
extension.

The old doghouse has a flange that we can use but Ed O'Brien and Don 
Lynch told us that there is not enough room as they're surrounded by the 
HCAL.  Don said that we don't even have enough space to put the flange 
at the side and let cables coming out at 90 deg.

So, it's decided to put a new flange at the new doghouse and Paul Kovach 
said that it's an easy enough task to do.  He'll modify his extension 
drawings and send to central shop to make this modification.

The voltage taps will be added when the extension components (made by 
the Central Shop) are being assembled in Bldg. 902.


2.  We then discussed about the temperature sensors.   The cryo group 
has planned to add 4 temperature sensors as shown in Paul Giannotti's 
presentation page 2 (TE1786H, TE1787H, TE1788H & TE1789H) at the joints 
of both ends of the extension (for both + and - paths).  Cryo group is 
using the CERNOX type of temperature sensor.  [ The Cryo group had 
already planned to add two for the low current test but they were not 
added because that location was wrapped before they could manage to 
install the sensors.

Carl Schultheiss suggested to add a total of 2 more temperature sensors, 
each next to the (He) outlet beneath both the current leads, for 
diagnostic/debugging purpose when we see a quench or something wrong, 
even though the voltage taps would tell us about the quench (etc.) 
before the temperature sensors.

However, Paul Giannotti told us that those are wrapped inside the 
chimney and are not accessible unless we break open the chimney and all 
those wrappings.  People felt that this was an action too risky to 
take.  Furthermore, Joe Muratore (who has been very experienced in the 
diagnosing magnet quenches or other problems) told us that the voltage 
taps actually may tell us more than the temperature sensors and he 
felt/thought it's enough to have the voltage taps (without the 
additional temperature sensors) if it's impractical to add the 
temperature sensors.

So, it's decided not to add additional temperature sensors. Peter 
Wanderer and Joe promised that Joe will come to debug/diagnose the 
problem when the sPHENIX Magnet has a problem like that in the future :-)



3a.  I mentioned that, through email communication with John Cozzolino, 
John told me that after changing the "current" to "current densities" in 
his ANSYS Maxwell model, John's simulation/calculation now obtain a 
central field  very close to Wuzheng's (and the real measurements that 
we have had at 100 A test).   John told us now, he's using the new 
B-field results (in 2D) and going through the ANSYS stress analysis.  
He's comparing  this all-ANSYS result with his stress analysis results 
that he used Wuzheng's B-field/force (from Opera) as input to ANSYS' 
stress analysis.  He'll probably show us in the next meeting.

3b. This coming Friday (July 22), there will be a small 
discussion/review with Pablo Rosas' changes on the sPHENIX Magnet Power 
Supply (originally from BaBar) such that Pablo will show a few of us 
(including some power supply experts) his changes to the power supply.

3c. Carl Schultheiss has also promised to show us (including Bob 
Lambiase) a scheme of the quench detection/DAQ for the full-field test.  
He said this may happen in a couple of weeks.



4. Jim Mills asked about the scheduling.  I informed people that the 
Cryo group (Paul Orfin/Roberto Than) has sent their changes to the old 
version of the Microsoft Project file and I've passed them to Dave 
Phillips.   Frank Achim (who has just got back from vacation) and Carl 
haven't done the scheduling modification yet.  Carl said he'll make the 
changes after discussing it with Pablo, esp. after the above-mentioned 
Friday's review.   Dave Phillips told me after the meeting that he still 
thinks the welding is the critical path --- here we assume that the 
extension works will be done on time.

4.1  Ed O'Brien has asked me to ask Jon Hock for his cost estimate for 
the welding and bracket etc. for the return yoke (for full-field 
test).   I sent an email when I couldn't find Jon.  But just before 
writing this, I met Dave and Jon and Jon said that he'll do this on 
Friday (as he had to work on the ERL-related stuff tomorrow on Thursday).