sPHENIX discussion of the superconducting solenoid

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

Hi,

 

We have a meeting today (from 11 am to 12 pm) discussing about the Valvebox leak check and what to do next.

 

Paul showed two of his powerpoints about their leak check works for the Valvebox:

 

https://brookhavenlab.sharepoint.com/sites/sPHENIXMagnet/External/_layouts/15/Doc.aspx?sourcedoc=/sites/sPHENIXMagnet/External/Lists/Calendar/Attachments/278/sPHENIX_Solenoid_VB_R5.pptx&action="edit&mobileredirect=true

 

https://brookhavenlab.sharepoint.com/sites/sPHENIXMagnet/External/_layouts/15/Doc.aspx?sourcedoc=/sites/sPHENIXMagnet/External/Lists/Calendar/Attachments/281/sPHENIX_Solenoid_VB_R6.pptx&action="edit&mobileredirect=true

 

1. One point Paul made was that we should be careful not to exert any force on the current leads to prevent any vacuum leaks.  I’ll pass it to Rob Karl and Dave Chan.
   
   
2. The Cryo group fixed one ceramic (electrical) insulator/break (and Ray Ceruti replaced one in 2015 before our low-field test) in the Valvebox on the +ve side.  There are two more on the -ve side.
   We discussed whether to replace the other two which are good and not leaking.   Joshi suggested that we replaced those two as well.  But other people have the feeling that

if they are not broken, we should not try to fix them.   And as Carl asked, Paul told us that we can fix them when the Valvebox is installed in the platform in 1008 if it’s really necessary.
It’s almost as easy/difficult as now (though we need to open the Valvebox of course).

3. In the meeting, we’ve had the consensus that the vacuum leak checks for different helium lines performed should be considered as sufficient and complete.
   
   
4. The Cryo group is implementing the MLI (multi-layer-insulation).   Ray Ceruti suggested that we put in 2 layers of Kapton for insulation to avoid the MLI conducting any electricity to the ground.

 

5. Carl Schultheiss will write a green-sheet for the coming hipot test and  Piyush Johsi will make some sort of traveller for the hipot test so that the tech. performing the hipot can fill out the traveller.
   We will do this after the Cryo group finishes wrapping the MLI.  The hipot may happen next week.

 

6. At the end, we spent some time to discuss whether we should close the Valvebox up and do a vacuum test for the entire Valvebox (which would mean checking helium leak and air leak).  For that, we need
   to close out the entire Valvebox including the bottom of chimney.   We may need to solder to cap it and re-solder to open it again.   This seems to be too intrusive as there are some wires (strain gauge/voltage taps)
   near the electrical busses.   The temporary seals are not “real” anyway as in the final version, the busses and wires in the chimney is connected with the junction-box/doghouse of the Extension.
   
   Roberto Than, at the end, suggested that instead of doing the above test, we just kind of do a more thorough helium leak check by for all the helium paths in the Valvebox so that we don’t need to really close the Valvebox but somehow “bag” it for the helium test.    This seems something that we can do not too difficultly.

 

Kin