sPHENIX discussion of the superconducting solenoid

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

Dear All,

 

Ray would meet with me at 912 around 11 am to 11:15 am.   I include the documentation from BaBar.  

 

Kin

 

From: O'Connor, Eric <eoconnor1 AT bnl.gov>
Sent: Thursday, March 10, 2022 10:32 AM
To: Yip, Kin <kinyip AT bnl.gov>
Cc: Ceruti, Raymond B <rayc AT bnl.gov>; Orfin, Paul <porfin AT bnl.gov>; Than, Yatming (Roberto) <ythan AT bnl.gov>; Decker, Kenneth <kdecker AT bnl.gov>
Subject: Solenoid VB Leak Finding - Update

 

Good morning, Kin

 

After another recent leak test, we were able to get the vacuum level down to 10E-5 level, which was an improvement. Helium background was recorded at 10E-6. Internal leaks are taken care of and extremely minimal, however, we found one major leak source externally on top of the valve box. The solder used to join the (+) lead to the block has been gashed and cracked through as indicated by the picture below. The helium background rose to the 10E-4 range from 10E-6. The vacuum group believes this is because the copper block bolted onto this block is too large and flush to the cylindrical lead and cracked the solder. One future recommendation is to machine these attaching blocks to prevent this from occurring for the (+) and (-) leads.

 

However, this poses a question for the magnet division – what are the internals inside? We want to know if we can use a Grade 5 solder for this copper to SS transition, Indium solder, torch/weld over the existing solder, etc. We don’t want to damage any internals with the high heat based on the melting points of our options.

 

If you guys are around today, perhaps we can meet with the vacuum group at 912 today to discuss a solution to get the ball rolling. Once this is fixed, we can proceed with a pressure test. Please give me a call on my cell/office to coordinate or have any questions. Thank you.

 

Regards,

 

Eric O’Connor

Associate Staff Engineer

Cryogenic Systems, Collider-Accelerator Department

Brookhaven National Laboratory

Telephone: (631) 344-8952

Cell: (631) 546-8842

E-mail: eoconnor1 AT bnl.gov

 

Attachment: 2.3.1 He Cooled Current Leads.pdf
Description: 2.3.1 He Cooled Current Leads.pdf

Attachment: 6.3 CHIMNEY, VALVE BOX AND ELECTRICAL EXIT.pdf
Description: 6.3 CHIMNEY, VALVE BOX AND ELECTRICAL EXIT.pdf