sPHENIX discussion of the superconducting solenoid

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

Hi,

The following may be  redundant but I promised to my other colleagues that 
I'd pass along the message and so I'm writing now.

In the attached pptx, you could see that the Cryo Group has found a vacuum 
leak at the soldering joint of the current lead (+).    They had 
re-soldered it since   to fix this leak.   ( The leak/crack has never been 
visible ... so ~microscopic. )

I remember that there was a short period of time before our High Field test 
(which happened in early 2018), that the 535 MCM cables were ~directly 
connected to the current leads 
without a support structure.  Then, Carl Schultheiss and others "complained" 
and then you kind of helped us put in a support structure (right on the spot 
and in short order) so that the 
cables would not be pulling at the current leads.   I wondered whether that 
short period of time (before your support structure) had done some "damage".

In any case, the message is that: since you're going to do something similar 
again,  please try your best to minimize any force on the current lead from 
the 535 MCM cable.   Even when 
you install the copper block, please try not to cut into the solder at the 
joint to avoid creating any microscopic/invisible crack.

Kin

Attachment: sPHENIX_Solenoid_VB_R6.pptx
Description: sPHENIX_Solenoid_VB_R6.pptx