sPHENIX discussion of the superconducting solenoid

["Ceruti, Raymond B" <rayc AT bnl.gov>]

Hi All,

      After our unsuccessful pressure leak test this morning we dropped the lower vacuum can (the easy one to remove) and sniffed all the joints that were accessible.  Those joints were found to be not leaking but with the probe inserted up into the heat shield from below, the leak detector dropped down a decade.  This seems to indicate that our leek is more than likely in the upper area.  I would suggest that we remove at least one door and pump on the helium line in an attempt to locate this leak.

Regards,

Ray    

 

From: sphenix-magnet-l-bounces AT lists.bnl.gov [mailto:sphenix-magnet-l-bounces AT lists.bnl.gov] On Behalf Of Kin Yip
Sent: Thursday, September 03, 2015 10:59 AM
To: sphenix-magnet-l AT lists.bnl.gov
Subject: [Sphenix-magnet-l] leak in the He pipeline of Valve Box (2nd trial)

 

 

Hi,

After gathering M. Gaffney and the safety people, Ray Ceruti and his team pumped in He (to the max. of 6.6 bar) to do the pressure test. 
Before the pressure test, the vacuum pressure was at the level of something like 7*10-9 mbar or so.  But after pumping in He, the pressure
reached 10-3 mbar in about 10 minutes.   So, there is a leak (though may not be huge).   [  In the process, they found a O-ring outside that
was burst but that's not the reason   as it's between the outside atmosphere and the valvebox (not between the He pipeline and inside valvebox. ]

Ray et. al. now need to find it (by breaking up the system piece by piece) ... I have the impression that it's not easy ......

Kin