sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Hi,

Just in case in 10 years' time, I will be wondering about what the picture shows => so let me write the following

down to explain to myself :

(1) Before we put in any volt (i.e., at 0V), somehow, this meter already would show ~30 micro-amp. ( I've seen a

few meters of Carl's group. Each one may have slightly different "character"/feature. ) So, at the end, we

saw 60 micro-amp => the leakage current is ~ 30 micro-amp.   (519 V) / (30 micro-amp) is ~ 17.3 MOhm which

seems a big no. and Carl thinks it's good enough :-)

(2) We intended to go to 520 V (setting the ramp at the 5V/s steps etc.) but somehow the intrinsic "programming" fault (according to Carl) made it go to 519 V only 😅  Since everything is automatic (as it'd go up, dwell for a minute and

go down according to a continuous flow/program), one couldn't just add 1 V by hand.  So, that's why the picture showed,

519 V.   [ None of us think that this discrepancy matters 😁 ]

Kin

-------- Forwarded Message --------

Subject:	Carl did another hipot → leak check
Date:	Wed, 27 Jul 2022 15:29:26 -0400
From:	kinyip AT bnl.gov
To:	sphenix-magnet-l AT lists.bnl.gov
CC:	Sheth, Chintan <csheth AT bnl.gov>, O'Connor, Eric <eoconnor1 AT bnl.gov>, Decker, Kenneth <kdecker AT bnl.gov>, Warkentien, Andreas F <andyw AT bnl.gov>

Hi,

Before 3 pm, Carl did another hipot successfully for the Magnet.

This time, Carl and his tech brought a fancier meter and the ramp was finished in 104 seconds (as it is 5V / s).  We dwelled for 1 minute.  I took a picture of their setup.

So now, the cryo/vacuum group can do the leak check.

( I am thinking ... The obvious places for leaks includes the doors and the connector underneath the Doghouse because it was turned 90 deg. earlier this week 😀 )

Kin

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