sPHENIX discussion of the superconducting solenoid

["Mills, James A" <mills AT bnl.gov>]

Hi Mike,

 

Jon did an ANSYS simulation for the cryostat under vacuum and got a maximum deflection of about 3 mils.  This is in the ball park of what we were thinking in regard to pre-loading the jacks so that they would stay engaged.  This is what we have been pondering all week (and I think Dave talked with you briefly about it).

 

I sent out two emails to SLAC and got one response from a senior tech who was one of our points of contact, Mike Racine.  He said he was not involved with the installation of the cryostat into the flux return steel. My other contact, Wes Craddock has not responded.  I did find a document in our BABAR library out at 1008 that appeared to be a second version of their installation procedure, where they discuss the jacks.  From the way I read it, they pre-loaded the axial supports but essentially just snugged up the radial supports.  I have enclosed it for you in this email.

 

So, I think that if we snug up the jacks after we start pumping down, we ensure that the jacks are engaged for the test.  Before we bring the vacuum up to atmosphere, after the test, we can release the top and side jacks.  But I think the maximum preload (if we return to atmospheric conditions) we will see will be on the order of 3 mils.  One things we plan on doing though is that we are going to install linear pots to monitor both relative axial as well as radial movement of the cryostat with respect to the support jacks (at least that is the plan).  We will also monitor the temperature inside the steel box and if we see a large swing in temperature (as we start to do the test) we will stop to figure out what is happening and whether it will have an effect, possibly changing any internal stresses on the cryostat.

 

At least that is the plan…..what do you think Mike?

 

Thanks,

Jim

 

 

 

From: Anerella, Michael D
Sent: Friday, November 17, 2017 9:45 AM
To: Yip, Kin; Orfin, Paul; Ceruti, Raymond B; Mills, James A; Hock, Jonathan
Cc: sphenix-magnet-l AT lists.bnl.gov
Subject: RE: Start insulating vacuum pump down

 

If you tighten supports after you develop vacuum do you loosen them before you dump vacuum?  Is this what SLAC did?

 

 

 

From: sPHENIX-magnet-l [mailto:sphenix-magnet-l-bounces AT lists.bnl.gov] On Behalf Of Yip, Kin
Sent: Friday, November 17, 2017 9:42 AM
To: Orfin, Paul; Ceruti, Raymond B; Mills, James A; Hock, Jonathan
Cc: sphenix-magnet-l AT lists.bnl.gov
Subject: Re: [Sphenix-magnet-l] Start insulating vacuum pump down

 

Hi,

 

Jim just sent me email that they are waiting for you to start pumping down so that they can do the final tightening of the Cryostat supports.

 

Ray already closed the doghouse yesterday as our email(s)  indicated.  Nothing should prevent you from pumping down now.

 

Kin

 

 

------ Original message------

From: Orfin, Paul

Date: Fri, Nov 17, 2017 22:26

To: Ceruti, Raymond B;Mills, James A;Hock, Jonathan;Yip, Kin;

Cc:

Subject:Start insulating vacuum pump down

 

 

All,

 

I want to verify we can start pumping down the insulating vacuum.  We are testing now but would like to leave it on when we are done.

 

 

Thank you,

Paul Orfin
Cryogenic Systems, Collider-Accelerator Department
Brookhaven National Laboratory
Telephone: (631) 344-2899
E-mail: porfin AT bnl.gov

Attachment: Installation.pdf
Description: Installation.pdf

--- Begin Message ---

• From: "Hock, Jonathan" <jhock AT bnl.gov>
• To: "Mills, James A" <mills AT bnl.gov>, "Phillips, David B" <phillips AT bnl.gov>
• Subject: cryostat displacement under vacuum
• Date: Wed, 15 Nov 2017 19:50:01 +0000

Jim,

 

The max displacement under vacuum is .014”  located on the id ( first graph) . Where the axial supports engage the end plate, the displacement is  about  -.0014” in the axial direction (2^nd graph). For the top radial jack the cryostat moves .003” away from the jack (graph 3). The radial displacement at the side jacks is .0009”(graph 4).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Jon Hock

Brookhaven National Labortory

631-344-7506

 

--- End Message ---