sPHENIX discussion of the superconducting solenoid

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

Hi,

 

We’ll proceed to finish the MLI for the Valvebox.  Below, I include a bit of discussion.  Paul even listed

what need to be done if we really want to do a more thorough test.   But as we discussed/decided in

our last meeting, it’s difficult to really seal the present Valvebox in a temporary way (compared to the

final manner when the chimney will join the Doghouse) without much damage (including damaging those

voltage taps/strain-gauge signal connections potentially).  Soldering and then undoing the soldering

and then soldering again at the 1008 platform may create problem.   We can fix any vacuum leak if

it’s really necessary at the platform as we’ll do the leak check there when we are done with the installation.

 

Paul’s last report was included in the last email that I sent to this mailing list but it’s here (again):

https://brookhavenlab.sharepoint.com/sites/sPHENIXMagnet/External/_layouts/15/Doc.aspx?sourcedoc=/sites/sPHENIXMagnet/External/Lists/Calendar/Attachments/285/sPHENIX_Solenoid_VB_R7.pptx&action="edit&mobileredirect=true

 

Kin

 

From: Yip, Kin
Sent: Wednesday, March 23, 2022 4:25 PM
To: Orfin, Paul <porfin AT bnl.gov>; Weiss, Dan <weiss AT bnl.gov>; Than, Yatming (Roberto) <ythan AT bnl.gov>; Ceruti, Raymond B <rayc AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Decker, Kenneth <kdecker AT bnl.gov>; Joshi, Piyush <joshi AT bnl.gov>; Mills, James A <mills AT bnl.gov>; Runyan, Christopher <crunyan AT bnl.gov>
Cc: O'Connor, Eric <eoconnor1 AT bnl.gov>
Subject: Re: sPHENIX - Valve box leak

 

Hi,

The saving grace is that we have used that Valvebox twice (one during the low-field test and another during the high-field test).

I sent Dan Weiss this (version 6) of Paul's report (which includes testing at 96 psi) :

https://brookhavenlab.sharepoint.com/sites/sPHENIXMagnet/External/_layouts/15/Doc.aspx?sourcedoc=/sites/sPHENIXMagnet/External/Lists/Calendar/Attachments/281/sPHENIX_Solenoid_VB_R6.pptx

In this report, at most we have E-7 leak.  Dan Weiss felt better after seeing this.  Cooling down may get it 100 times worse, we in principle can deal with it :-)

We have two turbo pumps (though we may use only one) in real operation on the sPHENIX platform.

Kin

On 3/23/22 14:56, Orfin, Paul wrote:

All,

 

Based on the feedback we received, we should finish MLI wrapping, proceed with Hipot testing, and prepare for closing up the valve box and move it over to 1008.  We seem to be satisfied with the low helium leak potential at this point, although some valid concerns were brought up.

 

The task of trying to do a true insulating vacuum test on the solenoid valve box would give us an official measure of total leak, helium side as well as air side.  If there is a crew available, it would be beneficial to do this but cryogenics can not spare a full time crew to support this effort.  There are advantages in working in 912 now verse 1008 with all the other activities going on around the solenoid.  Furthermore, identifying air side leak might be a worthwhile task to save time later in 1008.  Air side leaks should be low risk but there are many old seals in the solenoid that are not easily replaced.  Since it is external, we should have full access to do repairs, lowering risk. The helium side risk should be low based on our testing.  Since we are alright with accepting these risks we can proceed without the full vacuum test and wait to do these activities in 1008 with the solenoid connected.

 

For reference I have the following list to do the full vacuum test in 912 should a team become available. 

1. Cap the 3 copper pressure lines at the bottom of the chimney going to the doghouse

1. Risks to final assembly rework with soldering of caps

2. Seal the coax supply line

1. Pressure line and VJ welding of temporary caps

3. Seal the 2 large doors
4. Seal bottom chimney VJ cap
5. Install a turbomolecular pump station
6. Pump down solenoid valve box and search for air side leaks
7. Pressurize the helium lines and check for leaks with helium mass spectrometer
8. Take down this assembly before 5/27/22 when sPHENIX platform is ready for valve box

 

Let me know if we want to discuss this further. 

Thank you,

Paul Orfin
Cryogenic Systems, Collider-Accelerator Department
Brookhaven National Laboratory
Telephone: (631) 344-2899

 

From: Yip, Kin <kinyip AT bnl.gov>
Sent: Wednesday, March 23, 2022 9:49 AM
To: Weiss, Dan <weiss AT bnl.gov>; Orfin, Paul <porfin AT bnl.gov>; Than, Yatming (Roberto) <ythan AT bnl.gov>; Ceruti, Raymond B <rayc AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Decker, Kenneth <kdecker AT bnl.gov>; Joshi, Piyush <joshi AT bnl.gov>; Mills, James A <mills AT bnl.gov>; Runyan, Christopher <crunyan AT bnl.gov>
Cc: O'Connor, Eric <eoconnor1 AT bnl.gov>
Subject: Re: sPHENIX - Valve box leak

 

Hi,

I quickly chatted with Dan in his office when he's having another meeting.

I explained to Dan that we do this test without really soldering/covering all the openings in the tighest manner but only "bagging" because it'd take a lot to cover/seal all openings and it may do damage.

When we finally install the Valvebox on the platform and merge with the Magnet doghouse in 1008, at the time, things will be sealed as tight as possible at the end of the installation.   We'll do a final "leak check" at that time.

Kin

On 3/23/22 08:53, Weiss, Dan wrote:

Thanks for the summary briefing Paul.

 

I would only caution that a 1E-6 STP He background being the limit of detection could result in a ~1E-3 leak at 4K, possibly larger depending on He process line operating pressure.  Is it possible to perform a final leak test with process lines pressurized to operating pressure and cryostat evacuated?

 

Thanks,

..Dan

 

From: Orfin, Paul <porfin AT bnl.gov>
Sent: Tuesday, March 22, 2022 5:47 PM
To: Yip, Kin <kinyip AT bnl.gov>; Than, Yatming (Roberto) <ythan AT bnl.gov>; Ceruti, Raymond B <rayc AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Weiss, Dan <weiss AT bnl.gov>; Decker, Kenneth <kdecker AT bnl.gov>; Joshi, Piyush <joshi AT bnl.gov>; Mills, James A <mills AT bnl.gov>; Runyan, Christopher <crunyan AT bnl.gov>
Cc: O'Connor, Eric <eoconnor1 AT bnl.gov>
Subject: sPHENIX - Valve box leak

 

All,

 

As an action from our last meeting, we conducted a total leak rate test.  The results are promising and it seems we have repaired any significant leaks within the valve box.  Please review the attached presentation and let us know if you agree so we can proceed with next steps in getting the valve box ready for 1008. 

 

Thank you,

Paul Orfin
Cryogenic Systems, Collider-Accelerator Department
Brookhaven National Laboratory
Building 1005S, MS 1005S, Room 217
Upton, NY 11973-5000
Telephone: (631) 344-2899
Fax: (631) 344-3329 
E-mail: porfin AT bnl.gov