sPHENIX discussion of the superconducting solenoid

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

Hi Kin and Wuzheng,

 

Thank you very much.  Yes, we (Jon Hock and I) were looking to reduce the weight of the cradle carriage and I believe that there were some calculations done that suggested we could thin down the pole tips to 19 cm (~7.5 inchs) without overly saturating the steel.  So we have been looking for 7.5 inch to 8 inch plate to do the job for us. 

 

Thanks,

Jim

 

From: sPHENIX-magnet-l <sphenix-magnet-l-bounces AT lists.bnl.gov> On Behalf Of Yip, Kin
Sent: Friday, October 12, 2018 10:16 AM
To: Meng, Wuzheng <meng AT bnl.gov>; sphenix-magnet-l AT lists.bnl.gov
Subject: Re: [Sphenix-magnet-l] Forces on the wheels (of TPC)

 

Hi Wuzheng,

Can you please answer Jim Mills' question about the thickness of the endcap ?   Now, they're building a 8" one, not the 30 cm in your old model.  Do you think it matters significantly ?
[  I made one 19 cm :   ~kinyip/Meng/sphenix_m1q_dz=0_24-coils_poletip19cm.oppre, by reducing the thickness of 30 cm one, in Feb. 2017.   19 cm ~ 7.48 inches.   The engineer at the end
chose to use 8 inches. ]

For the field collapse, I'd think it's as fast as the change of current travels, which is like a fraction of the speed of light ?!   Too fast for us to worry about the uniformity of collapse or not.
This is DC (no rise time), an electrical engineer told me to just assume that it's instantaneous.  Wuzheng, if you have any additional comment, please do give here generously.

Kin

On 10/12/2018 09:15 AM, Mills, James A wrote:

Hi Kin and John,

 

I was wondering, when the field collapses due to a quench, does it happen uniformly and simultaneously along the length of the coil or does it happen at one end, moving across the length to the other end?  Or does it happen from the longitudinal center and then propagate to each end simultaneously?  It is interesting and I have never thought about it before. 

 

Does it matter how the quench occurs?

 

Thanks,

Jim

 

From: Mills, James A
Sent: Friday, October 12, 2018 9:12 AM
To: Yip, Kin <kinyip AT bnl.gov>
Subject: FW: Forces on the wheels (of TPC)

 

Hi Kin,

 

FYI,

 

Jim

 

From: Cozzolino, John
Sent: Friday, October 12, 2018 8:24 AM
To: Lynch, Don <dlynch AT bnl.gov>; Mills, James A <mills AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Bellavia, Steven <bellavia AT bnl.gov>
Cc: 'hemmick AT skipper.physics.sunysb.edu' <hemmick AT skipper.physics.sunysb.edu>; Klaus Dehmelt (klaus.dehmelt AT stonybrook.edu) <klaus.dehmelt AT stonybrook.edu>
Subject: RE: Forces on the wheels (of TPC)

 

Hi Don,

 

I applied a 130 lbf axial force to the inside face of the wagon wheel (with no GEM assemblies installed) and looked at the resulting axial deflections.  It is supported by the tie rod lugs at the OD so the maximum axial deflection is at the ID.  Is 1.6 mils manageable?  I would assume it is.  See attached screen capture which shows 1/24’th of the circumference. 

 

If there’s anything else you need, please let me know.

 

Regards,

 

John

 

From: Lynch, Don
Sent: Thursday, October 11, 2018 12:08 PM
To: Cozzolino, John <cozz AT bnl.gov>; Mills, James A <mills AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Bellavia, Steven <bellavia AT bnl.gov>; Ruga, H Andres <ruga AT bnl.gov>; Ruggiero, Richard <ruggiero AT bnl.gov>
Cc: 'hemmick AT skipper.physics.sunysb.edu' <hemmick AT skipper.physics.sunysb.edu>; Klaus Dehmelt (klaus.dehmelt AT stonybrook.edu) <klaus.dehmelt AT stonybrook.edu>
Subject: Re: Forces on the wheels (of TPC)

 

Hi John,

 

Looking at Wuzheng’s PPT, I would take it that the force is axial, distributed across the inner face of the wheel (like a pressure) and directed outward from the center of the detector. The total force is ~ 130 lbs. It looks like the forces are approximately the same on the north and south wagon wheels, in both cases pointing outward.

 

-Don

 

From: "Cozzolino, John" <cozz AT bnl.gov>
Date: Thursday, October 11, 2018 at 12:01 PM
To: "Mills, James A" <mills AT bnl.gov>, Microsoft Office User <dlynch AT bnl.gov>, "Anerella, Michael D" <mda AT bnl.gov>, "Bellavia, Steven" <bellavia AT bnl.gov>, Andres Ruga <ruga AT bnl.gov>, Richard Ruggiero <ruggiero AT bnl.gov>
Cc: "'hemmick AT skipper.physics.sunysb.edu'" <hemmick AT skipper.physics.sunysb.edu>, "Klaus Dehmelt (klaus.dehmelt AT stonybrook.edu)" <klaus.dehmelt AT stonybrook.edu>
Subject: RE: Forces on the wheels (of TPC)

 

Hello All,

 

Can you distill this all down to a set of forces, point() or surface(s) of application on the wheel, and direction for me?  Then I’ll run some FE on it.

 

Thanks,

 

John

 

From: Mills, James A
Sent: Thursday, October 11, 2018 2:43 AM
To: Lynch, Don <dlynch AT bnl.gov>; Cozzolino, John <cozz AT bnl.gov>; Anerella, Michael D <mda AT bnl.gov>; Bellavia, Steven <bellavia AT bnl.gov>; Ruga, H Andres <ruga AT bnl.gov>; Ruggiero, Richard <ruggiero AT bnl.gov>
Cc: Mills, James A <mills AT bnl.gov>; 'hemmick AT skipper.physics.sunysb.edu' <hemmick AT skipper.physics.sunysb.edu>; Klaus Dehmelt (klaus.dehmelt AT stonybrook.edu) <klaus.dehmelt AT stonybrook.edu>
Subject: FW: Forces on the wheels (of TPC)

 

Hi guys,

 

Some results from Wuzheng on the forces that act on the TPC Wagon Wheels during a magnet quench.  I have not studied the results yet but wanted to forward them to you for your review.

 

Thanks, have a great day.

Jim

 

From: sPHENIX-magnet-l <sphenix-magnet-l-bounces AT lists.bnl.gov> On Behalf Of Yip, Kin
Sent: Wednesday, October 10, 2018 9:29 PM
To: Haggerty, John <haggerty AT bnl.gov>
Cc: sphenix-magnet-l AT lists.bnl.gov
Subject: [Sphenix-magnet-l] Forces on the wheels (of TPC)

 

Hi John,

 

Please find here:

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Shared%20Documents/Dr.%20Meng%20Wuzheng's%20calculations/2018-10-10%20Wheel_eddy_curr_force.pptx

 

Wuzheng’s calculation of the forces on the two wheels here.   Are those hundreds of tons manageable  ??

 

{ By the way, Wuzheng doesn’t charge us the time that the Opera has taken to calculate, many days 😊  }

 

Kin

 

From: Meng, Wuzheng
Sent: Wednesday, October 10, 2018 9:24 PM
To: Yip, Kin <kinyip AT bnl.gov>
Subject: RE: Modified power point file

 

Hi,

 

Thanks for your time!

 

Wuzheng

 

From: Yip, Kin
Sent: Wednesday, October 10, 2018 9:22 PM
To: Meng, Wuzheng <meng AT bnl.gov>
Subject: RE: Modified power point file

 

Hi,

 

Looks good !  Thanks !  … I’ll send it to the sPHENIX Magnet mailing list …

 

Kin

 

From: Meng, Wuzheng
Sent: Wednesday, October 10, 2018 8:08 PM
To: Yip, Kin <kinyip AT bnl.gov>
Subject: Modified power point file

 

Kin,

I modified page 4 and 6. I keep the same file name.

How is the new one?

Wuzheng