[PEPPo] positron capture magnet

[Jay Benesch]

Probir,

At the Ce+BAF meeting yesterday, Andriy showed radiation and power 
deposition information including tungsten shielding inside and outside a 
copper coil 30 cm long, 30 cm IR, 40 cm OR, ~1.8T.  Recalling my MRI 
days, I suggested replacing some of the tungsten with steel at the 
meeting.  Andriy's slides are at
https://jeffersonlab.sharepoint.com/sites/PositronSource/SitePages/2023-10-11-Ce+BAF-Meeting.aspx 


Yesterday afternoon I decided to try my hand at it.  I found that I 
needed much more copper radial extent and a lot more steel than 
suggested Wednesday.  Andriy may choose to rerun his models with what I 
outlined, adding tungsten as needed.  There's also a French collaborator 
who's looking into an SC magnet which would be shielded by internal 
W10C.  I agree that 1.8 T is optimistic.

Space and other operating conditions are implied in Andriy's slides.  If 
you don't have access to the sharepoint, Joe or Andriy should be able to 
add you.  If it's in LERF the beam line is now 70 cm off the floor as in 
CEBAF; this can move up to center between floor and ceiling.

Jay

On 10/12/23 11:15, Probir Ghoshal wrote:
> Great Jay,
> First hand look and my initial thoughts...!
> 
>  1. 10 A/mm^2 is not bad...
>  2. 1.8 T seems optimistic, what impact does this have to physics with
>     1.7T ?
>  3. What are the space constraint(s)/limitations...?
>  4. What are the operating conditions viz environment (temperature)
> 
> Regards
> Probir
> 
> *Probir K Ghoshal*, PhD.
> Magnet Group Leader, Experimental Nuclear Physics
> /Jefferson Lab
> 600 Kelvin Drive, Suite #3, 55C
> Room #2545, Newport News, VA 23606 (USA)/
> 
> Telephone: 757 269 6702 (office)
> Mobile: 518 334 3289
> email: ghoshal at jlab.org
> 
> 
> ------------------------------------------------------------------------
> *From:* PEPPo <peppo-bounces at jlab.org> on behalf of Jay Benesch via 
> PEPPo <peppo at jlab.org>
> *Sent:* Thursday, October 12, 2023 10:10 AM
> *To:* peppo at jlab.org <peppo at jlab.org>
> *Subject:* [PEPPo] positron capture magnet
> I did a quick and dirty model of a water cooled copper capture solenoid
> 30 cm long with 30 cm IR and steel outside 20 cm IR.  In order to get
> 1.8 T peak I had to increase the current density to unacceptable levels
> with 10 cm radial extent so that is 24 cm in the attached.  Current
> density 1000 A/cm^2 in coil pack, that in the copper will be larger.
> Steel is 15 cm thick and still well into saturation.  There's a 1 cm gap
> between coil and steel.  Field at [0.0,-50] 1260 G, about a fifth of
> what Andriy showed.  Default "good magnet steel" BH curve used. Field
> will be a few percent lower if 6" cold rolled steel of easily available
> grade is used.