[PEPPo] TN re positron solenoid

[Jay Benesch]

Probir,

Slide 8 of Andriy's presentation shows 0.6 W energy deposited in the 
solenoid assuming the W10Cu absorber intercepting 7.4 kW.  My draft 
suggests replacing the 5 cm of W10Cu before the solenoid with 15 cm 
steel down to 20 cm IR with TBD W10Cu outside that.  Until the FLUKA 
model is re-run with revised shielding and a 3D field map one can't say 
whether the power to the solenoid will be 0.6 W or 6 W or more.  I 
therefore suggest a conductor which would have more margin at 5 K than 
NbTi would.  Also I worried about neutron dose.  Modern NbTi is so 
pinning-optimized that neutron dose will likely degrade it rather than 
enhance as in the very old days.

I can't say whether it would be easier to get development funding from 
DOE for a conventional or conductively cooled SC unit with HTC.  The 
commercial 4T Moller polarimeter magnets have not been as stable as one 
would like, with minimal beam scatter.  I lean towards conventional but 
wanted to address Sergei's suggestion.  Power supply would be a lot 
cheaper with SC.

Jay

On 10/17/23 10:45, Probir Ghoshal wrote:
> Dear Jay,
> 
> The analysis seems reasonable, but the thing stuck to my mind is using 
> cryo-cooler and conduction cooled, is good but why MgB2 and why not NbTi 
> (the max field you are looking for is ~3T and reasonably small bore)...?
> The writeup/notes does not specify what is the requirements are (units 
> used in the Visual graphics, x,y,z B, etc.).
> 
> 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:* Tuesday, October 17, 2023 10:34 AM
> *To:* Kim Edwards <kindrew at jlab.org>
> *Cc:* peppo at jlab.org <peppo at jlab.org>
> *Subject:* [PEPPo] TN re positron solenoid
> for the repository