Re: different quad for the tagger

["Curtis A. Meyer" <cmeyer@ernest.phys.cmu.edu>]

Hi Jim -

  that looks very interesting.  Do we have a feeling what the smaller
apperature would do to us? 

  cheers - Curtis
On Mon December 8 2008, Jim Stewart wrote:
> Dear Colleagues
> 
> I believe I have found some quadrupoles available here at JLAB which 
> would be
> usable for the  tagger. The quadrupoles from the Helios transfer line 
> are available
> for us to use. I think we can use two of these quadrupoles for the 
> focusing magnet
> in the tagger. The specifications of the quadrupoles are given below 
> along with the
> requirements in the present design and the specifications on the WIKI. 
> Two of the
> Helios quadruples would be able to provide 14 T/m gradient over 400 mm 
> length.
> The present design calls for 5.2 T/m over 313mm. Therefore the Helios 
> quadrupoles would need
> to run at 4.1 T/m in our present design. This is 3.4 times less than 
> their max rating. This
> should be enough. Does anyone know why the WIKI spec call for 20T/m and 
> 400mm?
> The Helios magnets only have a aperture of 20 mm which is substantially 
> smaller than the
> 30mm in the WIKI spec. At present we are planning to use a 25mm beamline 
> through these
> quads so we would have to go to a smaller diameter pipe.
> 
> The big advantage of these magnets is that they are free and we then 
> save 20K$.
> 
> 
> Jim
> 
> 
> Helios quadrupoles:
> =======================================
>    Aperture diameter                         20 mm ± 2mm
>    Magnetic length                             200 mm
>    Max magnetic field gradient           14 T/m
>    Field Uniformity                            1%
>    Ampere Turns                               2508 A-T
>    Maximum Current                         19A
>    Maximum Power consumption      192W
> 
> 
> Present Design:
> =============
>    Aperture diameter                         36.2 mm
>    Magnetic length                             313 mm
>    Max magnetic field gradient           5.2 T/m
> 
> 
> 
> Wiki Spec
> ====================================
>   Aperture diameter                         30 mm ± 2mm
>    Magnetic length                            400 mm
>    Max magnetic field gradient          20 T/m
> 



-- 
Professor Curtis A. Meyer        Department of Physics
Phone:  (412) 268-2745          Carnegie Mellon University
Fax:    (412) 681-0648            Pittsburgh PA 15213-3890
cmeyer@ernest.phys.cmu.edu  http://www.curtismeyer.com/