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Re: different quad for the tagger



On Mon, 8 Dec 2008, Jim Stewart wrote:

Dear Jim,

very nice, you know like at BNL the guy who saved the 100M$ did not get a
significant fraction of it as income ;)

But not jocking. Do we need to check the smaller beam-pipe will change
anything for our background simulations?

Cheers elke



> Date: Mon, 08 Dec 2008 14:31:55 -0500
> From: Jim Stewart <jstewart@jlab.org>
> To: tagger list <halld-tagger@jlab.org>
> Subject: different quad for the tagger
>
> 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
>

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