Re: [Fwd: RE: question]

[Elke-Caroline Aschenauer <elke@jlab.org>]

On Tue, 15 Jul 2008, Leigh Harwood wrote:

Dear Leigh and Yves,

first of all let me thank you both for keeping Hall D / GlueX so nicely
informed about these new calculations. It is highy appreciated.

Actually I have a couple of some questions to the new calcualtiosn, which
indeed look very very promissing.

I must admit I have a really hard time believing that there no
non-gaussian tails.
That is really suprising at least if I use my experience from HERA, yes
Cebaf is not HERA, but there is synchrotron radiation and yes I know Cebaf
has less synchrotron radiation compard to HERA ((E2-E2)^4), because of the
lower beam-energy, but CEBAF keeps the radius in the arcs the same with
doubling the beam energy, this should increase the synchrotron radiation
more than just what you would expect from the energy difference. I also
know the number of turns is less than in HERA, but again no non
gaussian tails at all. There is misalignement of the magnets
which widens your emittanceand their is rest gas, which actually inreases
because of the increased synchrotron radiation.
So all this effects populated tails, apart from the misalignement, this
increases the emittance and if it is really bad can increase the
synchrotron radiation, because a lot of particles go of center through
the quad fields.
So my question is are all this effects simulated.

Please don't misunderstand my mail I don't want to be negative on the
results, but woud like to understand a bit better how the simualtions are
done. I think it would be also nice to have the energy spectrum going
together with this new spatial distributions of the beam.

Thanks and have a nice evening
elke



> Date: Tue, 15 Jul 2008 21:04:51 -0400
> From: Leigh Harwood <harwood@jlab.org>
> To: elke Aschenauer <elke@jlab.org>
> Subject: [Fwd: RE: question]
>
> Elke,
>
> I asked Yves to calculate the number of particles outside the diamond
> (+/- 5mm) and outside the inned edge of the frame (said to be +/- 7.5mm)
> The results are below.
>
> I'm not sure I believe them!
>
> L
>
> -------- Original Message --------
> Subject: 	RE: question
> Date: 	Tue, 15 Jul 2008 11:31:29 -0400
> From: 	yves roblin <roblin@jlab.org>
> To: 	'Leigh Harwood' <harwood@jlab.org>
> References: 	<487C2CD2.7080605@jlab.org>
> <000801c8e688$34bdbdd0$9e393970$@org> <487CC0D1.9000806@jlab.org>
>
>
>
> Leigh,
>
>
>
>   Here are the numbers :
>
>
>
>
>                                     DIMAD
>   ELEGANT
>
> Past 5mm
>                      35150                                            1504
>
> Past 7.5mm
> 10583                                            0
>
>
>
>
>
> At first glance, looking at the plot it did not look that it would be
> that much in DIMAD. However,
>
>  I checked in the file and there are many bins and they are in the
> dozens or hundreds counts..
>
>
>
> The counts were calculated for each plot independently (not aligned
> together).
>
>
>
> Yves
>
>
>
>

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