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Re: new simulations for fdc



On Tue, 5 Jun 2007, Kornicer,  Mihajlo wrote:

Dear Mihajlo,

thank you very much for the answer, I guess we wil ldiscuss some details
during the software meeting, because you plots currently give an overview
over tha overall performance of the detector, but at least for the
optimization effort of the FDC material we need a bit different
information.

Talk to you soon,
elke


> Date: Tue,  5 Jun 2007 11:20:40 -0400
> From: "Kornicer,  Mihajlo" <mikornic@indiana.edu>
> To: Elke-Caroline Aschenauer <elke@jlab.org>
> Cc: halld-tracking-hw@jlab.org, halld-cal@jlab.org, HallD-Offline@jlab.org
> Subject: Re: new simulations for fdc
>
>
> Dear Elke,
>
> here are some of the answers to your questions:
> Single photons were generated from the center of the target
> uniformly in polar angle and azimuth seen by the FCAL (0 < theta < 12 deg).
> The grid for photon energies was from 50 MeV to 5 GeV in 100 MeV steps.
>
> Plots of single photon reconstructio nefficiency that I put at
>
> http://dustbunny.physics.indiana.edu/~mikornic/GlueX/fcal/NewFDCdesign/
>
> are for photons that did not convert before the FCAL and produced a
> single cluster. Translated to cuts: one cluster reconstructed and one
> TrueShower registered in the FCAL. In terms of conversion probability,
> they are not exactly the inverse of the function shown in Fig. 9 of
> CD2-software document, GlueX-doc-806-v7.
>
> Thus:
> > did you simulate for a point like target or for an extended one
> that was a particle gun with the vertex at (0, 0, 65) cm.
>
> > did you place a cut that the conversion of the photon did really happen in
> > the z-range of the FDC
> There are no cuts other than on multiplicity of particles in the FCAL.
> I do not have information regarding the point of conversion.
> I can estimate whether a conversion has taken place before the FCAL
> only from particles that end-up in the FCAL.
>
> >
> > has the material of the cdc end-plate also been changed
> I assume so, but I am not competent to answer.
>
> >
> > do you understand this sharp edge in the photon reconstruction
> > efficiency around 5 degree
> >
> > do you have any idea why reducing the radiation length piratically
> > everywhere by a factor of 2 has so little influence.
> No
>
> > Suggestions:
> >
> > would it be possible to have a 2 dimensional plot showing photons
> > converting vs z and r (=radial distance from the beamline)
> as I said, this requires special MC simulation to track all the particles
> from their origin in the detector.
>
> >
> > it would be helpful to have this plots for fixed position along the
> > beamline.
> I can move the vertex along the z-axis and see if there is an effect.
>
> I will be glad to answer any other question you might have if I can.
>
> Regards,
> Mihajlo
>
> Quoting Elke-Caroline Aschenauer <elke@jlab.org>:
>
> >
> > Dear Mihajlo,
> >
> > I have seen by accident some new plots from you studying the impact of the
> > fdc material on the photon reconstruction in the fcal.
> >
> > First of al thanks a lot for doing these studies. I apologize in advance
> > if I ask questions which other people have already asked or you have
> > explained in your accompanying email, but I have only seen the plots.
> >
> > I was pretty surprised that the overall improvement is not bigger, to
> > understand this better I have some suggestions what to plot and some
> > questions.
> >
> > Questions:
> >
> > did you simulate for a point like target or for an extended one
> >
> > what was the photon energy you simulated
> >
> > did you place a cut that the conversion of the photon did really happen in
> > the z-range of the FDC
> >
> > has the material of the cdc end-plate also been changed
> >
> > do you understand this sharp edge in the photon reconstruction
> > efficiency around 5 degree
> >
> > do you have any idea why reducing the radiation length piratically
> > everywhere by a factor of 2 has so little influence.
> >
> > Suggestions:
> >
> > would it be possible to have a 2 dimensional plot showing photons
> > converting vs z and r (=radial distance from the beamline)
> >
> > it would be helpful to have this plots for fixed position along the
> > beamline.
> >
> > I apologize for so many questions, but the plots are really important and
> > on the first look not so easy to understand.
> >
> > Have a nice evening
> > elke
> >
> >
> >
> >
> >
> >
> > ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
> >  )    `\                                                  -
> > /    '. |                                                  +
> > |       `,              Elke-Caroline Aschenauer            =
> >  \,_  `-/                                                    -
> >  ,&&&&&V         Jefferson Lab                                +
> > ,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
> > ,&&&&&&&&&&;      Mailstop: 12H5          Hampton, VA 23664      -
> > |  |&&&&&&&;\     12000 Jefferson Ave                             +
> > |  |       :_) _  Newport News, VA 23606  Tel.:  001-757-224-1216  =
> > |  |       ;--' | Mail:  elke@jlab.org    Mobil: 001-757-256-5224   -
> > '--'   `-.--.   |                                                    +
> >   \_    |  |---' Tel.:  001-757-269-5352                             =
> >     `-._\__/     Fax.:  001-757-269-6248                              -
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> >
>
>

 ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
  )    `\                                                  -
 /    '. |                                                  +
 |       `,              Elke-Caroline Aschenauer            =
  \,_  `-/                                                    -
  ,&&&&&V         Jefferson Lab                                +
 ,&&&&&&&&:       HALL-D 12C / F381       121-A Atlantic Avenue =
,&&&&&&&&&&;      Mailstop: 12H5          Hampton, VA 23664      -
|  |&&&&&&&;\     12000 Jefferson Ave                             +
|  |       :_) _  Newport News, VA 23606  Tel.:  001-757-224-1216  =
|  |       ;--' | Mail:  elke@jlab.org    Mobil: 001-757-256-5224   -
'--'   `-.--.   |                                                    +
   \_    |  |---' Tel.:  001-757-269-5352                             =
     `-._\__/     Fax.:  001-757-269-6248                              -
            +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+