Re: UPV region - photon detection (fwd)

[Elton Smith <elton@jlab.org>]

---------- Forwarded message ----------
Date: Tue, 16 Oct 2007 10:25:39 -0400
From: Matthew Shepherd <mashephe@indiana.edu>
To: Elton Smith <elton@jlab.org>
Cc: Alex Dzierba <dzierba@indiana.edu>, Paul Eugenio <eugenio@fsu.edu>,
     George.Lolos@uregina.ca, Zisis Papandreou <zisis@uregina.ca>,
     Elke Aschenauer <elke@jlab.org>, Curtis Meyer <cmeyer@ernest.phys.cmu.edu>,
     Richard Jones <richard.t.jones@uconn.edu>
Subject: Re: UPV region - photon detection


Hi Elton,

On Oct 16, 2007, at 10:17 AM, Elton Smith wrote:
>> Readout would need some work.  Downstream end readout is tricky
>> because of the taper.
> I agree this would not work.

One could imagine something fancy such as separating lead sheets
between fibers that were also tapered, but I don't know how one would
machine such a thing.  I would be hesitant to completely rule out
downstream readout, but offhand I don't see how to do it practically.

> Upstream end readout creates a gap between the
>> FDC and the wedge that is not so desirable.
>
> I do not understand this comment. The last FDC is likely to be far
> enough
> upstream that there will be enough room between the end of the last
> FDC
> and the end of the bcal for the wedge. But this distance can also be
> optimized.

For photons that convert in that FDC ring it would be desirable to
pick up the e+/e- pair as soon as possible since this enhances the
probability that they will be nicely reconstructed as a single
shower.  I think this is best done when the distance between the
converter (FDC ring) and calorimeter is minimized.

Cheers,

-Matt