Re: bcal lightguides

[Alexander Somov <somov@jlab.org>]

Hi Mihajlo,

Thanks a lot, the plot looks good.
I got a little larger efficiency in the BCAL for
  1 GeV photon (probably because of loser requirements 
on the energy and angular match with the thrown tracks,
but it's Ok). I put the plot to:

http://www.jlab.org/~somov/eff_1gev_gam.pdf
(circles here stand for the efficiency with the light guides,
boxes correspond to the 'default short' SiPm light guides).

I am going to finish with the acceptance studies by the meeting
tomorrow; we can discuss what else will be needed.

Cheers,
        Alex



On Wed, 1 Jul 2009, Kornicer, Mihajlo wrote:

>
> Hi Alex,
>
> please find a link to the photon-efficiency plot
>
> http://www.jlab.org/Hall-D/software/wiki/images/b/bb/PhotonEfficiency_Jun09.pdf
>
> with comparison of current and new geometry with light guides (comparison was 
> done for regular read out, not 3x3). The plot was made for 1.0 GeV photons, 
> if reconstructed with polar angle within 0.05 degree of generated photon and 
> with energy less than 3sigma from generated energy. Sigma is detector 
> dependent resolution.
>
> Let me know if this looks OK and if you need anything else.
>
> Cheers,
> Mihajlo
>
>
> Quoting Alexander Somov <somov@jlab.org>:
>
>> 
>> Hi,
>> 
>> I put geometry files with light guides in the downstream
>> end of the bcal corresponding to  the fine-mesh pmt readout to
>> http://www.jlab.org/~somov/bcal_lightguides/
>> 
>> The light guides in these files are simply modeled as the three plexiglas
>> polycon volumes. That is probably good enough to study the effects of
>> material...
>> 
>> Cheers,
>>        Sascha
>> 
>> 
>> P.S. I also have a bit better description of the light guide geometry
>> where each light guide is modeled as a set of rectangles. This geo was
>> used to study em bg (propagating optical photons in light guides in geant)
>> We can discuss it during the meeting tmorrow
>> 
>> 
>
>
>
>