Re: Updated specifications document GlueX-doc-795

[Matthew Shepherd <mashephe@indiana.edu>]

Along these lines, I've been thinking about the BCAL simulation.  I  
originally thought to update the thresholds based on this factor of  
4, but as Elton points out, this can be compensated for by higher PDE  
for green fibers and also lower noise rates.  Rather than shoot at a  
moving target, maybe the best course of action is hold steady until  
UR has some input on cosmic tests with SiPMs.  Once we have this,  
then we should adjust the response in the Monte Carlo if necessary.   
To be of use for the calorimeter review, it would be ideal this input  
on PDE with the green fibers was available by the end of the calendar  
year since we will need to redo the calibration and potentially  
retune the clustering algorithm for the BCAL.

Cheers,

Matt


On Oct 30, 2007, at 3:48 PM, Elton Smith wrote:

>
> Dear George and Zisis,
>
> The lower estimates for the number of photons produced in the Bcal  
> by a
> factor of 4 are reflected in the updated specifications document. I  
> have
> updated the specifications GlueX-doc-795 for the Bcal readout. Both  
> the
> pdf and tar files with all sources have been updated.
>
> The main thrusts of the changes imply a revised requirement for the  
> PDE to
> 21% and a dark count of 27 MHz. These numbers should be looked at
> critically and may in fact be pessimistic if measurements of the green
> calorimeter show more photons than cosmic-ray measurements.
>
> Careful reading and consideration of the document is welcome as it  
> is hot
> off the press.
>
>
> Thanks, Elton.
>
> Elton Smith
> Jefferson Lab MS 12H5
> 12000 Jefferson Ave
> Suite # 16
> Newport News, VA 23606
> elton@jlab.org
> (757) 269-7625
>
>