Re: Updated specifications document GlueX-doc-795

[Elton Smith <elton@jlab.org>]

Hi Matt,

This is a reasonable approach. I also added a note under thresholds
indicating that software thresholds in each cell are also important in the
reconstruction (especially for cells surrounding the core), which is a
point you have made and should not be forgotten.

Thanks, Elton.




Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625

On Tue, 30 Oct 2007, Matthew Shepherd wrote:

>
> 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
> >
> >
>
>