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Re: PROBLEM REMAINS with gluex-doc-1300




HI Andrei,

Of course the "first layer" for the SiPM option is actually the sum of 3
of your layers in depth. I assume you did this as well?

Elton.



Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625
(757) 269-6331 fax

On Wed, 15 Jul 2009 semenov@jlab.org wrote:

> Elton:
>
> This explanation does not work. The problem is the figures I sent to you
> contain the sum of numbers from the four cells of the 1st layer (viz., the
> maximal signal + all 3 other "not-maximal" signals), and the numbers in
> the spectra I sent to you are MUCH SMALLER than yours. Also, with
> selection of the "maximal" signal, you can not go away from the big
> zero-channel spike: if the sum of four signals is close to zero => the
> maximal signal is close to zero too.
>
> I still think that your figures made using not correct values from the
> ntuples.
>
> Sorry,
> Andrei
>
>
>
> >
> >
> > Hi Andrei,
> >
> > What is plotted is the maximum number (not the sum) in one of the four
> > cells in the first layer. It is to find the channel that has the maximum
> > signal. It may not always be the same segment, but we know that at least
> > one segment has that much energy.
> >
> > Cheers, Elton.
> >
> > Elton Smith
> > Jefferson Lab MS 12H5
> > 12000 Jefferson Ave
> > Suite # 16
> > Newport News, VA 23606
> > elton@jlab.org
> > (757) 269-7625
> > (757) 269-6331 fax
> >
> > On Tue, 14 Jul 2009 semenov@jlab.org wrote:
> >
> >> Elton:
> >>
> >> What did you plot in the figure 9 of the gluex-doc-1300 note?
> >>
> >> The caption says that it's "maximum number of photoelectrons detected in
> >> the first layer". What's that?
> >>
> >> If you meant the sum of photoelectrons in the four cells of the first
> >> layer, the spectra you show looks strange: with your 23 pe/MeV
> >> conversion
> >> factor, the means of your downstream and upstream spectra are 34.25 and
> >> 95.19 (respectively) that is significantly bigger values than we have in
> >> our report for 45 pe/MeV conversion for the sum of four cells of the
> >> first
> >> layer (24.56 and 55.81 respectively, see Figs.27 and 23 of
> >> gluex-doc-1301
> >> or the attachment to this e-mail). Because you used the ntuple that were
> >> produced by Irina, your numbers must be SMALLER than ours by the factor
> >> (23/45).
> >>
> >> Most probably, you used wrong variables from the ntuples. I did not
> >> check
> >> it, but you might have the same problem with your figures 10,11,12 also.
> >>
> >> Another issue is that for photoelectrons you can not just scale the
> >> spectra is you use another MeV-to-pe conversion factor. Irina will
> >> prepare
> >> the correct figures for you tomorrow.
> >>
> >> Sorry,
> >> Andrei
> >>
> >>
> >>
> >>
> >> >
> >> > Dear collaborators,
> >> >
> >> > I have uploaded a new version of the cover document, including a
> >> summary.
> >> > Please send me any feedback by noon JLab time, so I can place final
> >> > documents on the web site for reviewers.
> >> >
> >> > Thanks, Elton.
> >> >
> >> > Elton Smith
> >> > Jefferson Lab MS 12H5
> >> > 12000 Jefferson Ave
> >> > Suite # 16
> >> > Newport News, VA 23606
> >> > elton@jlab.org
> >> > (757) 269-7625
> >> > (757) 269-6331 fax
> >> >
> >>
> >
>
>
>
>