[d2n-analysis-talk] APS talk (Cerenkov pedestals)

[MATTHEW R POSIK]

Checked up on what you had asked and here is the plot of the electron signal
(red histo) and the background(blue histo). The background peak is at chan
510, which is consistent with my ped runs I did. I'll recheck my plot, maybe
I subtracted the wrong ped or using the wrong gain constant.

On Tue, Feb 9, 2010 at 4:37 PM, Brad Sawatzky <brads at jlab.org> wrote:

> On Tue, 09 Feb 2010, MATTHEW R POSIK wrote:
>
> [ . . . ]
> > For the red histo I then apply a TDC and mirror cut that apply to
> > mirror 13.  Where as for the blue histo I apply to mirror 13(ie. ADC
> > 13 ) a cut on the TDC and mirror associated with mirror 17.
> >
> > But if I replay the first 100,000 with a T8 cut
> > ("DBB.evtypebits&1<<8)==1<<8") the peds I get for both sides are below
> > (1849_beam.png and 1849_rhrs.png) for the beam line and rhrs sides.
>
> The center of the pedestal for Mirror 3 from the T8 cut is consistent
> with the rough centroid of the blue background shown in
> aps_mir3_no_cor.png.  That makes sense.
>
> > Since when I make that "background" cut (blue histo) on mirror 13 and
> > have a non zero centered peak, does that mean there is some
> > correlation between mirror 13 and 17?
>
> I'd double check that the pedestal you're subtracting is really the one
> you're showing in 1849_rhrs.png -- I'll bet it isn't.  (I should be able
> to see the pedestal start to rise up in the lowest bins of your mirror13
> ped-subracted plot in your talk, but there's nothing there.)
>
> That is, make the same kind of non-ped-subtracted plot for mirror 13 as
> you did for aps_mir3_no_cor.png.  If there really is a pedestal below
> the blue peak, we should see it.
>
> -- Brad
>
> --
> Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
>  Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-7848
> The most exciting phrase to hear in science, the one that heralds new
>  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov
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-- 
Matthew Posik
Email: posik at temple.edu
Temple University Physics Dept.
Office: BA-319
Office #:  215-204-1331
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