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

[Brad Sawatzky]

That looks better.  Good!

-- Brad


On Tue, 09 Feb 2010, MATTHEW R POSIK wrote:

> Ok found where I went wrong. Since the peds changed I am using a variable
> from my older replays which plot the ADC without ped subtraction but applies
> the gain correction factor. So in order for me to make the photoelectron
> plots, I have to subtract the ped with this gain correction factor
> multiplying it. Since I have to check all the peds, and needed just these
> two plots for the APS I did the ped*gain_correction_factor directly in my
> script. Turns out I used the wrong gain coeficent, using the correct one
> fixes it all (see below)
> 
> 
> 
> On Tue, Feb 9, 2010 at 8:38 PM, MATTHEW R POSIK <tua88437 at temple.edu> wrote:
> 
> > 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
> >
> >
> 
> 
-- 
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