[d2n-analysis-talk] Spike at E/p=0 [SOLVED, but begs a new question]

[David Flay]

On Wed, Dec 15, 2010 at 4:29 PM, Brad Sawatzky <brads at jlab.org> wrote:

> On Tue, 14 Dec 2010, David Flay wrote:
>
> > So therefore, in the future as we look at E/p one <should> include
> > such cuts.
> >
> > Would it make more sense to just include these cuts on E/p in the cut
> > definition file for the replay?
>
> Please verify that the raw ADC information is zero for these bad events.
> By raw, I mean the non-corrected data containing the raw bin value
> returned by the 1881 hardware.
>

Attached you'll find an *.eps file containing plots of a typical ADC
spectrum (block index #7 of PRL1 and PRL2)  with various cuts (explained in
the title of the graph).  We can see that the majority of events that had a
bad momentum (p = kBig) are accounted for here (when E/p ~ 0).


> I would recommend not placing a hard cut (ie. in the cdef file) on
> "high-level" derived variables like this.  There's too great a risk of
> hiding some underlying bug/problem/weirdness.
>

True, that makes sense


>
> For example, at first glance, that looks like quite a few hits that have
> generated a trigger (ie. good hit in two scintillator planes), have a
> good track (correct? if not, p should be undefined), and yet don't
> deposit anything in either lead-glass layer.  That's kind of strange...
>
> Are the usual EDTM and trigger cuts (ie. no T8 pulser, etc) in place for
> these plots?
>

I forgot them in those previous plots, but they are applied to all histos in
this file.

-- 
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David Flay
Physics Department
Temple University
Philadelphia, PA 19122

office: Barton Hall, BA319
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e-mail: flay at jlab.org
           flay at temple.edu

website: http://www.jlab.org/~flay <http://www.jlab.org/%7Eflay>
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