[d2n-analysis-talk] inelastic events and misc. events in BigBite

[Brad Sawatzky]

On Sun, 23 Oct 2011, posik at jlab.org wrote:

[ . . . ]
> I then computed the ratio of inelastic to misc events for 4 runs, and then
> computed the weighted ratio over the 4 runs. I ended up with the ratio of
> 
> inelastic/misc events =  3.932 +/- 0.065 %
> 
> Finally, I also took a look at how the misc. events compare to the
> inelastic events in the BigBite Cerenkov ADCs. This can be seen in the
> plot Neg_Ration_CerADC.pdf, where I plotted the inelastic events in red
> and misc events in blue for several ADCs. On the left are ADCs
> 4(top),5(middle) and 6(bottom). On the right are ADCs 14(top), 15(middle)
> and 16(bottom). Looking at the Cerenkov ADCs, we can see that the misc
> events fall right around the mean value of the inelastic events.

When I look at the CerADC plots I see the ratio of 
  "inelastic w/ cherenkov signal" : "misc events w/ cherenkov signal"
seems to be 40:1 vs. the 3.9:1 ratio seen in the shower.

Is there a missing prescale factor or something, or does that tell us
that something like 90% of the misc events are missing signal in the
Cherenkov ADC?  You mention that production cuts are in place for these
plots (with the noted exceptions).  I presume the Cherenkov ADC/TDC cuts
must also be disabled since I don't see evidence of the cut in the Cer
ADC spectra?  (Or is the cherenkov _sum_ still always over 400ch and
these plots are just showing ~1 pe backgrounds?)

-- Brad

-- 
Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
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  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov