[d2n-analysis-talk] BB cer pion rejection plots

[Brad Sawatzky]

On Tue, 07 Dec 2010, MATTHEW R POSIK wrote:

> I do not understand the large change in the pion rejection from PMT
> 14,16.  I spent a lot of time last night looking into it, but could
> not conclude why. I talked to Dr. Meziani about it and said he needed
> to think about it.  Do you have any ideas? I should also mention that
> pmts 11,12 and 18 had no events left in the pion sample after I
> applied the Cerenkov cut to them.

For next day, it would be good to have some plots of the ADC spectrum
for those PMTs, and for one or two of the 'normal' PMTs.  Perhaps that
will give us some insight.

> The errors that I had on the pion rejection factors were not
> completely correct. Since I am plotting N_p/N_e, where N_p is my
> initial pion sample, and N_e is the number of events left after my
> Cerenkov cut, then my error should be
> 
> (1/N_e)*sqrt(N_p)
> 
> My most recent version of the talk that I just sent out has this plot with
> the errors above on it. The error bars are hidden due to the log scale. But
> the ranged on average from 1-20.

I think the plots in the talk look good.

> For the pion rejection, I used the T6 and the initial pion sample  on the
> small angle side ranged from ~5000-3000 events per mirror, with pmt 8 having
> 400 events. And for the large angle side the initial pion sample ranged from
> 3000-900 events per mirror, with pmt 18 having 200 events.

-- 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
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov