[d2n-analysis-talk] BB Cerenkov TDC cut

[MATTHEW R POSIK]

 I have looked a little bit on the Halog and found some stuff refering to
the timing of the T2 and  BB cer TDCs:

   http://www.jlab.org/~adaq/halog/html/0902_archive/090216153021.html

   http://www.jlab.org/~adaq/halog/html/0902_archive/090217053534.html

I checked the DBB.t2[0]:DBB.BBcerT04[0] for my 2063 run and I do see the
same behaviour. So is this just a TDC/T2  walk effect? If so I am assuming
that it needs to be fixed?

Also I have a Cerenkov sum that is built by using the multi-hit TDCs and
mirror cuts, here is a plot of the cerenkov sum adc_mir_sum_2064.ps. It is
for runs 2063,2064 and 2065. So I am now going to go ahead and look at the
shower with various Cerenkov cuts applied to it.  Before applying the
Cerenkov sum cuts I took a look at what the preshower looks like
(ps_2063.png). I was expecting there to be more of a seperation of the pion
peak (0-500 chan) and the electron peak (500 and up chan) I seen this sort
of sepeartion in some of our earlier runs (ps_1385.png), there were some BB
trigger re-timings between these runs.

-matt



On Fri, Mar 12, 2010 at 4:04 PM, Brad Sawatzky <brads at jlab.org> wrote:

> On Fri, 12 Mar 2010, MATTHEW R POSIK wrote:
>
> > Yes the red region is defined by my cut bounds. I looked at the 20
> > TDCs associated with the PMTs and fit the TDC signal with a Gaussian.
> > I then too the width to be 2*sigma for the Gaussian fit. So I have two
> > arrays of length 20 corresponding to the TDC peak and sigma for each
> > PMT. The difference in the TDC cuts is due to how well the fit fits
> > the TDC signal on each PMT.  Some are TDC signals are not as sharp as
> > others. Should I fix them to all have the same width about the TDC
> > peak?
>
> It should be a single fixed cut on all TDCs for now.
>
> I am 99% sure that the hits on the prominent 'shoulder' to the right of
> the peaks are real Cherenkov signals too.  I think we had pretty good
> idea of what was going on there and how to make a correction that would
> put those hits back in the peak...   Can't remeber the details at the
> moment though -- I think it had to do with how the coincidence between
> the Shower and Cerenkov was made.  It might save you some time if you
> look through the halog during the d2n and transversity period.
>
> -- Brad
>
> --
> Brad Sawatzky, PhD <brads at jlab.org>  -<>-  Jefferson Lab / Hall C / C111
>  Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-5235
> 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
WebSites:
Temple:
http://quarks.temple.edu/
d2n:
http://hallaweb.jlab.org/experiment/E06-014/
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