[BLAST_SHIFTS] Evening "shift" 12-10-02

From: Peter Karpius (karpiusp@einstein.unh.edu)
Date: Wed Dec 11 2002 - 00:21:09 EST


No beam tonight.

I spoke with Genya early on in the shift and he showed me some tdc offset
analysis he had done by hand. Genya's method is similar to mine in that
it still requires median values of sum and position histograms. It
however, does not require the length of the TOF in channels. I think
(Genya please correct me if I am wrong) the requirement of this length
factor is circumvented by specifying not only a central position target
(of zero - which my codes also does) but additonally specifying a target
sum channel (in this case I picked 2000 as it is in the middle of the tdc
range) This may reduce errors by alleviating the req for getting a median
of the diff histogram.

I have been using two macros to run this algorithm. One cuts all paddles
on the opposite paddle 6 as this paddle can have coincs with all others.
>From the ttl:ttr plot, as Genya explained, we can easily cut on 6 for only
those events where the retiming signal provided the trigger.

The second macro is the one I spoke about at the analysis meeting which
cuts on paddle combos with the highest statistics for backward angle
protons. (I am using this just as a comparison)

Almost ready to show some results but I am confused by one thing (forgive
me if someone has said this before)
from eep:
I have taken ptl = (top - bot)/2 and ttl = (top + bot)/2
is this correct?

In TBLCut_coda.h it looks like the pos definition is missing a 0.5 out
front thus making it a diff and not distance from center.

                                                Pete
----------------------------------------------
Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1220
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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