[d2n-analysis-talk] BB cer and sh H2 elastic events

[posik at jlab.org]

Hi all,

  In todays meeting, Brad had asked me to send an email with the plots of
the elastic coin electrons in the BigBite shower and Cerenkov. Thse can
be seen in the file proton_cer_sh.png. The upper plot is the shower x vs
the shower y, and for those events I used a proton cut which was used to
select coin protons in the LHRS(see H2_sum.pdf under the April 29 2010
meeting for proton cut definition) as well as a BB target z-vertex cut
and a BB one track cut. This same cut was then applied to the BB cer
TDCs (the bottom plot in proton_cer_sh.png).

  I also plotted the BB cer ADCs of the coin electrons with the proton +
BB one track a-vertex+mirror cuts (proton_adc_log.png) From looking at
the TDCs of the BB cer one would expect pmts 3,4, and 5 to have a fairly
strong ADC signal like pmts 13,14 and 15 see. However this is not the
case, the ADC amplitudes in pmts 3,4 and 5 are very small. I think this
is due to a hardware issue with the ADCs during this period. During the
experiment Yi noticed this problem, his Halog post can be found here:

http://www.jlab.org/~adaq/halog/html/0902_archive/090222135910.html

The ADC issue is discussed in the last two paragraphs.

-Matt
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