[d2n-analysis-talk] Positive Polarity GC/PR Calibration

[David Flay]

Hi Brad,

I wanted to finish off the GC/PR calibration, since I have only two
kinematics to go -- p = 1.12 GeV (4-pass) and p = 1.34 GeV (5-pass).

The gas Cherenkov calibration went just fine -- the calibration done for
negative polarity works on these positive polarity ones (the 1
photoelectron peak shows up at 200 channels).  I have attached a Cherenkov
sum plot for the p = 1.12 GeV kinematic.  It is odd how there is <no> main
peak in this histogram -- the same is true for the p = 1.34 GeV case...

I was expecting something similar to happen on the pion rejector. 
However, when examining the ADCs (corrected variables) for the p = 1.12
GeV kinematic, I have <two> peaks (even with a cut requiring GC_sum==0),
one being at ~45, and the other at 100.  I was anticipating that the
\pi^{+} would fall in one peak, at around 100.  Now, I have chained runs
together to get decent statistics, but I don't think that's the issue
here, as this also occurs for individual runs.  This effect is most
visible in the second layer.  The same thing happens for p = 1.34 GeV.

I'm curious as to what that double-peak structure is -- it can't be e^{+}
since I have a L.cer.asum_c==0 cut on these plots...

I've also checked to make sure that the 'L.prl1.a_p[]' variable is
properly subtracting the pedestal, etc. and it's doing its job.


Dave

-------------------------------------------------
David Flay
Physics Department
Temple University
Philadelphia, PA 19122

office: Barton Hall, BA319
phone: (215) 204-1331

e-mail: flay at jlab.org
            flay at temple.edu

website: http://www.jlab.org/~flay
              http://quarks.temple.edu
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