<br><br><div class="gmail_quote">On Sat, Mar 6, 2010 at 4:19 PM, Brad Sawatzky <<a href="mailto:brads@jlab.org">brads@jlab.org</a>> wrote:<br><blockquote class="gmail_quote">
That looks a lot better. I hope I didn't come on too aggressively with<br>
the stuff about beta :-) I know you didn't have time to read or respond<br>
to any of my posts as I wrote them.<br></blockquote><div><br>No problem, I should've known better. <br></div><div> </div><blockquote class="gmail_quote">
Cutting on beta is 'OK', but _only_ because it is convenient. The<br>
actual logic is something like this:<br>
A) S2m < S1 implies that the particle hit the back plane first, then<br>
the front plane,<br>
B) The abs(S2m - S1) is about the same as for particles traveling<br>
with speed c between the two planes,<br>
*C) The only class of particles that can reasonably satisfy A and B<br>
are cosmics illuminating the detector stack from above,<br>
D) We can remove those (declared) cosmic events either by cutting on<br>
S2m < S1 (with some reasonable margin) or, since<br>
1/beta == const * (s2m - s1),<br>
it is equivalent to apply a cut on the derived quantity beta.<br></blockquote><div><br>This makes sense (using D) -- keeps the logic of the cosmics up front <br><br>I'll have a bunch of slides of everything for the talk as well<br>
<br>Also -- I've been looking at the ADCs (for each paddle, so a sum of L & R) and considering GC > 0 (red), and GC == 0 (blue) cuts. I can 'pick out' a peak using GC > 0, but the whole spectrum is unaffected by GC ==0 ... I tried using this result to 'clean up' my 2D PR plot (OR-ing together all these histos, choosing events for < 400 in the scintillators)... doesn't change anything. I attached the *.pdf of the paddle ADCs.<br>
<br>I'm not absolutely certain of this being the right way of doing it... wouldn't that main peak in the ADC of the scintillators be due to electronics, setting some threshold? <br><br></div></div><br clear="all">
<br>-- <br>-----------------------------------------------------------<br>David Flay<br>Physics Department<br>Temple University<br>Philadelphia, PA 19122 <br><br>office: Barton Hall, BA319<br>phone: (215) 204-1331<br><br>
e-mail: <a href="mailto:flay@jlab.org">flay@jlab.org</a> <br> <a href="mailto:flay@temple.edu">flay@temple.edu</a><br><br>website: <a href="http://www.jlab.org/~flay">http://www.jlab.org/~flay</a><br> <a href="http://quarks.temple.edu">http://quarks.temple.edu</a><br>
-----------------------------------------------------------<br><br><br>