[d2n-analysis-talk] Beta distribution

[David Flay]

On Sat, Mar 27, 2010 at 11:36 PM, Brad Sawatzky <brads at jlab.org> wrote:

> There are a number of things that puzzle me about these plots:
>  a) The x-range populated in the Beta vs. x plot is quite different
>    (smaller) than the x-range populated by the s1 and s2m plots.  Why?
>

I double checked my script -- I'm missing some cuts on the S1, S2m vs.
track-x plots.  See attached.
(I have all my 'good event' cuts on beta vs. track-x, and forgot them on S1,
S2m vs. track-x.  The cuts match now.)

 b) S1 is supposed to have 6 paddles, yet there are far more than 6
>    discrete regions showing different structure in the S1 plot.

 c) Judging by the extent of the offset regions in the S1 vs. X plot, I
>    can convince myself that there are at least 14 discrete "blocks"
>    plotted, if I count the little blips at the far edges then I get 16.
>  d) S2m carries the timing for the trigger L1A (which is the common stop
>    for S1).
>  e) Therefore, the variation seen is S1 vs. X is really paddle-to-paddle
>    variation in the _S2m_ paddle offsets.
>

This makes sense to me -- wouldn't that explain why there's so many blips in
S1 time avg. vs track-x?

In which case, I can take a closer look at S2m -- however I don't know how
much my tweaking of those time averages per paddle will do for the beta vs.
track-x plot.  I remember the effect was small, almost non-existent.  I'll
take another shot.

Also -- wouldn't (c) through (e) imply that S2m vs. track-x doesn't
necessarily make any sense, since it carries the timing?  Or, I should say,
doesn't provide any new information?

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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