Looking for Wide Clusters Leon Rochester, 7/9/2004

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Looking for Wide ClustersLeon Rochester, 7/9/2004

• A number of events have been found in EM2 MC
  digis that have very wide clusters.
• To check into these, I generated standard 2 GeV
  muons using the muon_pencil_angle source, in the
  standard instrument.
• I set userAlg to stop on events with at least 16
  hits in any plane, and found 4 events in the
  first 300 events.

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Setup is 2 GeV muon_pencil_angle stop if there
are more than 16 hits in a plane. First event
found is 39
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Magnify
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And a bit more
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Next event found, 105
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Magnify
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A bit more
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Next event, 265(Ive turned off recon, to make
things a bit clearer.)
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Magnify again
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And a bit more, again
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Last one, beginning to get the idea?
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Sigh magnify
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And a bit more31 strips this time!
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Conclusions

• Wide clusters come from delta rays, which are
  faithfully translated into hit strips.
• Wide clusters tend not to be on tracks.
• For the flight instrument, using 2-GeV muons, we
  find wide clusters in about 1 of the events.
• Weve wondered for some time if there arent too
  many delta rays and showers in the CAL for these
  muons.
• Is there some way to do a simple check in Geant4?