Study of a tracking algorithm using Poisson Distribution of grains for microtracks determination

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Study of a tracking algorithm using Poisson
Distribution of grains for microtracks
determination
Meeting of June 2005, the 29th
Damien ROBERT
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OUTLINE
I Principle of lyontracker algorithm II
Description of the program III Primary results
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I Principle of lyontracker algorithm

• Grains impression in emulsions follows a
  Poisson distribution
• We have P0(l)exp(-cl) probability that no event
  occurs over the distance l where c is the events
  cadency (c0.3 grains/µm)
• Probability to have a gap for physical tracks
  through emulsions
• Pgap(N)exp(-cNz) where N is the gap length and
  z the view thickness

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?Processing quite heavy ? very slow (4 times
slower than smart tracker) ?A good way to
decrease the background of micro tracks ?What
about efficiency?
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III Primary Results

• Efficiency Test
• 8 sheets exposed to a pion beam
• Efficiency N8/(N7N8) a first estimation 80

Preliminary
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Conclusion and perspectives
?Good preliminary results for efficiency ?The
purity seems to be better with this algorithm but
systematics are still under study ?Improvment
needed speed