dEdX separation at low energy: status

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dE/dX ?-? separation at low energy status
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No muon in spectrometer?

• Find muon in target (stopping or side exiting)
• If not identified by TT ( see Darios muon
  identification notes)
• Can we separate it from interacting pions?
• This concerns typically lt 1 GeV/c muons
• In the last 56 foils, the dE/dX of the muon will
  be higher than an interacting pion one

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Low energy identification

• WishRecognize muon from pions when both stop in
  target
• NeedGenerate the stopping of muons in 1 or 2
  bricks
• and  stopped  pions ( really stopped, or lost
  by interaction)
• NeedOptimize the dE/dX response of a single
  emulsion
• Compare the mean dE/dX ( grain numbers) of the
  30-56 last emulsions (optimization not yet
  finished)

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Stopping muon 175 MeV/c
Stopping or interacting pion
Brique i1
Brique i
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dE/dX ?/? (270/301 MeV/c) both stopping at
564298
The most difficult situation !
Emulsion number ( 2 bricks)
6
?- et ? 202 MeV/c
7
? et ?- 175MeV/c
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• Simulation of a whole brick with the fast Genima
  version 100 stopping muons or pions ( 5 hours
  cp)
• Study of one emulsion dE/dX response for
  different incoming muon energies (??) and 2
  tomographic densities (16 and 44 frames/layer)
• Genima oil objective N.A0.8 no background
• angular cut tg ?lt1.
• one track/event, no track
  reconstruction
• dE/dX average number of
  grains found along the N emulsions
  track in 40 emulsions
• Saturations finite grey level number (256) and
  mixing by depth of field effects. Grey level has
  been adjusted to minimize the saturation effects,
  leadind to a value not compatible with a correct
  MIP efficiency this implies a second turn of
  microscope scan devoted to dE/dX measurement

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dE/dX properties of a single emulsion

• Grey level and cluster definition thresholds to
  minimize saturations effects
• 7 muon energies 30, 50, 70, 80 100, 150, 250
  MeV, ?0 tracks
• plot( Ncluster found/Ngeant). If constante no
  distorsion to dE/dX curve brought by saturations.

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• R N cluster found / N geant
  hits
• Energy (MeV) R rms rms/R
  dE/dX th (MeV/gr)
• 30 0.4 0.065
  16.3 9.7
• 50 0.75 0.1
  13.4 5.25
• 70 0.95 0.11
  11.4 3.5
• 80 0.996 0.11
  11.7 3.1
• 100 1.02 0.115
  11.8 2.5
• 150 1. 0.125
  12.5 2.02
• 250 0.95 0.15
  15.5 1.8

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Single emulsion ( 80 MeV muon)found clusters
44 views 18.
16 views 19.3
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Single emulsion ( 80 MeV muon)found clusters /
geant hits
44 views 11.7
16 views 13.5
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175 MeV/c muon
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Use of emulsions informations

• Find the last hit N of the track
• Average the dE/dX for the emulsions number 1 to
  N-4 ( values from the preceeding brick can be
  used to increase the accuracy)
• Make cuts on this value

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RANGE
202 MeV/c
175 MeV/c
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dE/dX
? 202 MeV/c
? 175 MeV/c
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56 measures
? 1000 MeV/c
? 175 MeV/c
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Pion identification for 2 ??
??
pion momentum (MeV/c)
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Mu identification (95 ??)
??
pion momentum (MeV/c)
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Conclusions (preliminary)

• In using devoted optimised re-scanning runs for
  which the mip efficiency is not maximum (but the
  track is already identified and measured
• Then the number of found grains in the 30-40
  last emulsions permits a good separation of
  muons/pions
• for momenta greater than 300 MeV/c.
• Using 44 frames instead 16 slightly improves de
  dE/dX
• resolution
• Next more stat, noise, 2 bricks