GenIma: program to simulate emulsions

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GenIma program to simulate emulsions

• Introduction
• GEANT GENerate tracks and grains
• IMA makes pictures
• Examples
• Conclusions

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Introduction

• The lack of data for various conditions (
  particle type, angles, energies, fog densities,
  integration times, etc) and a poor statistics
  make difficult the reconstruction programs
  optimization.
• The large feed-back time between beam tests and
  scanning is responsible for these difficulties.
• It was attracting to reproduce emulsions data by
  Monte-Carlo, as for the other detectors, with the
  hope to increase the comprehension of the
  parameters influence, and to permit an
  optimization of the designing of future beam
  tests.

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• PART 1 Particles generation in GEANT (3.2)
• ( IN PROGRESS)
• Problems with Geant to reproduce in the same
  time ? electrons and the good relativistic rise
  for dE/dX
• ( We keep the coodinates of each energy
  deposite Volume 20020044 ?3 (one layer ) )
• To get a density of 30 grains/100? en mean
  for mip, I eliminate randomly points. ( same
  result than to discriminate on energy deposite)

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Pixels filling zone density f(r) in plan i

• focusing angle
• arcsin(N.A/n)

Grain x,y,z
?
Optical axis
r
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• PART 2
• In a separate program
• For each grain x,y,z we calculate
  intercepted surfaces by conical expansions
  backward and upward , isolating zones of pixels
  to fill. The cone aperture is determined by the
  lense parameters
  ? arcsin(N.A/nrefr)
• Pixels are filled with grey in each of the 16
  picture planes grey densities vary with the
  grain-plane distance( 1/d2 et e-d/? ou
  ?longueur dabsorption optique de lemulsion).
• Size of grains is obtained by an appropiate
  smearing
• Field is 200200 ? for 1024 1024 pixels, 16
  planes cone angle is 36 0 (pure Liban cedar
  oil), or 64 0 (air)
• Then add the wanted amount of random fog (6
  grains/ (10 ?)3 ) and expand them also.
• Pictures are written in Fortran (PPM format),
  then converted in JPEG with XView.

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Format PPM

• http//cedric.cnam.fr/gouet/Var/ppm.html
• Example toto.ppm
• P3
• 4 4
• 255
• red green blue
• 0 0 0 16 16 16 32 32 32 48 48 48
• 64 64 64 80 80 80 96 96 96 112 112 112
• 128 128 128 143 143 143 159 159 159 175 175 175
• 191 191 191 207 207 207 223 23 223 239 239 239

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Oil and air (without fog)

• N.Ansin(?) n1. ou 1.52 ? 640 ou
  360

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Electrons tracks 0 to 1 Mev ? 20 0
horizontal, fog 6/1000 ?3

• Jean
  Imad

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation
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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Emulsion simulation

• 16 images

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Find the vertex ! 5 muons emerging from a point
at 17 microns depth
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Next steps

• Improve grain density f(dE/dX) , saturations, ?
  rays
• add the second layer
• Interface with microscope software
• Compare with available data ( ex efff(angle) )
• Version root, C ?
• Documentation
• Album of various backgrounds (compton fog,
  refreshing actions)
• Distorsion simulation
• Lyon inclined geometry?