Geant4 results

1
Part IV

• Geant4 results

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Overview of applications and results

• Geant4 is used in a wide variety of experiments
  and fields
• the future LHC experiments
• neutrino and astroparticle physics experiments
• space science
• astrophysics
• X-ray analysis
• medical physics
• theoretical applications
• ...

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Geometries
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Cuts in range (G3/G4)
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Visible energy in Si vs energy of the incident
electron G3, G4, data
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Multiple scattering in thin layers
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Backscattering
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Low energy e.m. extensions
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High energy muons
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Geant4 hadronic physics
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Hadronic models, parameterised
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Photon evaporation
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Stopping pions
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Neutrons
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Atlas geometry
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CMS geometry and magnetic field
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CMS e.m. calorimeter
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BaBar Geant4-based Simulation

• BaBar Object-oriented Geant4-based Unified
  Simulation (BOGUS)
• Integrated framework for Fast and Full simulation
• Fast simulation available for public use since
  Feb. 99
• complete of fast reconstruction (downstream
  modules)
• validation completed (B0 -gt K pi-, B0 -gt D- l
  nu, B0 -gt J/Psi K0S, )
• Current version based on Geant4.0.1 (additional
  development patches)
• Integrated in BaBar environment
• primary generators, reconstruction, OODB
  persistency (materials geometry description
  parameters, events)
• parameters for materials and geometry shared with
  reconstruction applications

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Examples of BaBar Geant4 geometries
EMC Electro Magnetic Calorimeter
SVT Silicon Vertex Tracker
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Borexino

• Geant4 components used to track photons
• geometry
• physics processes pertinent to optical photons
  (reflection, rifraction, absorption etc.)
• visualisation
• They have developed absorption and reemission
  processes typical of Borexino scintillator

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Borexino
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Medical physics applications

• A very active field!
• Studies for brachytherapy (IST Genova)
• Interface to CT for treatment planning (Novara)
• Feasibility studies for new hadrotherapy
  facilities (TERA)
• Magic Cube (INFN Torino)
• etc...
• Technology transfer from HEP to other fields

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Low Energy processes for medical applications
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Bragg peak
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Space applications
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Theoretical physics applications

• Geant4 is used also by theorists
• Geant4 theoretical models for hadronic physics to
  be used by theorists for further theoretical
  developments and studies (Quantum Molecular
  Dynamics, Heavy Ions models etc.)
• All this is made possible by the OO design of
  Geant4
• modular, flexible, extensible
• the physics is clearly exposed

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Performance

• Geant4 - Geant3.21 comparisons
• Realistic detector configurations
• All results and plots available at
• http//wwwinfo.cern.ch/asd/geant/geant4_public/gal
  lery/EMbenchmarks
• Benchmark in liquid Argon Pb calorimeter
• At a comparable physics performance Geant4 is
  faster than Geant3.21
• by a factor gt3 using exactly the same cuts
• by a factor gt10 when Geant4 cuts are optimized,
  keeping the same physics performance
• At comparable speed, Geant4 physics perfomance is
  far superior to Geant3.21 one
• Benchmark in thin silicon layer
• Single volume, single material
• At a comparable physics performance Geant4 is
  25 faster than Geant3.21
• Many factors contribute to these results design,
  more powerful geometry navigation and tracking
  algorithms, improved physics algorithms etc.
• Note Geant3.21 run in its best optimized
  configuration for these tests

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An ambitious project

• What if the geometry to describe with Geant4 were
  DNA and the process were mutagenesis?
• Study of radiation damage at the cellular and DNA
  level in the space radiation environment
• ESA-sponsored project, in collaboration with INFN
• INFN (Genova, Torino, Cosenza)
• Istituto Nazionale per la Ricerca sul Cancro
• Università del Piemonte Orientale (Novara)
• ESA
• CERN
• Multi-disciplinary Collaboration of
• astrophysicists and space scientists
• particle physicists
• medical physicists
• biologists
• physicians
• First phase of the project User Requirements

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Conclusions

• Geant4 is used in a variety of applications
• HEP and nuclear physics experiments
• astrophysics and astro-particle physics
• space science studies
• medical physics
• etc.
• Several experiments are already in an advanced
  stage of their Geant4-based applications
• complex geometry descriptions
• comparisons with experimental data
• production mode
• Various new tools offered by Geant4 respond to
  essential needs of some user communities
• CAD interface
• extensions of the physics processes covered
• new physics
• standard-compliant tools
• etc.