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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 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 -> K+ pi-, B0 -> D*- l+ nu,

B0 -> 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

BaBar Geant4-based Simulation

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SVTSilicon Vertex Tracker

EMCElectro Magnetic Calorimeter

Examples of BaBar Geant4 geometries

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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/

gallery/EMbenchmarks

Benchmark in liquid Argon + Pb calorimeter At a comparable physics performance Geant4 is faster

than Geant3.21 by a factor >3 using exactly the same cuts by a factor >10 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.