maria grazia pia systematic validation of geant4 electromagnetic and hadronic models against proton...
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Maria Grazia Pia
Systematic validation of Geant4 Systematic validation of Geant4
electromagnetic and hadronic models electromagnetic and hadronic models against proton dataagainst proton data
G.A.P. Cirrone1, G. Cuttone1, F. Di Rosa1, S. Guatelli1, A. Heikkinen3, B. Mascialino2, M.G. Pia1, G. Russo2
1INFN Laboratori Nazionali del Sud, Italy 2INFN Genova, Italy
3Helsinki Institute of Physics, Finland
CHEP 2006Mumbai, 13-17 February 2006
Maria Grazia Pia
Geant4 physicsGeant4 physics
Wide set of physics processes and models
Versatility of configuration according to use cases
How to best choose the most appropriate model for my simulation?
Provide objective criteria to evaluate Geant4 physics models– document their precisionprecision against established experimental data– evaluate all available Geant4 physics models systematicallysystematically– publication-qualitypublication-quality results, subject to peer-review process
Geant4 Physics Book– validation of basic Geant4 physics quantities (cross sections, final state
distributions etc.)– demonstration of Geant4 validation in some typical use cases
Maria Grazia Pia
Systematic approach– cover ALL available models
Quantitative validation– rigorous statistical methods for the comparison of simulated and experimental
data distributions
Adopt the same method also for hadronic physics validation– address all modelling options– start from the bottom (low energy)– progress towards higher energy based on solid ground of previous assessments– statistical analysis of compatibility with experimental data
Guidance to users based on objective ground– not only “educated-guess” PhysicsLists
K. Amako et al., Comparison of Geant4 electromagnetic physics models against the NIST reference dataIEEE Trans. Nucl. Sci., Vol. 52, Issue 4, Aug. 2005, pp. 910-918
Maria Grazia Pia
Proton Bragg peakProton Bragg peak
Assess lowest energy range of hadronic interactions– pre-equilibrium + nuclear deexcitation
to build further validation tests on solid ground
Results directly relevant to various experimental use cases– see also talk on Simulation for LHC Radiation Background
Oncological radiotherapy
Medical Physics
LHC Radiation Monitors
High Energy PhysicsHigh Energy PhysicsSpace Science
Astronauts’ radiation protection
Maria Grazia Pia
Relevant Geant4 modelsRelevant Geant4 models
StandardLow Energy – ICRU 49Low Energy – Ziegler 1977Low Energy – Ziegler 1985Low Energy – Ziegler 2000New “very low energy” models
Parameterized (à la GHEISHA)
Nuclear Deexcitation– Default evaporation– GEM evaporation– Fermi break-up
Pre-equilibrium– Precompound model– Bertini model
Intra-nuclear cascade– Bertini cascade– Binary cascade
Elastic scattering– Parameterized– Bertini
HadronicElectromagnetic
Maria Grazia Pia
Experimental dataExperimental data
CATANA hadrontherapy facility in Catania, Italy– high precision experimental data satisfying rigorous medical physics protocols– Geant4 Collaboration members
Markus Ionization chamber
2 mm
Sensitive Volume = 0.05 cm3
Resolution 100 m
Markus Chamber
Maria Grazia Pia
Geant4 test applicationGeant4 test application
GEANT4 simulation
Accurate reproduction of the experimental set-up in the simulation
This is the most difficult part to achieve a quantitative quantitative Geant4 physics validation
GeometryGeometry and beambeam characteristics must be known in detail and with high precision
Geant4 hadrontherapy Advanced Example
Maria Grazia Pia
Software configurationSoftware configuration
Geant4 7.1
Hadrontherapy-V07-01-07
EMLOW 3.0 Low Energy Electromagnetic data
CLHEP 1.9.1.2
Production Threshold = 0.001 mm
MaxStep = 0.002 cm
3000000 events
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Preliminary resultsPreliminary results
Work in progress– all the results presented here are PRELIMINARY
Realistic modelling of beam parameters and geometry details under verification and refinement
– will affect the numerical results of the validation– current values presented here are subject to improvement
Statistical analysis with the Statistical Toolkit– see talk in the Core Libraries track
Maria Grazia Pia
EM – ICRU 49EM – ICRU 49
NE=149
NG4=150
Test statistics
p
KS 0.0368 0.999944
CVM 0.0131 0.999887
AD 0.0993 0.999974
ENTIRE
PEAK
Exp G4
S 2.89 3.39
T 3.26 3.46
GoF test CVM-AD
Preliminary!
Maria Grazia Pia
EM - StandardEM - Standard
NE=149
NG4=150
Test statistics
p
KS 0.1035 0.380591
CVM 0.1356 0.436725
AD 0.7013 0.557752
Preliminary!
Maria Grazia Pia
ICRU49 + Precompound ICRU49 + Precompound DefaultDefault
NE=149
NG4=150
Test statistics
p
KS 0.0403 0.999646
CVM 0.0134 0.999865
AD 0.1079 0.999933
Preliminary!
Maria Grazia Pia
Bragg- ICRU49 + Bertini Bragg- ICRU49 + Bertini modelmodel
NE=149
NG4=150
Test statistics
p
KS 0.0420 0.999218
CVM 0.0133 0.999871
AD 0.1120 0.999900
Preliminary!
Maria Grazia Pia
Bragg – ICRU49 – Binary Bragg – ICRU49 – Binary CascadeCascade
NE=149
NG4=150
Test statistics
p
KS 0.0420 0.999218
CVM 0.0123 0.999939
AD 0.1096 0.999921
Preliminary!
Maria Grazia Pia
Geant4 Parameterised Geant4 Parameterised (à la (à la GHEISHA)GHEISHA)
NE=149
NG4=150
Test statistics
p
KS 0.0421 0.999189
CVM 0.0214 0.995490
AD 0.1366 0.999455
Preliminary!
Maria Grazia Pia
ICRU49 + default evaporation + Fermi ICRU49 + default evaporation + Fermi break-upbreak-up
NE=149
NG4=150
Test statistics
p
KS 0.0421 0.999203
CVM 0.0144 0.999734
AD 0.1160 0.999857
Preliminary!
Maria Grazia Pia
ICRU49 + precompound + GEM ICRU49 + precompound + GEM evaporationevaporation
NE=149
NG4=150
Test statistics
p
KS 0.0420 0.999218
CVM 0.0137 0.999831
AD 0.1148 0.999871
Preliminary!
Maria Grazia Pia
ICRU49 + precompound + GEM evaporation + Fermi ICRU49 + precompound + GEM evaporation + Fermi break upbreak up
NE=149
NG4=150
Test statistics
p
KS 0.0487 0.993171
CVM 0.0153 0.999561
AD 0.1199 0.999801
Preliminary!
Maria Grazia Pia
OutlookOutlookWork in progressWork in progress
Precise reproduction of the experimental set-up– beam size, divergence, energy spread– details of the geometry
Other physics models under test– Low Energy Electromagnetic Ziegler parameterisations– Elastic scattering (Parameterised, Bertini)
Refined statistical analysis
Maria Grazia Pia
ConclusionConclusion
A systematic, quantitative validation of ALL Geant4 electromagnetic and hadronic models against high precision experimental measurements in the energy range 100 MeV
Preliminary results available
Document Geant4 simulation accuracy
Provide guidance to users based on objective ground
Part of the Geant4 Physics Book project
To be submitted for publication in IEEE Trans. Nucl. Sci.
Maria Grazia Pia
IEEE Transactions on Nuclear ScienceIEEE Transactions on Nuclear Sciencehttp://ieeexplore.ieee.org/xpl/RecentIssue.jsp?puNumber=23
Prime journal on technology in particle/nuclear physics
Review process reorganized about one year ago Associate Editor dedicated to computing papers
Various papers associated to CHEP 2004 published on IEEE TNS
Papers associated to CHEP 2006 are welcomePapers associated to CHEP 2006 are welcome
Manuscript submission: http://tns-ieee.manuscriptcentral.com/Papers submitted for publication will be subject to the regular review process
Publications on refereed journals are beneficial not only to authors, but to the whole community of computing-oriented physicists
Our “hardware colleagues” have better established publication habits…
Further info: [email protected]