Transcript Systematic validation of Geant4 electromagnetic and hadronic models against proton data G.A.P. Cirrone1, G.

Systematic validation of Geant4
electromagnetic and hadronic models
against 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 2006
Mumbai, 13-17 February 2006
Maria Grazia Pia
Geant4 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 precision against established experimental data
– evaluate all available Geant4 physics models systematically
– publication-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
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K. Amako et al.,
Comparison of Geant4 electromagnetic physics models against the NIST reference data
IEEE Trans. Nucl. Sci., Vol. 52, Issue 4, Aug. 2005, pp. 910-918
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
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–
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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
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Proton Bragg peak
Medical Physics
Space Science
Astronauts’ radiation protection
High Energy Physics
LHC Radiation Monitors
Oncological radiotherapy
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
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Relevant Geant4 models
Electromagnetic
Standard
Low Energy – ICRU 49
Low Energy – Ziegler 1977
Low Energy – Ziegler 1985
Low Energy – Ziegler 2000
New “very low energy” models
Hadronic
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
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Experimental data
CATANA hadrontherapy facility in Catania, Italy
– high precision experimental data satisfying rigorous medical physics protocols
– Geant4 Collaboration members
Markus Ionization chamber
Resolution 100 m
2 mm
Sensitive Volume = 0.05 cm3
Markus Chamber
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Geant4 test application
Accurate reproduction of the experimental set-up in the simulation
This is the most difficult part to achieve a quantitative Geant4 physics validation
Geometry and beam characteristics must be known in detail and with high precision
GEANT4 simulation
Geant4 hadrontherapy
Advanced Example
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Software 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 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
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EM – ICRU 49
ENTIRE
PEAK
Exp
G4
S
2.89
3.39
T
3.26
3.46
GoF test
NE=149
NG4=150
CVM-AD
Test
statistics
p
KS
0.0368
0.999944
CVM
0.0131
0.999887
AD
0.0993
0.999974
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Preliminary!
EM - Standard
NE=149
NG4=150
Test
statistics
p
KS
0.1035
0.380591
CVM
0.1356
0.436725
AD
0.7013
0.557752
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Preliminary!
ICRU49 + Precompound Default
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0403
0.999646
CVM
0.0134
0.999865
AD
0.1079
0.999933
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Bragg- ICRU49 + Bertini model
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0420
0.999218
CVM
0.0133
0.999871
AD
0.1120
0.999900
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Bragg – ICRU49 – Binary Cascade
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0420
0.999218
CVM
0.0123
0.999939
AD
0.1096
0.999921
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Geant4 Parameterised (à la GHEISHA)
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0421
0.999189
CVM
0.0214
0.995490
AD
0.1366
0.999455
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ICRU49 + default evaporation + Fermi break-up
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0421
0.999203
CVM
0.0144
0.999734
AD
0.1160
0.999857
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ICRU49 + precompound + GEM evaporation
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0420
0.999218
CVM
0.0137
0.999831
AD
0.1148
0.999871
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ICRU49 + precompound + GEM evaporation + Fermi break up
Preliminary!
NE=149
NG4=150
Test
statistics
p
KS
0.0487
0.993171
CVM
0.0153
0.999561
AD
0.1199
0.999801
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Outlook
Work 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
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Conclusion
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.
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IEEE Transactions on Nuclear Science
http://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 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]
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