Geant4-INFN (Genova-LNS) Team Validation of Geant4 electromagnetic and hadronic models against...

Geant4-INFN (Genova-LNS) Team

Validation of Geant4 electromagnetic Validation of Geant4 electromagnetic and hadronic models against proton dataand hadronic models against proton data

G.A.P. Cirrone1, G. Cuttone1,

F. Di Rosa1, S. Guatelli1,

B. Mascialino2, M.G. Pia1, G. Russo2

1INFN LNS, Catania, Italy2INFN Genova, Italy

IEEE Nuclear Science SymposiumSan Diego, 30 October – 4 November 2006


Geant4 ToolkitGeant4 Toolkit

Provide objective criteriaobjective criteria to evaluate Geant4 physics models

– Document their precisionprecision against experimental data– Test allall Geant4 physics models systematicallysystematically– Quantitative Quantitative tests with rigorous statistical methods statistical methods

Wide set of physics processes and models

Versatility of configuration according to use cases

How to choose

the most appropriate modelmost appropriate model

for my simulation?


Adopt the same method also for hadronic physics validation– address all modeling options– start from the bottom (low energy)– progress towards higher energy based on previous sound

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

Statistical ToolkitStatistical ToolkitGoodness-of-Fit test

Quantitatitative comparisonof experimental - simulated distributions


Proton Bragg peakProton Bragg peakCompare various Geant4 electromagnetic modelsAssess lowest energy range of hadronic interactions– elastic scattering– pre-equilibrium + nuclear deexcitation

to build further validation tests on solid ground

Results directly relevant to various experimental use cases

Oncological radiotherapy

Medical Physics

LHC Radiation Monitors

High Energy PhysicsHigh Energy PhysicsSpace Science

Astronauts’ radiation protection


Relevant Geant4 physics modelsRelevant Geant4 physics 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

Elastic scattering– Parameterized models– Bertini

Intra-nuclear cascade– Bertini cascade– Binary cascade

HadronicElectromagnetic

Subset of results shown here

Full set of results in publication coming shortly


Experimental dataExperimental data

CATANA hadrontherapy facility in Catania, Italy– high precision experimental data satisfying rigorous medical physics protocols– Geant4 Collaboration members

Validation measurementsMarkus Ionization chamber

2 mm

Sensitive Volume = 0.05 cm3

Resolution 100 m

Markus Chamber


Geant4 simulationGeant4 simulationAccurate reproduction of the experimental set-up

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

Ad hoc beam line set-up for Geant4 validation

to enhance peculiar effects of physics processes

Eproton = 63.5 MeVE = 300 keV


Electromagnetic processesElectromagnetic processes

Electromagnetic options

Standard EM

Low Energy EM – ICRU 49

Low Energy EM – Ziegler 1977 Low Energy EM – Ziegler 1985 Low Energy EM – Ziegler 2000


Electromagnetic processesElectromagnetic processesStandard EM: p, ions, , e- e+

p-valuep-value

CvM KS AD

Left branch 0.418

Right branch 0.736

Whole curve 0.438

CvM Cramer-von Mises testKS Kolmogorov-Smirnov testAD Anderson-Darling test

1 M events

mm

Geant4Experimental data

Standard EM


Electromagnetic processes Electromagnetic processes

Low Energy EM – ICRU49: p, ions

Low Energy EM – Livermore: , e-

Standard EM : e+

p-valuep-value

CvM KS AD

Left branch 0.530

Right branch 0.985

Whole curve 0.676


1 M events

mm


LowE EM – ICRU49


Electromagnetic processesElectromagnetic processesLow Energy EM – Ziegler 1977: p, ions


Standard EM : e+

1 M events

mm


p-valuep-value

CvM KS AD

Left branch 0.420

Right branch 0.985

Whole curve 0.547

LowE EM – Ziegler 1977



Electromagnetic processesElectromagnetic processes


Low Energy EM – Ziegler 1985: p, ions


Standard EM : e+

Subject to further investigation1 M events

mm



Electromagnetic processesElectromagnetic processesLow Energy EM – Ziegler 2000: p, ions


Standard EM : e+

Subject to further investigation1 M events

mm




Electromagnetic processes Electromagnetic processes

SummarySummary

p-valuep-value

LowE

ICRU49LowE Ziegler

1977Standard

Left branch (CvM) 0.530 0.420 0.418

Right branch (KS) 0.985 0.985 0.736

Whole curve (AD) 0.676 0.547 0.438


Best EM option: LowE – ICRU49LowE – ICRU49Selected for further EM + Hadronic tests


Electromagnetic processes Electromagnetic processes ++

Elastic scatteringElastic scattering

Elastic scattering options

HadronElastic process with LElastic model

HadronElastic process with BertiniElastic model

UHadronElastic process with HadronElastic model


EM + Elastic scatteringEM + Elastic scattering



Standard EM : e+

HadronElastic with LElasticLElasticp-valuep-value

CvM KS AD

Left branch 0.522

Right branch 0.985

Whole curve 0.697

LowE EM – ICRU49

LElastic


1 M events

mm



EM + Elastic scatteringEM + Elastic scattering



Standard EM : e+

UHadronElastic with HadronElasticHadronElasticp-valuep-value

CvM KS AD

Left branch 0.490

Right branch 0.735

Whole curve 0.669

LowE EM – ICRU49

HadronElastic


0.5 M events

mm



Electromagnetic processes Electromagnetic processes ++

Elastic scatteringElastic scattering++

Hadronic inelastic scatteringHadronic inelastic scattering

Hadronic Inelastic options

Precompound with Default Evaporation Precompound with GEM Evaporation Precompound with Default Evaporation + Fermi Break-up

Bertini


EM + hadronic physicsEM + hadronic physicsLow Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+HadronElastic with LElasticLElasticPrecompound Precompound with Default Evaporation Default Evaporation

p-valuep-value

CvM KS AD

Left branch 0.836

Right branch 0.985

Whole curve 0.946

LowE EM – ICRU49

LElastic


1 M events

mm


Precompound default


EM + hadronic physicsEM + hadronic physics

Standard EM: p, ions, , e- e+

HadronElastic with LElasticLElasticPrecompound Precompound with Default Evaporation Default Evaporation

p-valuep-value

CvM KS AD

Left branch 0.648

Right branch 0.760

Whole curve 0.666


1 M events

mm


Standard EM

LElastic

Precompound default


EM + hadronic physicsEM + hadronic physicsLow Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+UHadronElastic with HadronElastic HadronElastic Precompound Precompound with Default Evaporation Default Evaporation

p-valuep-value

CvM KS AD

Left branch 0.973

Right branch 0.985

Whole curve 0.982

LowE EM – ICRU49

HadronElastic


0.5 M events

mm


Precompound default


EM + hadronic physicsEM + hadronic physicsLow Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+HadronElastic with LElasticLElasticPrecompound Precompound with GEM Evaporation GEM Evaporation

p-valuep-value

CvM KS AD

Left branch 0.667

Right branch 0.985

Whole curve 0.858

LowE EM – ICRU49

LElastic


0.5 M events

mm


Precompound with GEM Evaporation


EM + hadronic physicsEM + hadronic physicsLow Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+HadronElastic with LElasticLElasticPrecompound Precompound with Fermi Break-up Fermi Break-up

p-valuep-value

CvM KS AD

Left branch 0.814

Right branch 0.985

Whole curve 0.945

LowE EM – ICRU49

LElastic


0.5 M events

mm


Precompound with Fermi Break-up



Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+HadronElastic with LElasticLElasticBertini InelasticBertini Inelastic

p-valuep-value

CvM KS AD

Left branch 0.790

Right branch 0.985

Whole curve 0.936

LowE EM – ICRU49

LElastic


1 M events

mm


Bertini Inelastic



Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e-Standard EM : e+HadronElastic with BertiniElasticBertini InelasticBertini Inelastic

p-valuep-value

CvM KS AD

Left branch 0.977

Right branch 0.985

Whole curve 0.994

LowE EM – ICRU49

BertiniElastic


0.5 M events

mm


Bertini Inelastic


Electromagnetic + Hadronic Electromagnetic + Hadronic

SummarySummary

p-valuep-valueStandard LElastic

Precompound

LowE ICRU49

LElastic

Precompound

GEM

LowE ICRU49

LElastic

Bertini Inelastic

LowE ICRU49

LElastic

Precompound

Fermi Break-up

LowE ICRU49

LElastic

Precompound

LowE ICRU49

HadronElastic

Precompound

LowE ICRU49

Bertini Elastic

Bertini Inelastic

Left branch (CvM)

0.648 0.667 0.790 0.814 0.836 0.973 0.977

Right branch

(KS)0.760 0.985 0.985 0.985 0.985 0.985 0.985

Whole curve

(AD)0.666 0.858 0.936 0.945 0.946 0.982 0.994

Key ingredientsKey ingredients Precise electromagnetic electromagnetic physics Good elastic scatteringelastic scattering model Good pre-equilibriumpre-equilibrium model


ConclusionConclusion

Publication coming soon with complete results

Selection of Geant4 physics models(aka PhysicsList)

based on quantitative experimental validation, rather than just “educated guess”

...2-year project to get there

SystematicSystematic, quantitativequantitative validation of all all Geant4 electromagnetic and hadronic models

in the energy range < 100 MeVagainst high precision experimental data

Document Geant4 simulation accuracyDocument Geant4 simulation accuracyProvide guidance for Geant4 use based on objective ground

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