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

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

Quantitative validation 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 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

Proton Bragg peak Medical Physics High Energy Physics Space Science Oncological radiotherapy Medical Physics LHC Radiation Monitors High Energy Physics Space Science Astronauts’ radiation protection 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

Relevant Geant4 models Hadronic Electromagnetic 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 Standard Low Energy – ICRU 49 Low Energy – Ziegler 1977 Low Energy – Ziegler 1985 Low Energy – Ziegler 2000 New “very low energy” models

Markus Ionization chamber Experimental data CATANA hadrontherapy facility in Catania, Italy high precision experimental data satisfying rigorous medical physics protocols Geant4 Collaboration members 2 mm Sensitive Volume = 0.05 cm3 Resolution 100 m Markus Chamber Markus Ionization chamber

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

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

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

Preliminary! EM – ICRU 49 ENTIRE PEAK Exp G4 S 2.89 3.39 T 3.26 3.46 GoF test CVM-AD NE=149 NG4=150 Test statistics p KS 0.0368 0.999944 CVM 0.0131 0.999887 AD 0.0993 0.999974

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

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

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

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

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

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

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

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

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

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.

IEEE Transactions on Nuclear Science http://ieeexplore. ieee 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: Maria.Grazia.Pia@cern.ch