Maria Grazia Pia Systematic validation of Geant4 electromagnetic and hadronic models against proton data Systematic validation of Geant4 electromagnetic and hadronic models against proton data G.A.P. Cirrone 1, G. Cuttone 1, F. Di Rosa 1, S. Guatelli 1, A. Heikkinen 3, B. Mascialino 2, M.G. Pia 1, G. Russo 2 1 INFN Laboratori Nazionali del Sud, Italy 2 INFN Genova, Italy 3 Helsinki Institute of Physics, Finland CHEP 2006 Mumbai, 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 precision –document their precision against established experimental data systematically –evaluate all available Geant4 physics models systematically –publication-quality –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

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 data IEEE Trans. Nucl. Sci., Vol. 52, Issue 4, Aug. 2005, pp

Maria Grazia Pia Proton 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 Physics Space Science Astronauts’ radiation protection

Maria Grazia Pia Relevant Geant4 models Standard Low Energy – ICRU 49 Low Energy – Ziegler 1977 Low Energy – Ziegler 1985 Low Energy – Ziegler 2000 New “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 Hadronic Electromagnetic

Maria Grazia Pia Experimental 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 cm 3 Resolution 100  m Markus Chamber

Maria Grazia Pia Geant4 test application GEANT4 simulation Accurate reproduction of the experimental set-up in the simulation quantitative This is the most difficult part to achieve a quantitative Geant4 physics validation Geometrybeam Geometry and beam characteristics must be known in detail and with high precision Geant4 hadrontherapy Advanced Example

Maria Grazia Pia Software configuration Geant4 7.1 Hadrontherapy-V EMLOW 3.0 Low Energy Electromagnetic data CLHEP Production Threshold = mm MaxStep = cm events

Maria Grazia Pia 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

Maria Grazia Pia EM – ICRU 49 N E =149 N G4 =150 Test statistics p KS CVM AD ENTIRE PEAK ExpG4 S T GoF testCVM-AD Preliminary!

Maria Grazia Pia EM - Standard N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia ICRU49 + Precompound Default N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia Bragg- ICRU49 + Bertini model N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia Bragg – ICRU49 – Binary Cascade N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia Geant4 Parameterised (à la GHEISHA) N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia ICRU49 + default evaporation + Fermi break-up N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia ICRU49 + precompound + GEM evaporation N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia ICRU49 + precompound + GEM evaporation + Fermi break up N E =149 N G4 =150 Test statistics p KS CVM AD Preliminary!

Maria Grazia Pia 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

Maria Grazia Pia 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.

Maria Grazia Pia IEEE Transactions on Nuclear Science 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: 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: