1. Geant4 physics validation: Bragg Peak P. Cirrone, G. Cuttone, F. Di Rosa, S. Guatelli, B. Mascialino, M. G. Pia, G. Russo 4th Workshop on Geant4 Bio-medical Developments, Geant4 Physics ValidationINF Genova, 13-20 July 2005

2. Outline • Brief summary of the Geant4 hadrontherapy application • Bragg peak test: • Validation of Geant4 electromagnetic and hadronic physics models

3. Modulator & Range shifter Ligth field Scattering system Monitor chambers Laser Scope of the hadrontherapy Geant4 application • Model accurately the CATANA hadrontherapy beam line • Calculate the energy deposit in a water phantom • Calculate the Bragg peak

4. Bragg peak test • The CATANA group performs experimental measurements of the proton Bragg peak (see Giorgio’s talk) • Scope of the project: ~63 MeV proton Bragg peak validation • The Geant4 simulation models accurately the set-up of the experimental measurements • Comparison between the experimental measurements and the results of the simulation activating alternative electromagnetic and hadronic physics models

5. Physics component The user can choose: • to activate EM physics only • to add on top the hadronic physics • to activate alternative models for both EM and hadronic physics Modularised physics component Particles: p, d, t, α, ions, e-, e+, pions, neutrons, muons

6. EM Physics models • The user can choose to activate for protons the following alternative models: • Low Energy - ICRU 49, • Low Energy - Ziegler77, • Low Energy - Ziegler85, • Low Energy Ziegler 2000, • Standard • The user can choose for d, t, α, ions the alternative models: • Low Energy ICRU, • Standard • In the case of Low Energy Physics, also the nuclear stopping power is activate

7. EM Physics models • The user can choose to activate for e-: • LowEnergy EEDL, • LowEnergy Penelope, • Standard • The user can choose to activate for e+: • LowEnergy Penelope, • Standard • The user can choose to activate for gamma: • LowEnergy EPDL, • LowEnergy Penelope, • Standard

8. Hadronic physics • Elastic scattering • Inelastic scattering • Alternative approaches for p, n, pions • LEP ( E < 100 MeV) and Binary Ion model ( E > 80 MeV) for d, t, α • Neutron fission and capture

9. Hadronic physics list The user can select alternative hadronic physics lists for protons, pions and neutrons • Precompound model • Binary model + Precompound model ( with all the option showed above) • Bertini model • LEP • + default evaporation • + GEM evaporation • + default evaporation + Fermi Break-up • + GEM evaporation + Fermi Break-up

10. Strategy • Activate the electromagnetic physics only • Add on top the hadronic physics component • Simulate the Bragg peak with combinations of e.m. and hadronic physics models • Alternative hadronic physics models: • Precompound model only • +default evaporation • + GEM evaporation • + default evaporation + Fermi Break-up • + GEM evaporation + Fermi Break-up • Binary + Precompound model • Bertini model • LEP model • Alternative e.m. physics models: • Standard physics • Low Energy physics: • - ICRU49, • - Ziegler77, • - Ziegler85, • - SRIM2000

11. Bragg peak test • Compare experimental Bragg peak with simulation results • Quantitative analysis of the results • With the Statistical toolkit • Kolmogorov-Smirnov test to compare simulated and experimental set-up

12. First results

13. Projects for the future • Physics validation of the Bragg peak at higher proton beam energies • Physics validation of ion Bragg peak • Open to collaboration • Plan to publish a paper