1. Maria Grazia Pia, INFN Genova Geant4 Physics Validation Geant4 Space User Workshop Pasadena, 6-10 November 2006 M.G. Pia On behalf of the LowE EM and Advanced Examples Working Groups http://www.ge.infn.it/geant4/lowE Pablo Cirrone Giacomo Cuttone Francesco Di Rosa Susanna Guatelli Alfonso Mantero Barbara Mascialino Luciano Pandola Andreas Pfeiffer MG Pia Pedro Rodrigues Giorgio Russo Andreia Trindade Valentina Zampichelli

2. Maria Grazia Pia, INFN Genova Geant4 Toolkit objective criteria Provide objective criteria to evaluate Geant4 physics models precision –Document their precision against experimental data allsystematically –Test all Geant4 physics models systematically –Quantitative statistical methods –Quantitative tests with rigorous statistical methods Wide set of physics processes and models Versatility of configuration according to use cases How accurate is Geant4 physics modelling? most appropriate model Which is the most appropriate model for my simulation?

3. Maria Grazia Pia, INFN Genova Verification and Validation of Geant4 physics Verification compliance of the software results with the specifications (the underlying physics model) = compliance of the software results with the specifications (the underlying physics model) –Unit tests (at the level of individual Geant4 classes)Validation comparison against experimental data = comparison against experimental data (Goodness-of-Fit) –Quantitative estimate of the agreement between Geant4 simulation and reference data through statistical methods (Goodness-of-Fit) systematic quantitative A systematic, quantitative validation of Geant4 physics models against reference experimental data is essential to establish the reliability of Geant4-based applications

4. Maria Grazia Pia, INFN Genova Strategy –Rigorous methods –Systematic, quantitative comparisons –Address all modeling options –Statistical analysis of compatibility with experimental data Adopt the same method also for hadronic physics validation –Start from the bottom (low energy) –Progress towards higher energy based on previous sound assessments 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. 910-918 Statistical Toolkit Goodness-of-Fit test Quantitatitative comparison of experimental - simulated distributions

5. Maria Grazia Pia, INFN Genova Statistical Toolkit Launched as an ESA project 2 nd development cycle –Released April 2006 Goodness-of-fit tests –Binned distributions –Unbinned distributions –Performance analysis –Power analysis The most complete software tool for 2-sample GoF tests IEEE Trans. Nucl. Sci., December 2006 25 July 2006.

6. Maria Grazia Pia, INFN Genova Recent validation activities Atomic relaxation –Fluorescence and Auger transition energies Bremsstrahlung –Angular distributions Proton Bragg peak –Electromagnetic interactions –Elastic scattering –Pre-equilibrium –Nuclear de-excitation + other validation activities in Advanced Examples More details: see talks at IEEE NSS 2006

7. Maria Grazia Pia, INFN Genova Geant4 Atomic Relaxation Geant4 Atomic Relaxation modelsFluorescence Auger electron emission It is used by Geant4 packages: Low Energy Electromagnetic –Photoelectric effect –Low Energy electron ionisation –Low Energy proton ionisation (PIXE) –Penelope Compton scattering Hadronic Physics –Nuclear de-excitation –Radioactive decay Geant4 Low Energy Electromagnetic package takes into account the detailed atomic structure of matter and the related physics processes It includes a package for Atomic Relaxation –Simulation of atomic de-excitation resulting from the creation of a vacancy in an atom by a primary process These physics models are relevant to many diverse experimental applications

8. Maria Grazia Pia, INFN Genova Courtesy ESA Space Environment & Effects Analysis Section X-Ray Surveys of Asteroids and Moons Induced X-ray line emission: indicator of target composition (~100  m surface layer) Cosmic rays, jovian electrons Geant3.21 ITS3.0, EGS4 Geant4 Solar X-rays, e, p Courtesy SOHO EIT C, N, O line emissions included Geant4 fluorescence Geant4 fluorescence Original motivation from astrophysics requirements Wide field of applications beyond astrophysics 250 keV

9. Maria Grazia Pia, INFN Genova Atomic Relaxation in Geant4 Two steps: 1.Identification of the atomic shell where a vacancy is created by a primary process (photoelectric, Compton, ionisation) cross sections The creation of the vacancy is based on the calculation of the primary process cross sections relative to the shells of the target atom Cross section modeling and calculation specific to each process products 2.Generation of the de-excitation chain and its products Common package, used by all vacancy-creating processes Geant4 Atomic Relaxation Generation of fluorescence photons and Auger electrons Determination of the energy of the secondary particles produced

10. Maria Grazia Pia, INFN Genova Modelling foundation in Geant4 Low Energy Electromagnetic Package Calculation of shell cross sections EPDL97 –Based on the EPDL97 Livermore Library for photoelectric effect EEDL –Based on the EEDL Livermore Library for electron ionisation –Based on Penelope model for Compton scattering Detailed atom description and calculation of the energy of generated photons/electrons EADL –Based on the EADL Livermore Library

11. Maria Grazia Pia, INFN Genova Validation of Geant4 Atomic Relaxation Previous partial validation studies (collaboration with ESA Advanced Concepts Division) –Pure materials: limited number of elements examined –Complex materials: complex experimental set-up, large uncertainties on the target material composition NIST database Systematic validation project: NIST database as reference Authoritative, systematic collection of experimental data

12. Maria Grazia Pia, INFN Genova Method and tools Geant4 test code to generate fluorescence and Auger transitions from all elements –Geant4 Atomic Relaxation handles 6 ≤ Z ≤ 100 Selection of experimental data subsets from NIST database –The NIST database also contains data from theoretical calculations Comparison of simulated/NIST data with Goodness-of-Fit test –Data grouped for the comparison as a function of Z according to the initial vacancy and transition type –Statistical Toolkit (http://www.ge.infn.it/statisticaltoolkit)http://www.ge.infn.it/statisticaltoolkit –Kolmogorov-Smirnov test p-value –The result of the agreement is expressed through the p-value of the test

13. Maria Grazia Pia, INFN Genova Fluorescence – Shell vacancy K Shell-end Kolmogorov- Smirnov D p-value 50.01881 60.01851 100.01721 130.06671 140.05881 180.07141 190.07141 Geant4 ○ NIST Z E (keV)

14. Maria Grazia Pia, INFN Genova Fluorescence – Shell vacancy L1 Shell-end Kolmogorov- Smirnov D p-value 100.01921 110.01751 130.02501 140.02561 180.02941 190.03121 210.14290.997085 220.05881 Geant4 ○ NIST

15. Maria Grazia Pia, INFN Genova Fluorescence – Shell vacancy L2 Shell-end Kolmogorov- Smirnov D p-value 80.01471 110.04351 130.01391 160.02041 190.05261 210.01961 240.07141 Geant4 ○ NIST

16. Maria Grazia Pia, INFN Genova Fluorescence – Shell vacancy L3 Shell-end Kolmogorov- Smirnov D p-value 80.01451 100.05881 110.05561 130.01821 140.01791 160.02001 180.06671 190.05561 210.05881 220.05001 Geant4 ○ NIST

17. Maria Grazia Pia, INFN Genova Auger electron emission Scarce experimental data in the NIST database –Often multiple data for the same Auger transition: ambiguous reference Analysis in progress: comparison of Geant4 simulation data against the NIST subset of experimental data Preliminary results: good qualitative agreement as in the case of X-ray fluorescence –Rigorous statistical analysis to be completed, will be included in publication

18. Maria Grazia Pia, INFN Genova Geant4 electron Bremsstrahlung 2 electromagnetic physics packages Standard Low Energy 3 Bremsstrahlung processes G4eBremsstrahlung G4PenelopeBremsstrahlung G4eLowEnergyBremsstrahlung Tsai 2BN2BS angular distributions angular distribution

19. Maria Grazia Pia, INFN Genova Validation of Geant4 EM physics K. Amako et al., IEEE Trans. Nucl. Sci. 52 (2005) 910 Ongoing large-scale project Photon mass attenuation coefficient Range, Stopping power (e, p,  ) NISTNIST NSS 2006 Atomic relaxation (fluorescence, Auger effect) Proton Bragg peak Electron Bremsstrahlung Bremsstrahlung Difficult to find reference data Thin/thick target experiments Difficult to disentangle effects (because of the continuous part) 1 st validation cycle: focus on low energy

20. Maria Grazia Pia, INFN Genova Angular distributions Angular distribution of photons is strongly model-dependent Angle (deg) Penelope Standard Low Energy (TSAI) 70 keV Angle (deg) Penelope TSAI 2BS 2BN Low Energy Package

21. Maria Grazia Pia, INFN Genova The experimental set-up e - beam(70 keV-10 MeV) incident on a slab of material Z axis electrons Photon (energy, θ) θ YieldEnergyPolar Angle Yield, Energy and Polar Angle of the emitted photons Electrons and  -rays are absorbed Bremsstrahlung photons can be transmitted Secondary production threshold = 0.5  m Quantitatitative comparison of experimental - simulated distributions Statistical Toolkit Goodness-of-Fit test in progress

22. Maria Grazia Pia, INFN Genova Data sets N. Starfelt et al., Phys. Rev. 102 (1956) 1598 2.7 4.59.7 Thin target: Be, Al, Au - 2.7, 4.5, 9.7 MeV Double differential cross sections W.E. Dance et al., Journal of Appl. Phys. 39 (1968) 2881 0.5 1 Thick target: Al, Fe – 0.5, 1 MeV Double differential cross sections Integrated  yield R. Ambrose et al., NIM B 56/57 (1991) 327 Absolute and relative yield Preliminary results Work in progress! Simulation production: still running Statistical analysis: still preliminary, to be completed

23. Maria Grazia Pia, INFN Genova Double differential  at 2.7 MeV on thin (2.63 mg/cm 2 ) Be target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

24. Maria Grazia Pia, INFN Genova Double differential  at 4.5 MeV on thin (2.63 mg/cm 2 ) Be target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation Preliminary Kolmogorov-Smirnov p-value = 0.17 Preliminary Kolmogorov-Smirnov p-value = 0.13

25. Maria Grazia Pia, INFN Genova Double differential  at 9.7 MeV on thin (2.63 mg/cm 2 ) Be target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

26. Maria Grazia Pia, INFN Genova Double differential  at 2.7 MeV on thin (0.878 mg/cm 2 ) Al target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

27. Maria Grazia Pia, INFN Genova Double differential  at 2.7 MeV on thin (0.878 mg/cm 2 ) Al target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

28. Maria Grazia Pia, INFN Genova Double differential  at 4.5 MeV on thin (0.878 mg/cm 2 ) Al target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

29. Maria Grazia Pia, INFN Genova Double differential  at 9.7 MeV on thin (0.878 mg/cm 2 ) Al target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

30. Maria Grazia Pia, INFN Genova Double differential  at 2.7 MeV on thin (0.209 mg/cm 2 ) Au target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

31. Maria Grazia Pia, INFN Genova Double differential  at 4.5 MeV on thin (0.209 mg/cm 2 ) Au target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

32. Maria Grazia Pia, INFN Genova Double differential  at 9.7 MeV on thin (0.209 mg/cm 2 ) Au target Energy (MeV) N. Starfelt et al., Phys. Rev. 102 (1956) 1598 data + simulation data + simulation

33. Maria Grazia Pia, INFN Genova Angular distribution Red = data Black = simulation o  Al  Fe Standard package Absolute comparison W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 500 keV electrons on Al (0.548 g/cm 2 ) and Fe (0.257 g/cm 2 ) Thick target experiment 500 keV Preliminary  2 test p-value = 0.10

34. Maria Grazia Pia, INFN Genova Angular distribution precise agreement! W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 500 keV Preliminary  2 test p-value = 0.68 Preliminary  2 test p-value = 0.03

35. Maria Grazia Pia, INFN Genova Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 500 keV Preliminary  2 test p-value not meaningful Preliminary  2 test p-value = 0.33

36. Maria Grazia Pia, INFN Genova Angular distribution Red = data Black = simulation o  Al  Fe Same test for 1 MeV primary electrons (threshold: 50 keV) Absolute comparison W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 Targets: Al (0.548 g/cm 2 ) and Fe (0.613 g/cm 2 ) 1 MeV Preliminary Fe  2 test p-value not meaningful

37. Maria Grazia Pia, INFN Genova Angular distribution Good agreement for Al - Reasonable also for Fe (2BN) precise agreement! W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 1 MeV Preliminary Fe  2 test p-value = 0.06 Preliminary Fe  2 test p-value = 0.68

38. Maria Grazia Pia, INFN Genova Angular distribution 2BS: good for Al and Fe (except in the backward direction) W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 1 MeV Preliminary Fe  2 test p-value = 0.36 Preliminary Fe  2 test p-value not meaningful

39. Maria Grazia Pia, INFN Genova Integral  yield Total  yield on Al integrated on (0   ) and on energy (E th  E max ) Also available for other flavours of Geant4 Bremsstrahlung models o  data  simul. W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 Further investigation in progress Preliminary Preliminary

40. Maria Grazia Pia, INFN Genova Energy distribution at 70 keV 70 keV electrons impinging on Al (25.4 mg/cm 2 ) Penelope Low Energy - TSAI Photon energy (keV) Intensity/Z (eV/sr keV) 70 keV e - photon direction 45 deg R. Ambrose et al., Nucl. Instr. Meth. B 56/57 (1991) 327

41. Maria Grazia Pia, INFN Genova Relative comparison at 70 keV Relative comparison (45° direction) Shapes of the spectra are in good agreement Intensity/Z (eV/sr keV) Photon energy (keV) Penelope Low Energy - TSAI Intensity/Z (eV/sr keV)

42. Maria Grazia Pia, INFN Genova Proton Bragg peak Compare various Geant4 electromagnetic models Assess 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 Physics Space Science Astronauts’ radiation protection

43. Maria Grazia Pia, INFN Genova Relevant Geant4 physics 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 Elastic scattering –Parameterized models –Bertini Intra-nuclear cascade –Bertini cascade –Binary cascade Hadronic Electromagnetic Subset of results shown here Full set of results in publication coming shortly

44. Maria Grazia Pia, INFN Genova Experimental data CATANA hadrontherapy facility in Catania, Italy –high precision experimental data satisfying rigorous medical physics protocols –Geant4 Collaboration members Validation measurements Markus Ionization chamber 2 mm Sensitive Volume = 0.05 cm 3 Resolution 100  m Markus Chamber

45. Maria Grazia Pia, INFN Genova Geant4 simulation Accurate reproduction of the experimental set-up 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 Ad hoc beam line set-up for Geant4 validation to enhance peculiar effects of physics processes E proton = 63.5 MeV  E = 300 keV

46. Maria Grazia Pia, INFN Genova Electromagnetic 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

47. Maria Grazia Pia, INFN Genova Electromagnetic processes Standard EM: p, ions, , e- e+p-value CvMKSAD Left branch 0.418 Right branch 0.736 Whole curve 0.438 CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data Standard EM

48. Maria Grazia Pia, INFN Genova Electromagnetic processes Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+p-value CvMKSAD Left branch 0.530 Right branch 0.985 Whole curve 0.676 CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data LowE EM – ICRU49

49. Maria Grazia Pia, INFN Genova Electromagnetic processes Low Energy EM – Ziegler 1977: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ 1 M events mm Geant4 Experimental data LowE EM – Ziegler 1977 CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test

50. Maria Grazia Pia, INFN Genova Electromagnetic processes LowE EM – Ziegler 1985 Low Energy EM – Ziegler 1985: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ Subject to further investigation 1 M events mm Geant4 Experimental data

51. Maria Grazia Pia, INFN Genova Electromagnetic processes Low Energy EM – Ziegler 2000: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ Subject to further investigation 1 M events mm Geant4 Experimental data LowE EM – Ziegler 2000

52. Maria Grazia Pia, INFN Genova Electromagnetic processes Summary p-value LowE ICRU49 LowE Ziegler 1977 Standard Left branch (CvM) 0.5300.418 Right branch (KS) 0.985 0.736 Whole curve (AD) 0.6760.438 CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test LowE – ICRU49 Best EM option: LowE – ICRU49 Selected for further EM + Hadronic tests

53. Maria Grazia Pia, INFN Genova Electromagnetic processes + Elastic scattering Elastic scattering options  HadronElastic process with LElastic model  HadronElastic process with BertiniElastic model  UHadronElastic process with HadronElastic model

54. Maria Grazia Pia, INFN Genova EM + Elastic scattering Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ LElastic HadronElastic with LElasticp-value CvMKSAD Left branch 0.522 Right branch 0.985 Whole curve 0.697 LowE EM – ICRU49 LElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data

55. Maria Grazia Pia, INFN Genova EM + Elastic scattering Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ HadronElastic UHadronElastic with HadronElasticp-value CvMKSAD Left branch 0.490 Right branch 0.735 Whole curve 0.669 LowE EM – ICRU49 HadronElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 0.5 M events mm Geant4 Experimental data

56. Maria Grazia Pia, INFN Genova Electromagnetic processes + Elastic scattering + Hadronic inelastic scattering Hadronic Inelastic options  Precompound with Default Evaporation  Precompound with GEM Evaporation  Precompound with Default Evaporation + Fermi Break-up  Bertini

57. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ LElastic HadronElastic with LElastic Precompound Default Evaporation Precompound with Default Evaporationp-value CvMKSAD Left branch 0.836 Right branch 0.985 Whole curve 0.946 LowE EM – ICRU49 LElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data Precompound default

58. Maria Grazia Pia, INFN Genova EM + hadronic physics Standard EM: p, ions, , e- e+ LElastic HadronElastic with LElastic Precompound Default Evaporation Precompound with Default Evaporationp-value CvMKSAD Left branch 0.648 Right branch 0.760 Whole curve 0.666 CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data Standard EM LElastic Precompound default

59. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ HadronElastic Precompound Default Evaporation UHadronElastic with HadronElastic Precompound with Default Evaporationp-value CvMKSAD Left branch 0.973 Right branch 0.985 Whole curve 0.982 LowE EM – ICRU49 HadronElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 0.5 M events mm Geant4 Experimental data Precompound default

60. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ LElastic HadronElastic with LElastic Precompound GEM Evaporation Precompound with GEM Evaporationp-value CvMKSAD Left branch 0.667 Right branch 0.985 Whole curve 0.858 LowE EM – ICRU49 LElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 0.5 M events mm Geant4 Experimental data Precompound with GEM Evaporation

61. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ LElastic HadronElastic with LElastic Precompound Fermi Break-up Precompound with Fermi Break-upp-value CvMKSAD Left branch 0.814 Right branch 0.985 Whole curve 0.945 LowE EM – ICRU49 LElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 0.5 M events mm Geant4 Experimental data Precompound with Fermi Break-up

62. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ LElastic HadronElastic with LElastic Bertini Inelastic p-value CvMKSAD Left branch 0.790 Right branch 0.985 Whole curve 0.936 LowE EM – ICRU49 LElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 1 M events mm Geant4 Experimental data Bertini Inelastic

63. Maria Grazia Pia, INFN Genova EM + hadronic physics Low Energy EM – ICRU49: p, ions Low Energy EM – Livermore: , e- Standard EM:e+ HadronElastic with BertiniElastic Bertini Inelastic p-value CvMKSAD Left branch 0.977 Right branch 0.985 Whole curve 0.994 LowE EM – ICRU49 BertiniElastic CvM Cramer-von Mises test KS Kolmogorov-Smirnov test AD Anderson-Darling test 0.5 M events mm Geant4 Experimental data Bertini Inelastic

64. Maria Grazia Pia, INFN Genova Electromagnetic + Hadronic Summary p-value Standard 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) 0.6480.6670.7900.8140.8360.9730.977 Right branch (KS) 0.7600.985 Whole curve (AD) 0.6660.8580.9360.9450.9460.9820.994 Key ingredients electromagnetic  Precise electromagnetic physics elastic scattering  Good elastic scattering model pre-equilibrium  Good pre-equilibrium model

65. Maria Grazia Pia, INFN Genova …and behind everything Unified Process A rigorous software process Incremental and iterative lifecycle RUP  as process framework, tailored to the specific project Mapped onto ISO 15504

66. Maria Grazia Pia, INFN Genova Conclusion Geant4 physics validation carried on by a small, young team with rigorous methods –Underlying vision –Systematic approach –Rigorous quantitative analysis Current projects –Atomic relaxation: final results –Bremsstrahlung: preliminary results –Proton Bragg peak: mature stage, refinements by end 2006 Publications coming soon