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Validation of the Bremsstrahlung models

Validation of the Bremsstrahlung models. Susanna Guatelli, Barbara Mascialino, Luciano Pandola, Maria Grazia Pia, Pedro Rodrigues, Andreia Trindade. INFN Genova – INFN Gran Sasso Laboratory - LIP. IEEE Nuclear Science Symposium San Diego, 30 October – 4 November 2006.

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Validation of the Bremsstrahlung models

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  1. Validation of theBremsstrahlung models Susanna Guatelli, Barbara Mascialino, Luciano Pandola, Maria Grazia Pia, Pedro Rodrigues, Andreia Trindade INFN Genova – INFN Gran Sasso Laboratory - LIP IEEE Nuclear Science Symposium San Diego, 30 October – 4 November 2006

  2. Geant4 electron Bremsstrahlung 2 electromagnetic physics packages Standard Low Energy 3 Bremsstrahlung processes G4eLowEnergyBremsstrahlung G4eBremsstrahlung Tsai Tsai 2BN 2BS angular distribution angular distributions G4PenelopeBremsstrahlung S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  3. Validation of Geant4 EM physics Ongoing large-scale project NIST Photon mass attenuation coefficient Range, Stopping power (e, p, a) K. Amako et al., IEEE Trans. Nucl. Sci. 52 (2005) 910 Atomic relaxation (fluorescence, Auger effect) Proton Bragg peak Electron Bremsstrahlung NSS 2006 Bremsstrahlung Difficult to find reference data Thin/thick target experiments Difficult to disentangle effects (because of the continuous part) 1st validation cycle: focus on low energy S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  4. θ The experimental set-up e- beam(70 keV-10 MeV) incident on a slab of material Photon (energy, θ) Electrons andd-rays are absorbed Bremsstrahlung photons can be transmitted electrons Z axis Yield,EnergyandPolar Angleof theemitted photons Secondary production threshold = 0.5 mm Statistical Toolkit Goodness-of-Fit test Quantitatitative comparison of experimental - simulated distributions S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  5. Preliminary results Work in progress! Data sets N. Starfelt et al., Phys. Rev. 102 (1956) 1598 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 Thick target: Al, Fe – 0.5, 1 MeV Double differential cross sections Integrated g yield R. Ambrose et al., NIM B 56/57 (1991) 327 Absolute and relative yield S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  6. data data + + simulation simulation Double differentialsat 2.7 MeV on thin (2.63 mg/cm2) Be target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  7. data data + + simulation simulation Double differential s at 4.5 MeV on thin (2.63 mg/cm2) Be target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  8. data data + + simulation simulation Double differential s at 9.7 MeV on thin (2.63 mg/cm2) Be target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  9. data data + + simulation simulation Double differential s at 2.7 MeV on thin (0.878 mg/cm2) Al target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  10. data data + + simulation simulation Double differential s at 2.7 MeV on thin (0.878 mg/cm2) Al target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  11. data data + + simulation simulation Double differential s at 4.5 MeV on thin (0.878 mg/cm2) Al target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  12. data data + + simulation simulation Double differential s at 9.7 MeV on thin (0.878 mg/cm2) Al target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  13. data data + + simulation simulation Double differential s at 2.7 MeV on thin (0.209 mg/cm2) Au target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  14. data data + + simulation simulation Double differential s at 4.5 MeV on thin (0.209 mg/cm2) Au target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  15. data data + + simulation simulation Double differential sat 9.7 MeV on thin (0.209 mg/cm2) Au target N. Starfelt et al., Phys. Rev. 102 (1956) 1598 Energy (MeV) Energy (MeV) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  16. 500 keV Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 Ethr = 46 keV 500 keV electrons on Al (0.548 g/cm2) and Fe (0.257 g/cm2) Thick target experiment Standard package Red = data Black = simulation o  Al   Fe Absolute comparison S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  17. 500 keV Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 precise agreement! S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  18. 500 keV Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  19. 1 MeV Angular distribution Same test for 1 MeV primary electrons (threshold: 50 keV) Standard package W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 Targets: Al (0.548 g/cm2) and Fe (0.613 g/cm2) Red = data Black = simulation o  Al   Fe Absolute comparison S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  20. 1 MeV Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 precise agreement! Good agreement for Al - Reasonable also for Fe (2BN) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  21. 500 keV Angular distribution W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 2BS: good for Al and Fe (except in the backward direction) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  22. Integral g yield Total g yield on Al integrated on  (0  p) and on energy (Eth  Emax) Standard process W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881 o  dat a   simul. S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  23. 70 keV Angular distributions Low Energy Package Penelope Standard Low Energy (TSAI) Penelope TSAI 2BS 2BN Angle (deg) Angle (deg) Angular distribution of photons is strongly model-dependent S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  24. Energy distribution at 70 keV Penelope Low Energy - TSAI R. Ambrose et al., Nucl. Instr. Meth. B 56/57 (1991) 327 Intensity/Z (eV/sr keV) photon direction 70 keV e- 45 deg Photon energy (keV) 70 keV electrons impinging on Al (25.4 mg/cm2) S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  25. Relative comparison at 70 keV Low Energy - TSAI Penelope Intensity/Z (eV/sr keV) Intensity/Z (eV/sr keV) Photon energy (keV) Photon energy (keV) Relative comparison (45° direction) Shapes of the spectra are in good agreement S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

  26. Conclusions • A project is in progress to test all Geant4 Bremsstrahlung models • Rigorous, quantitative comparison against experimental data • Preliminary results at low energies • Power of the toolkit strategy • Geant4 models differ significantly at low energy S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade

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