Transcript Implementation of Penelope physics in Geant4

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
Geant4 electron Bremsstrahlung
2 electromagnetic physics packages
Standard
Low Energy
3 Bremsstrahlung processes
G4eBremsstrahlung
Tsai
angular distribution
G4eLowEnergyBremsstrahlung
Tsai
2BN
2BS
angular distributions
G4PenelopeBremsstrahlung
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Validation of Geant4 EM physics
Ongoing large-scale project
K. Amako et al.,
IEEE Trans. Nucl. Sci. 52 (2005) 910
NSS 2006
N
I
S
T
Photon mass attenuation coefficient
Range, Stopping power (e, p, a)
Atomic relaxation (fluorescence, Auger effect)
Proton Bragg peak
Electron Bremsstrahlung
Bremsstrahlung
Difficult to find reference data
1st validation cycle:
focus on low energy
Difficult to disentangle effects
Thin/thick target experiments
(because of the continuous part)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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The experimental set-up
e- beam(70 keV-10 MeV) incident on
a slab of material
Electrons and d-rays are absorbed
Bremsstrahlung photons can be transmitted
Photon
(energy, θ)
θ
electrons
Yield, Energy and Polar Angle
of the emitted photons
Quantitatitative comparison
of experimental - simulated distributions
Z axis
Secondary production
threshold = 0.5 mm
Statistical Toolkit
Goodness-of-Fit test
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Preliminary results
Data sets
Work in progress!
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
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Double differential s at 2.7 MeV
on thin (2.63 mg/cm2) Be target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 4.5 MeV
on thin (2.63 mg/cm2) Be target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 9.7 MeV
on thin (2.63 mg/cm2) Be target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 2.7 MeV
on thin (0.878 mg/cm2) Al target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 2.7 MeV
on thin (0.878 mg/cm2) Al target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
data
+ simulation
Energy (MeV)
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 4.5 MeV
on thin (0.878 mg/cm2) Al target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
data
+ simulation
Energy (MeV)
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 9.7 MeV
on thin (0.878 mg/cm2) Al target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
data
+ simulation
Energy (MeV)
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 2.7 MeV
on thin (0.209 mg/cm2) Au target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 4.5 MeV
on thin (0.209 mg/cm2) Au target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
Energy (MeV)
data
+ simulation
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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Double differential s at 9.7 MeV
on thin (0.209 mg/cm2) Au target
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data
+ simulation
data
+ simulation
Energy (MeV)
Energy (MeV)
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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500 keV
Angular distribution
Ethr = 46 keV
W.E. Dance et al., Journal of
Applied Physics 39 (1968) 2881
500 keV electrons on
Al (0.548 g/cm2) and Fe (0.257 g/cm2)
Thick target experiment
Standard package
Red = data
Black = simulation
Absolute comparison
o  Al
  Fe
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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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
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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
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1 MeV
Angular distribution
Standard package
Same test for 1 MeV primary
electrons (threshold: 50 keV)
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
Absolute comparison
o  Al
  Fe
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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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
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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
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Integral g yield
Total g yield on Al integrated
on  (0  p) and
on energy (Eth  Emax)
Standard process
o  data
  simul.
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
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Angular distributions
70 keV
Low Energy Package
Penelope
Penelope
Standard
TSAI
Low Energy
(TSAI)
2BS
Angle (deg)
2BN
Angle (deg)
Angular distribution of photons is strongly model-dependent
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade
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R. Ambrose et al., Nucl. Instr.
Meth. B 56/57 (1991) 327
photon
direction
70 keV e-
Intensity/Z (eV/sr keV)
Energy distribution at 70 keV
Penelope
Low Energy TSAI
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
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Penelope
Photon energy (keV)
Intensity/Z (eV/sr keV)
Intensity/Z (eV/sr keV)
Relative comparison at 70 keV
Low Energy TSAI
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
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Conclusions

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A project is in progress to test all Geant4
Bremsstrahlung models
Rigorous, quantitative comparison against
experimental data
Preliminary results at low energies
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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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