validation of the bremsstrahlung models
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Validation of theValidation of the
Bremsstrahlung modelsBremsstrahlung models
Susanna Guatelli, Barbara Mascialino, Luciano
Pandola, Maria Grazia Pia, Pedro Rodrigues, Andreia
Trindade
IEEE Nuclear Science Symposium San Diego, 30 October – 4 November 2006
INFN Genova – INFN Gran Sasso Laboratory - LIP
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 2
Geant4 electron Bremsstrahlung
2 electromagnetic physics packages
StandarStandardd
Low Low EnergyEnergy
3 Bremsstrahlung processes
G4eBremsstrahlung
G4PenelopeBremsstrahlung
G4eLowEnergyBremsstrahlung
Tsai
Tsai
2BN 2BSangular distributionsangular distribution
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 3
Validation of Geant4 EM physics
K. Amako et al., IEEE Trans. Nucl. Sci. 52 (2005) 910
Ongoing large-scale Ongoing large-scale projectproject Photon mass attenuation
coefficientRange, Stopping power (e, p, )
NIST
NSS 2006Atomic relaxation (fluorescence, Auger effect)
Proton Bragg peakElectron Bremsstrahlung
BremsstrahluBremsstrahlungng
Difficult to find reference dataThin/thick target experiments
Difficult to disentangle effects(because of the continuous part)
1st validation cycle:
focus on low focus on low energyenergy
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 4
The experimental set-up
e- beam(70 keV-10 MeV) incident on a slab of material
Z axiselectrons
Photon(energy, θ)
θ
YieldYield, EnergyEnergy and Polar Polar AngleAngle of the emitted photons
Electrons and -rays are absorbed Bremsstrahlung photons can be
transmitted
Secondary production threshold = 0.5 m
Quantitatitative comparisonof experimental - simulated distributions
Statistical Statistical ToolkitToolkit
Goodness-of-Fit test
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 5
Data setsN. Starfelt et al., Phys. Rev. 102 (1956) 1598
Thin target: Be, Al, Au - 2.72.7, 4.5 4.5, 9.79.7 MeVDouble differential cross sections
W.E. Dance et al., Journal of Appl. Phys. 39 (1968) 2881
Thick target: Al, Fe – 0.50.5, 1 1 MeVDouble differential cross sectionsIntegrated yield R. Ambrose et al., NIM B 56/57 (1991) 327
Absolute and relative yield
Preliminary Preliminary resultsresults
Work in progress!Work in progress!
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 6
Double differential at 2.7 MeV on thin (2.63 mg/cm2) Be target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 7
Double differential at 4.5 MeV on thin (2.63 mg/cm2) Be target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 8
Double differential at 9.7 MeV on thin (2.63 mg/cm2) Be target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 9
Double differential at 2.7 MeV on thin (0.878 mg/cm2) Al target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 10
Double differential at 2.7 MeV on thin (0.878 mg/cm2) Al target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 11
Double differential at 4.5 MeV on thin (0.878 mg/cm2) Al target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 12
Double differential at 9.7 MeV on thin (0.878 mg/cm2) Al target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 13
Double differential at 2.7 MeV on thin (0.209 mg/cm2) Au target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 14
Double differential at 4.5 MeV on thin (0.209 mg/cm2) Au target
Energy (MeV) Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 15
Double differential at 9.7 MeV on thin (0.209 mg/cm2) Au target
Energy (MeV)
Energy (MeV)
N. Starfelt et al., Phys. Rev. 102 (1956) 1598
data+ simulation
data+ simulation
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 16
Angular distribution
Red = data
Black = simulation
o Al Fe
Standard package
Absolute comparison
Ethr = 46 keV W.E. Dance et al., Journal of Applied Physics 39 (1968)
2881500 keV electrons on
Al (0.548 g/cm2) and Fe (0.257 g/cm2)
Thick target experimentThick target experiment
500 keV500 keV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 17
Angular distribution
precise agreemen
t!
W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881
500 keV500 keV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 18
Angular distributionW.E. Dance et al., Journal of Applied Physics 39 (1968) 2881
500 keV500 keV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 19
Angular distribution
Red = data
Black = simulation
o Al Fe
Same test for 1 MeV primary electrons
(threshold: 50 keV)Standard package
Absolute comparison
W.E. Dance et al., Journal of Applied Physics 39 (1968)
2881Targets: Al (0.548 g/cm2)
and Fe (0.613 g/cm2)
1 MeV1 MeV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 20
Angular distribution
Good agreement for Al - Reasonable also for Fe (2BN)
precise agreemen
t!
W.E. Dance et al., Journal of Applied Physics 39 (1968) 2881
1 MeV1 MeV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 21
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
500 keV500 keV
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 22
Integral yieldTotal yield on Al
integrated
on (0 ) 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 23
Angular distributions
Angle (deg) Angle (deg)
Angular distribution of photons is strongly model-dependent
Penelope
Standard
Low Energy (TSAI)
Penelope
TSAI
2BS
2BN
70 keV70 keV
Low Energy PackageLow Energy Package
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 24
Energy distribution at 70 keV
70 keV electrons impinging on Al (25.4 mg/cm2)
Penelope
Low Energy - TSAI
Photon energy (keV)
Inte
nsi
ty/Z
(eV
/sr
keV
)
70 keV e-
photon directio
n45 deg
R. Ambrose et al., Nucl. Instr. Meth. B 56/57 (1991)
327
S. Guatelli, B. Mascialino, L. Pandola, M.G. Pia, P. Rodrigues, A. Trindade 25
Relative comparison at 70 keV
Relative comparison (45° direction) Shapes of the spectra are in good agreement
Inte
nsi
ty/Z
(eV
/sr
keV
)
Photon energy (keV)
Photon energy (keV)
PenelopeLow Energy
- TSAI
Inte
nsi
ty/Z
(eV
/sr
keV
)
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