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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Electromagnetic physics validation Katsuya Amako,Susanna Guatelli, Vladimir Ivanchenko, Michel Maire, Barbara Mascialino, Koichi Murakami, Sandra Parlati, Andreas Pfeiffer, Maria Grazia Pia, Takashi Sasaki, Lazslo Urban Geant4 Workshop Catania, October 4 th -9 th 2004

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 The project The project is based on a geographically spread collaboration: INFN Genova INFN Gran Sasso Standard Group KEK THANKS TO KOICHI MURAKAMI, TAKASHI SASAKI, KATSUYA AMAKO FOR THE VERY FRUITFUL COLLABORATION! Preliminary results were presented at last Geant4 Workshop and at IEEE-NSS in Portland. Now the project has reached a mature state.

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Aim of the project Project for the validation of all Geant4 electromagnetic models against established references The project s made-up by two parts: PHYSICAL TEST GOODNESS-OF-FIT TESTING test50 Goodness-of-Fit statistical toolkit Quantitative statistical comparisons allow: - an evaluation of Geant4 physics goodness - how the specific models behave in the same experimental condition POSSIBILITY OF CHOOSING THE MOST APPROPRIATE MODEL Chi-squared stability study

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon Attenuation Coefficient Photon Cross Sections (attenuation coefficients with only one process activated) Electrons CSDA range and Stopping Power (no multiple scattering, no energy fluctuations) Protons CSDA range and Stopping Power (no multiple scattering, no energy fluctuations) Alpha particles CSDA range and Stopping Power (no multiple scattering, no energy fluctuations) First phase: validation against the NIST database Elements: Be, Al, Si, Fe, Ge, Ag, Cs, Au, Pb, UEnergy range: 1 keV – 100 GeV Testing activity has been automatised (thanks to Sandra Parlati and Koichi Murakami)

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photons: attenuation coefficient χ 2 /ν stability study BeZ dependency?

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon attenuation coefficient: statistical results χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be1.260.160.0811.010.45 Al0.3110.0710.341 Si0.3210.1010.560.97 Fe0.1110.0810.201 Ge0.1510.0510.281 Ag0.2210.1510.451 Cs0.1910.3710.810.75 Au0.0810.0510.710.86 Pb0.1310.0810.520.99 U0.0410.0610.750.93 NIST – XCOM LowE Livermore NIST – XCOM LowE Penelope NIST – XCOM Standard

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photons: photoelectric cross section χ 2 /ν stability study Be Cs Z dependency?

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon photoelectric cross section: statistical results χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be0.051 10.820.63 Al0.0510.0310.271 Si0.0710.0210.171 Fe0.0910.0510.111 Ge0.2110.0810.071 Ag0.0710.0510.071 Cs0.520.940.2111.180.27 Au0.1410.1510.570.93 Pb0.2510.3510.510.96 U0.3510.370.990.420.99 NIST – XCOM LowE Livermore NIST – XCOM LowE Penelope NIST – XCOM Standard

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photons: Compton cross section The 1keV deviation effect is evident in both LowE Penelope and Standard packages χ 2 /ν = with the 1 keV point without the 1 keV point LowE Penelope 17.300.46 Standard9.01.65 As an example, let us consider Ag:

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon Compton cross section: statistical results χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be0.1210.0710.530.85 Al0.0710.1810.490.86 Si1.610.090.1510.600.77 Fe0.3010.690.750.270.99 Ge0.1311.680.070.380.96 Ag0.0910.650.790.460.92 Cs0.1410.360.970.620.72 Au0.1610.410.941.040.41 Pb0.2311.310.211.180.29 U0.1110.1310.081 NIST – XCOM LowE Livermore NIST – XCOM LowE Penelope NIST – XCOM Standard

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Compton cross sections χ 2 /ν stability study (without the E=1 keV point) χ 2 /ν stability study Si Pb Ge Au

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photons: pair production cross section Beryllium χ 2 /ν stability study Be (not compatible with the NIST) deviations χ 2 /ν stability study

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon pair production cross section: statistical results χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be0.0518.07<0.0017.01<0.001 Al0.0710.830.611.070.39 Si0.0910.760.690.930.52 Fe0.0710.320.990.300.99 Ge0.0410.2510.181 Ag0.0610.1510.231 Cs0.2410.540.890.300.99 Au0.0810.0910.231 Pb0.1110.0810.221 U0.0911.1810.260.99 NIST – XCOM LowE Livermore NIST – XCOM LowE Penelope NIST – XCOM Standard Removing the 1 keV point

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photons: Rayleigh cross section deviations χ 2 /ν stability study Ge Pb U Au Fe Si Al

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Photon Rayleigh cross section: statistical results χ 2 /ν p-value χ 2 /ν p-value Be0.270.990.171 Al1.150.9724.86<0.001 Si0.680.7725.08<0.001 Fe0.27111.08<0.001 Ge17.97<0.0011.060.39 Ag1.100.361.740.08 Au1.900.0518.99<0.001 Pb8.40<0.00122.10<0.001 U11.31<0.00128.19<0.001 NIST – XCOM LowE Livermore NIST – XCOM LowE Penelope Test results are not consistent

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 The disagreement between NIST reference data and data coming from the recent library EPDL97 (provided by Lawrence Livermore National Laboratory) within the range of energies between 1 keV and 1 MeV has been already underlined and discussed in a recent paper by Zaidi *. In his paper Zaidi concluded that EPDL97 is the most up-dated, complete and consistent data library available at the moment. For these features, it should be considered as a standard. Critical discussion of this result * Zaidi H., 2000, Comparative evaluation of photon cross section libraries for materials of interest in PET Monte Carlo simulation IEEE Transaction on Nuclear Science 47 2722-35

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Electrons: stopping power χ 2 /ν stability study NIST – ESTAR LowE Livermore NIST – ESTAR LowE Penelope NIST – ESTAR Standard χ 2 /ν = -0.032 + 0.0074 Z R 2 =0.995 p<0.0001 χ 2 /ν = -0.046 + 0.0073 Z R 2 =0.989 p<0.0001 The three models are equivalent Strange effect (as a function of Z) BEST FIT BEST FIT BEST FIT

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Electrons stopping power: statistical results χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be0.0310.021 1 Al0.0610.0510.061 Si0.0710.061 1 Fe0.1510.1410.131 Ge0.1810.1710.151 Cs0.3610.3510.311 Au0.570.960.560.960.540.97 Pb0.580.950.570.960.560.97 U0.650.910.640.920.640.92 NIST – ESTAR LowE Livermore NIST – ESTAR LowE Penelope NIST – ESTAR Standard

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Electrons: CSDA range χ 2 /ν stability study Ag (to be explained) The three models are equivalent

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 χ 2 /ν p-value χ 2 /ν p-value χ 2 /ν p-value Be0.2110.2410.171 Al0.051 10.041 Si0.041 1 1 Fe0.021 1 1 Ge0.0210.0110.021 Ag0.1011.060.390.021 Cs0.00910.00610.0081 Au0.00510.00410.0051 Pb0.00510.0041 1 U 10.0031 1 NIST – ESTAR LowE Livermore NIST – ESTAR LowE Penelope NIST – ESTAR Standard Electrons CSDA range: statistical results

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 LowE Ziegler 85 LowE Ziegler 2000 ICRU Standard At low energies: free electron gas model At middle energies (~ MeV): parametrisations At high energies: Bethe Bloch Statistical comparison cannot lead to a real physics validation, but we can only compare two different models (NIST – Ziegler) Protons and alpha particles NIST database

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Protons: stopping power χ 2 /ν stability study LowE ICRU Standard LowE Ziegler 85 lOWe Ziegler 2000 NIST - PSTAR

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Protons stopping power: statistical results χ 2 /ν p p p p Be0.00810.4110.660.940.011 Al0.0210.0510.0610.021 Si0.00810.4110.810.790.011 Fe0.0210.031 10.021 Ge0.1210.5310.720.890.111 Ag0.0610.1510.1010.041 Au0.0810.2710.1710.091 Pb0.0610.1210.170.210.051 U0.1011.280.121.280.120.091 NIST – PSTAR LowE ICRU49 NIST – PSTAR LowE Ziegler85 NIST – PSTAR Standard NIST – PSTAR LowE Ziegler2000

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Protons: CSDA range χ 2 /ν stability study LowE ICRU Standard LowE Ziegler 85 LowE Ziegler 2000 NIST - PSTAR

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Protons CSDA range: statistical results χ 2 /ν p p p p Be0.00510.1111.030.410.471 Al0.0310.011 10.271 Si0.0210.2910.320.990.231 Fe0.0610.2010.1810.321 Ge0.1310.2610.2710.241 Ag0.0810.3410.151 1 Au0.0910.910.620.4710.141 Pb0.0910.2110.170.990.121 U0.1111.230.161.180.210.131 NIST – PSTAR LowE ICRU49 NIST – PSTAR LowE Ziegler85 NIST – PSTAR Standard NIST – PSTAR LowE Ziegler2000

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Alpha particles: stopping power WORK IN PROGRESS LowE ICRU Standard LowE Ziegler 77 NIST - ASTAR

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Alpha particles: CSDA range WORK IN PROGRESS LowE ICRU Standard LowE Ziegler 77 NIST - ASTAR

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Statistical comparisons (II) Concerning alpha particles, this is the second iteration of production and analysis since last July. This because thanks to the quantitative analysis we could detect a conceptual flaw in physics tables treatment for both protons and alpha particles. Systematic data analysis allowed to improve the physical models.

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Low Energy Livermore is the most compatible with the NIST reference (Rayleigh scattering is a special case) Low Energy Penelope is quite compatible with NIST reference except for some problems exhibited in Compton scattering and pair production cross sections Standard electrons are compatible with NIST, photons are quite compatible, but exhibit some problems SUMMARY: photons and electrons

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 While NIST represents an established reference for photon and electron processes, the reference for protons and alpha processes in controversial at least in the lower energy ranges. Two reference data compilations ICRU/NIST and Ziegler. Quantitative comparisons available for all NIST quantities for protons and alpha particles. SUMMARY: protons and alpha particles

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Conclusions Validation of all Geant4 Electromagnetic models against the NIST database Quantitative statistical analysis on all the comparisons Fully automated testing system (thanks to Sandra Parlati and Koichi Murakami) Objective comparison among Geant4 models (with respect to the NIST reference) Mature project and results will be presented at IEEE-NSS – paper submitted for publication next month

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Barbara MascialinoGeant4 WorkshopCatania, October 4-9 2004 Future perspectives Final states angular distributions and spectra The first results will be shown and discussed in the parallel section Physics Book introductory talk by Susanna Guatelli

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