Electromagnetic physics validation Katsuya Amako Susanna Guatelli Vladimir

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 Geant 4 Workshop Catania, October 4 th-9 th 2004 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

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

Aim of the project • Project for the validation of all Geant 4 electromagnetic models against established references • The project s made-up by two parts: PHYSICAL TEST GOODNESS-OF-FIT TESTING Goodness-of-Fit statistical toolkit Chi-squared stability study test 50 Quantitative statistical comparisons allow: - an evaluation of Geant 4 physics goodness - how the specific models behave in the same experimental condition POSSIBILITY OF CHOOSING THE MOST APPROPRIATE MODEL Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

First phase: validation against the NIST database 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) Elements: Be, Al, Si, Fe, Ge, Ag, Cs, Au, Pb, U Energy range: 1 ke. V – 100 Ge. V Testing activity has been automatised (thanks to Sandra Parlati and Koichi Murakami) Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photons: attenuation coefficient χ2/ν stability study Be Barbara Mascialino Geant 4 Workshop Z dependency? Catania, October 4 -9 2004

Photon attenuation coefficient: statistical results NIST – XCOM Low. E Livermore NIST – XCOM Low. E Penelope NIST – XCOM Standard χ2 /ν p-value Be Al Si 1. 26 0. 31 0. 32 0. 16 1 1 0. 08 0. 07 0. 10 1 1. 01 0. 34 0. 56 0. 45 1 0. 97 Fe Ge Ag Cs Au Pb U 0. 11 0. 15 0. 22 0. 19 0. 08 0. 13 0. 04 1 1 1 1 0. 08 0. 05 0. 15 0. 37 0. 05 0. 08 0. 06 1 1 1 1 0. 20 0. 28 0. 45 0. 81 0. 71 0. 52 0. 75 1 1 1 0. 75 0. 86 0. 99 0. 93 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photons: photoelectric cross section χ2/ν stability study Be Cs Z dependency? Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photon photoelectric cross section: statistical results NIST – XCOM Low. E Livermore Low. E Penelope Standard χ2 /ν p-value Be Al Si 0. 05 0. 07 1 1 1 0. 05 0. 03 0. 02 1 1 1 0. 82 0. 27 0. 17 0. 63 1 1 Fe Ge Ag Cs Au Pb U 0. 09 0. 21 0. 07 0. 52 0. 14 0. 25 0. 35 1 1 1 0. 94 1 1 1 0. 05 0. 08 0. 05 0. 21 0. 15 0. 37 1 1 1 0. 99 0. 11 0. 07 1. 18 0. 57 0. 51 0. 42 1 1 1 0. 27 0. 93 0. 96 0. 99 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photons: Compton cross section The 1 ke. V deviation effect is evident in both Low. E Penelope and Standard packages As an example, let us consider Ag: χ2/ν = with the without the 1 ke. V point Low. E Penelope 0. 46 Standard Barbara Mascialino 17. 30 9. 0 1. 65 Geant 4 Workshop Catania, October 4 -9 2004

Photon Compton cross section: statistical results NIST – XCOM Low. E Livermore NIST – XCOM Low. E Penelope NIST – XCOM Standard χ2 /ν p-value Be Al Si 0. 12 0. 07 1. 61 1 1 0. 09 0. 07 0. 18 0. 15 1 1 1 0. 53 0. 49 0. 60 0. 85 0. 86 0. 77 Fe Ge Ag Cs Au Pb U 0. 30 0. 13 0. 09 0. 14 0. 16 0. 23 0. 11 1 1 1 0. 69 1. 68 0. 65 0. 36 0. 41 1. 31 0. 13 0. 75 0. 07 0. 79 0. 97 0. 94 0. 21 1 0. 27 0. 38 0. 46 0. 62 1. 04 1. 18 0. 08 0. 99 0. 96 0. 92 0. 72 0. 41 0. 29 1 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Compton cross sections χ2/ν stability study (without the E=1 ke. V point) Ge χ2/ν stability study Si Pb Au Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photons: pair production cross section χ2/ν stability study Be Beryllium (not compatible with the NIST) deviations χ2/ν stability study Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photon pair production cross section: statistical results NIST – XCOM Low. E Livermore Low. E Penelope Standard Removing the 1 ke. V point χ2 /ν p-value Be Al Si 0. 05 0. 07 0. 09 1 1 1 8. 07 0. 83 0. 76 <0. 001 0. 69 7. 01 1. 07 0. 93 <0. 001 0. 39 0. 52 Fe Ge Ag Cs Au Pb U 0. 07 0. 04 0. 06 0. 24 0. 08 0. 11 0. 09 1 1 1 1 0. 32 0. 25 0. 15 0. 54 0. 09 0. 08 1. 18 0. 99 1 1 0. 89 1 1 1 0. 30 0. 18 0. 23 0. 30 0. 23 0. 22 0. 26 0. 99 1 1 0. 99 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photons: Rayleigh cross section Si Al χ2/ν stability study Ge Fe Au U Pb χ2/ν stability study deviations Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Photon Rayleigh cross section: statistical results NIST – XCOM Low. E Penelope χ2 /ν p-value Be Al Si 0. 27 1. 15 0. 68 0. 99 0. 97 0. 77 0. 17 24. 86 25. 08 1 <0. 001 Fe Ge Ag Au Pb U 0. 27 17. 97 1. 10 1. 90 8. 40 11. 31 1 <0. 001 0. 36 0. 05 <0. 001 11. 08 1. 06 1. 74 18. 99 22. 10 28. 19 <0. 001 0. 39 0. 08 <0. 001 Barbara Mascialino Geant 4 Workshop Test results are not consistent NIST – XCOM Low. E Livermore Catania, October 4 -9 2004

Critical discussion of this result • • The disagreement between NIST reference data and data coming from the recent library EPDL 97 (provided by Lawrence Livermore National Laboratory) within the range of energies between 1 ke. V and 1 Me. V has been already underlined and discussed in a recent paper by Zaidi*. In his paper Zaidi concluded that EPDL 97 is the most up-dated, complete and consistent data library available at the moment. For these features, it should be considered as a standard. * 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 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Electrons: stopping power χ2/ν stability study The three models are equivalent Strange effect (as a function of Z) NIST – ESTAR Low. E Livermore NIST – ESTAR Low. E Penelope BEST FIT NIST – ESTAR Standard BEST FIT Barbara Mascialino χ2/ν = -0. 032 + 0. 0074 Z R 2=0. 995 p<0. 0001 χ2/ν = -0. 046 + 0. 0073 Z R 2=0. 989 p<0. 0001 Geant 4 Workshop Catania, October 4 -9 2004

Electrons stopping power: statistical results NIST – ESTAR Low. E Livermore NIST – ESTAR Low. E Penelope NIST – ESTAR Standard χ2 /ν p-value Be Al Si 0. 03 0. 06 0. 07 1 1 1 0. 02 0. 05 0. 06 1 1 1 0. 02 0. 06 1 1 1 Fe Ge Cs Au Pb U 0. 15 0. 18 0. 36 0. 57 0. 58 0. 65 1 1 1 0. 96 0. 95 0. 91 0. 14 0. 17 0. 35 0. 56 0. 57 0. 64 1 1 1 0. 96 0. 92 0. 13 0. 15 0. 31 0. 54 0. 56 0. 64 1 1 1 0. 97 0. 92 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Electrons: CSDA range χ2/ν stability study Ag (to be explained) The three models are equivalent Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Electrons CSDA range: statistical results NIST – ESTAR Low. E Livermore NIST – ESTAR Low. E Penelope NIST – ESTAR Standard χ2 /ν p-value Be Al Si 0. 21 0. 05 0. 04 1 1 1 0. 24 0. 05 0. 04 1 1 1 0. 17 0. 04 1 1 1 Fe Ge Ag Cs Au Pb U 0. 02 0. 10 0. 009 0. 005 0. 004 1 1 1 1 0. 02 0. 01 1. 06 0. 004 0. 003 1 1 0. 39 1 1 0. 02 0. 008 0. 005 0. 004 0. 003 1 1 1 1 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Protons and alpha particles • Low. E Ziegler 85 • Low. E Ziegler 2000 • ICRU At low energies: free electron gas model At middle energies (~ Me. V): parametrisations At high energies: Bethe Bloch • Standard NIST database Statistical comparison cannot lead to a real physics validation, but we can only compare two different models (NIST – Ziegler) Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Protons: stopping power Low. E ICRU Standard Low. E Ziegler 85 l. OWe Ziegler 2000 NIST - PSTAR Barbara Mascialino χ2/ν stability study Geant 4 Workshop Catania, October 4 -9 2004

Protons stopping power: statistical results NIST – PSTAR Low. E ICRU 49 NIST – PSTAR Standard Low. E Ziegler 85 Low. E Ziegler 2000 χ2 /ν p χ2 /ν Be Al Si 0. 008 0. 02 0. 008 1 1 1 0. 41 0. 05 0. 41 1 Fe Ge Ag Au Pb U 0. 02 0. 12 0. 06 0. 08 0. 06 0. 10 1 1 1 0. 03 0. 53 0. 15 0. 27 0. 12 1. 28 1 1 1 0. 12 Barbara Mascialino χ2 /ν p 0. 66 0. 06 0. 81 0. 94 0. 01 1 0. 02 0. 79 0. 01 1 0. 03 0. 72 0. 10 0. 17 1. 28 1 0. 89 1 1 0. 21 0. 12 1 1 1 Geant 4 Workshop p 0. 02 0. 11 0. 04 0. 09 0. 05 0. 09 Catania, October 4 -9 2004

Protons: CSDA range χ2/ν stability study Low. E ICRU Standard Low. E Ziegler 85 Low. E Ziegler 2000 NIST - PSTAR Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Protons CSDA range: statistical results NIST – PSTAR Low. E ICRU 49 NIST – PSTAR Standard Low. E Ziegler 85 Low. E Ziegler 2000 χ2 /ν p χ2 /ν Be Al Si 0. 005 0. 03 0. 02 1 1 1 0. 11 0. 01 0. 29 1 1 1 Fe Ge Ag Au Pb U 0. 06 0. 13 0. 08 0. 09 0. 11 1 1 1 0. 20 0. 26 0. 34 0. 91 0. 21 1. 23 1 1 1 0. 62 1 0. 16 Barbara Mascialino Geant 4 Workshop p χ2 /ν p 1. 03 0. 01 0. 32 0. 41 0. 47 1 0. 27 0. 99 0. 23 1 1 1 0. 18 0. 27 0. 15 0. 47 0. 17 1. 18 1 1 0. 99 0. 21 1 1 1 0. 32 0. 24 0. 15 0. 14 0. 12 0. 13 Catania, October 4 -9 2004

Alpha particles: stopping power WORK IN PROGRESS Low. E ICRU Standard Low. E Ziegler 77 NIST - ASTAR Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Alpha particles: CSDA range WORK IN PROGRESS Low. E ICRU Standard Low. E Ziegler 77 NIST - ASTAR Barbara Mascialino Geant 4 Workshop Catania, 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. Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

SUMMARY: photons and electrons • 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 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

SUMMARY: protons and alpha particles • 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. Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004

Conclusions • Validation of all Geant 4 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 Geant 4 models (with respect to the NIST reference) • Mature project and results will be presented at IEEE-NSS – paper submitted for publication next month Barbara Mascialino Geant 4 Workshop Catania, 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 Barbara Mascialino Geant 4 Workshop Catania, October 4 -9 2004