electromagnetic physics validation l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Electromagnetic physics validation PowerPoint Presentation
Download Presentation
Electromagnetic physics validation

Loading in 2 Seconds...

play fullscreen
1 / 32

Electromagnetic physics validation - PowerPoint PPT Presentation


  • 123 Views
  • Uploaded on

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. The project.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Electromagnetic physics validation' - thane


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
electromagnetic physics validation

Electromagnetic physicsvalidation

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 4th-9th 2004

the project
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.

aim of the project
Aim of the project
  • Project for the validation of all Geant4 electromagnetic models against established references
  • The project s made-up by two parts:

GOODNESS-OF-FIT

TESTING

PHYSICAL TEST

Goodness-of-Fit statistical toolkit

Chi-squared stability study

test50

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

slide4

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 keV – 100 GeV

Testing activity has been automatised (thanks to SandraParlati and Koichi Murakami)

photons attenuation coefficient
Photons: attenuation coefficient

χ2/ν stability study

Be

Z dependency?

photon attenuation coefficient statistical results
Photon attenuation coefficient: statistical results

NIST – XCOM

LowE Livermore

NIST – XCOM

LowE Penelope

NIST – XCOM

Standard

photons photoelectric cross section
Photons: photoelectric cross section

χ2/ν stability study

Be

Cs

Z dependency?

photon photoelectric cross section statistical results
Photon photoelectric cross section: statistical results

NIST – XCOM

LowE Livermore

NIST – XCOM

LowE Penelope

NIST – XCOM

Standard

slide9

Photons: Compton cross section

The 1keV deviation effect is evident in both LowE Penelope and Standard packages

As an example, let us consider Ag:

photon compton cross section statistical results
Photon Compton cross section: statistical results

NIST – XCOM

LowE Livermore

NIST – XCOM

LowE Penelope

NIST – XCOM

Standard

compton cross sections 2 stability study
Compton cross sections χ2/ν stability study

(without the E=1 keV point)

Ge

χ2/ν stability study

Si

Pb

Au

slide12

Photons: pair production cross section

χ2/ν stability study

Be

(not compatible with the NIST)

Beryllium

deviations

χ2/ν stability study

photon pair production cross section statistical results
Photon pair production cross section: statistical results

NIST – XCOM

LowE Livermore

NIST – XCOM

LowE Penelope

NIST – XCOM

Standard

Removing the 1 keV point

slide14

Photons: Rayleigh cross section

χ2/ν stability study

Si

Al

Au

Ge

U

Pb

Fe

χ2/ν stability study

deviations

photon rayleigh cross section statistical results
Photon Rayleigh cross section: statistical results

NIST – XCOM

LowE Livermore

NIST – XCOM

LowE Penelope

Test results are not consistent

slide16

Critical discussion of this result

  • 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.

* 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

slide17

Electrons: stopping power

χ2/ν stability study

The three models

are equivalent

Strange effect

(as a function of Z)

NIST – ESTAR

LowE Livermore

BEST

FIT

χ2/ν = -0.032 + 0.0074 Z R2=0.995 p<0.0001

BEST

FIT

NIST – ESTAR

LowE Penelope

χ2/ν = -0.032 + 0.0074 Z R2=0.995 p<0.0001

BEST

FIT

NIST – ESTAR

Standard

χ2/ν = -0.046 + 0.0073 Z R2=0.989 p<0.0001

electrons stopping power statistical results
Electrons stopping power: statistical results

NIST – ESTAR

LowE Livermore

NIST – ESTAR

LowE Penelope

NIST – ESTAR

Standard

slide19

Electrons: CSDA range

χ2/ν stability study

Ag

(to be explained)

The three models

are equivalent

electrons csda range statistical results
Electrons CSDA range: statistical results

NIST – ESTAR

LowE Livermore

NIST – ESTAR

LowE Penelope

NIST – ESTAR

Standard

slide21

Protons and alpha particles

  • 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

NIST database

Statistical comparison cannot lead to a real physics validation, but we can only compare two different models (NIST – Ziegler)

protons stopping power
Protons: stopping power

χ2/ν stability study

LowE ICRU

Standard

LowE Ziegler 85

lOWe Ziegler 2000

NIST - PSTAR

protons stopping power statistical results
Protons stopping power: statistical results

NIST – PSTAR

LowE Ziegler2000

NIST – PSTAR

Standard

NIST – PSTAR

LowE ICRU49

NIST – PSTAR

LowE Ziegler85

protons csda range
Protons: CSDA range

χ2/ν stability study

LowE ICRU

Standard

LowE Ziegler 85

LowE Ziegler 2000

NIST - PSTAR

protons csda range statistical results
Protons CSDA range: statistical results

NIST – PSTAR

LowE Ziegler2000

NIST – PSTAR

Standard

NIST – PSTAR

LowE ICRU49

NIST – PSTAR

LowE Ziegler85

slide26

Alpha particles: stopping powerWORK IN PROGRESS

LowE ICRU

Standard

LowE Ziegler 77

NIST - ASTAR

slide27

Alpha particles: CSDA rangeWORK IN PROGRESS

LowE ICRU

Standard

LowE Ziegler 77

NIST - ASTAR

slide28

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 tablestreatment for both protons and alpha particles.

Systematic data analysis allowed to improve the physical models.

slide29

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
slide30

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.
conclusions
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
future perspectives
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