Electromagnetic Standard Physics


The electromagnetic (EM) physics working group develops and maintains Geant4 sub-packages for simulation of electromagnetic interactions of charged particles, gammas and optical photons. The validity range of models is from 1 keV to 10 PeV. The physics approaches are optimal for high and medium energy applications and the set of these sub-packages is frequently called "Geant4 Standard EM Physics". The group is maintaining also components for reference Physics Lists and a number of extended examples.


Suspended Geant4 and Standard Electromagnetic Physics group members

Collaborators developing polarized processes (not Geant4 members)

Collaborators developing Coulomb scattering models (not Geant4 members)

Sub-packages and processes

Sub-directory Process or user interface SubType Comment
electromagnetic/highenergy G4AnnihiToMuPair 4 positron annihilation to muon pair
electromagnetic/highenergy G4GammaConversionToMuons 5 gamma conversion to muon pair
electromagnetic/highenergy G4eeToHadrons 4 positron annihilation to hadrons
electromagnetic/highenergy G4hhIonisation 2 heavy particle ionisation
electromagnetic/highenergy G4mplIonisation 2 classical magnetic monopole ionisation
electromagnetic/muons G4MuBremsstrahlung 3 muon bremsstrahlung
electromagnetic/muons G4MuIonisation 2 muon ionisation
electromagnetic/muons G4MuMultipleScattering 1 multiple scattering for muons
electromagnetic/muons G4MuPairProduction 8 e+e- pair production by muon
electromagnetic/muons G4ePairProduction 8 e+e- pair production by e+,e-
electromagnetic/polarisation G4PolarizedCompton 6 Compton scattering with circular polarization
electromagnetic/polarisation G4PolarizedGammaConversion 5 conversion of circular polarized gamma
electromagnetic/polarisation G4PolarizedPhotoElectricEffect 7 photo-electric effect for circular polarized gamma
electromagnetic/polarisation G4ePolarizedBremsstrahlung 3 bremsstrahlung of circular polarized e+ and e-
electromagnetic/polarisation G4ePolarizedIonisation 2 ionisation of circular polarized e+ and e-
electromagnetic/polarisation G4eplusPolarizedAnnihilation 4 annihilation of circular polarized positrons
electromagnetic/standard G4ComptonScattering 6 Compton scattering process
electromagnetic/standard G4CoulombScattering 1 single Coulomb scattering
electromagnetic/standard G4GammaConversion 5 gamma conversion to e+e- pair
electromagnetic/standard G4NuclearStopping 8 nuclear stopping of ions
electromagnetic/standard G4PhotoElectricEffect 7 photo-electric effect
electromagnetic/standard G4PolarizedComptonScattering 6 Compton scattering of linear polarized gamma
electromagnetic/standard G4eBremsstrahlung 3 electron and positron bremsstrahlung
electromagnetic/standard G4eIonisation 2 electron and positron ionisation
electromagnetic/standard G4eMultipleScattering 10 electron and positron multiple scattering
electromagnetic/standard G4ionIonisation 2 ionisation of ions with charge +2 and more
electromagnetic/standard G4hIonisation 2 ionisation of hadrons
electromagnetic/standard G4hMultipleScattering 10 multiple scattering of heavy changed particles
electromagnetic/xrays G4Cerenkov 21 Cerenkov radiation
electromagnetic/xrays G4Scintillation 22 scintillation process
electromagnetic/xrays G4SynchrotronRadiation 23 classical synchrotron radiation
electromagnetic/xrays G4SynchrotronRadiationInMat 23 synchrotron radiation in media
electromagnetic/xrays G4TransitionRadiation 24 transition radiation process
optical G4OpAbsorption 31 absorption of optical photons
optical G4OpBoundaryProcess 32 general boundary process for optical photons
optical G4OpRayleigh 33 Rayleigh scattering of optical photons
examples/extended/electromagnetic/TestEm7 G4ScreenedNuclearRecoil 1 single scattering for ions

Helper classes

Sub-directory Process or user interface Comment
electromagnetic/muons G4EnergyLossForExtrapolator Class for computation of energy loss and fluctuations by external codes
electromagnetic/utils G4EmCalculator interface to dE/dx and cross sections
electromagnetic/utils G4EmConfigurator adding models to Physics List
electromagnetic/utils G4EmProcessOptions C++ interface to EM options (before Geant4 10.1)
electromagnetic/utils G4EmParameters C++ interface to EM options (since Geant4 10.1)
electromagnetic/utils G4EmSaturation Computation of energy loss saturation (Birks effect)
materials G4NistManager Access to Geaant4 NIST DB and atomic properties


User support

The group is providing and maintaining extended examples:

  • electromagnetic;
  • exoticphysics;
  • medical;
  • optical;
  • polarisation.

We are suggesting our users to visit the HyperNews forum "emprocesses", that is the best way to exchange information.