CERN Accelerating science

Physics Lists EM constructors in Geant4 10.3


  • emstandard The default EM constructor is used in major part of reference Physics Lists (FTFP_BERT, FTF_BIC, QGSP_FTFP_BERT, QGSP_BIC, ...):
    • G4UrbanMscModel for multiple scattering of e+ and e- below 100 MeV;
    • G4WentzelVIModel for multiple scattering of combined with G4eCoulombScatteringModel for large angle scattering for muons, pions, kaions, protons, and anti-protons at all enegries, for e+ and e- above 100 MeV;
    • G4UrbanMscModel for all other chaged particles.

Option 1

Option 2

Option 3

  • emstandard_opt3 designed for any applications required higher accuracy of electrons, hadrons and ion tracking without magnetic field. It is used in extended electromagnetic examples and in the QGSP_BIC_EMY reference Physics List. The corresponding physics constructor includes following modifications:
    • G4UrbanMscModel for multiple scattering of all charged particles;
    • the option "fUseDistanceToBoundary" for multiple scattering of electrons and positrons;
    • accurate algorithm of sampling of lateral displacement is enabled;
    • increased number of bins in physics tables - 220 (84 bins by default), start all tables from 10 eV;
    • the parameter dRoverRange used in computation of step limit by the ionisation process is reduced with respect to the default value 0.2: 0.1 for alpha, He3, ions;
    • the parameter finalRange used in computation of step limit by the ionisation process is reduced with respect to the default value 1 mm: for e+,e- is 0.1 mm, for muons, pions, proton is 0.05 mm, for alpha and He3 0.01 mm, for ions 0.001 mm;
    • G4KleinNishinaModel is used for the Compton scattering simulation which include Doppler broading and allowing to simulate atomic deexcitation;
    • G4IonParametrisedLossModel is used for ion ionisation, this model is based on ICRU73 ion stopping data;
    • angular generator G4Generator2BS is used for bremsstrahlung;
    • G4RayleighScattering process is used with the default Livermore Rayleigh scattering model;
    • Fluorescence is enabled by default.
    • G4NuclearStopping process is used for alpha, He3, ions.

Option 4



Single scattering


Livermore with polarisation



DNA physics

Physics Lists per G4Region

High Enegry Processes

Physics Lists of Geant4 examples