EM Opt1

This physics list uses “standard” Geant4 electromagnetic physics as built by the G4EmStandardPhysics_option1 constructor.

For each particle type several processes are implemented. Processes cover physics from 0 to 100 TeV for gamma, \(e^-\) and \(e^+\) and up to 1 PeV for muons. EM interactions of charged hadrons and ions cover the range 0 to 100 TeV. Though the operational energy range goes down to zero, below 1 keV accuracy of these models is substantially lower.

Photons: \(e^-/e^+\) pair production is implemented by the BetheHeitler model with the LPM effect at high energies and Compton scattering is implemented by the Klein-Nishina model. Photo-electric effect and Rayleigh scattering are both handled by the Livermore models. ApplyCuts option is use to cut out low-energy \(e^-\), produced by gamma processes.

Electrons and positrons: multiple Coulomb scattering is handled by the Urban model from 0 to 100 MeV and by the WentzelVI model from 100 MeV to 100 TeV, which is combined with the single Coulomb scattering model, which is applied for large angle scattering. Minimal step limitation is used for multiple scattering. Multiple scattering is combined with transportation in G4TransportationWithMsc process. Bremsstrahlung is implemented by the eBremSB model and the eBremLPM model which takes into account the LPM effect at high energies. Ionisation is modelled by the Moller-Bhabha formulation, and positron annihilation is implemented by the eplus2gg model.

Muons: multiple Coulomb scattering is handled by the WentzelVI model combined with the single scattering model at all energies, and by the eCoulombScattering model at all energies. Bremsstrahlung is handled by the MuBrem model. Ionisation is implemented by several models depending on energy and particle type. From 0 to 200 keV, the Bragg model is used for mu+ and the ICRU73Q0 parameterisation is used for mu-. Between 200 keV and 1 GeV the BetheBloch model is used for both \(\mu ^+\) and \(\mu ^-\), and from 1 GeV to 100 TeV, the MuBetheBloch model is used for both \(\mu ^+\) and \(\mu ^-\). The muPairProduction model handles e+/e- pair production caused by either \(\mu ^+\) or \(\mu ^-\).

Pions, kaons, protons and anti-protons: multiple Coulomb scattering is performed by the WentzelVI model and Coulomb scattering by the eCoulombScattering model. Bremsstrahlung is handled by hBrem model. \(e^-/e^+\) pair production by hadrons is implemented by the hPairProduction model. Ionisation is handled by several models depending on energy and particle type. For pions below 298 keV, Bragg model ionisation is used for \(\pi ^+\), and the ICRU73Q0 parameterisation is used for \(\pi ^-\). Above this energy BetheBloch ionisation is used. For kaons, the same ionisation models are used, but the change from low energy to high energy models occurs at 1.05 MeV. For protons, the Bragg model is used below 2 MeV and the BetheBloch above. For anti-protons ICRU73Q0 is used below 2 MeV and BetheBloch above.

Alpha and G4GenericIon: the same as in the default G4EmStandardPhysics constructor.