EM physics constructors

Electromagnetic physics constructors were first published in [JA09], were extended in [VI11] and become stable in recent releases of Geant4 [JA16].

The default electromagnetic physics is built by the G4EmStandardPhysics constructor (see details in EM Opt0). It is implemented for the following particles: \( \gamma ,\ e^-,\ e^+,\ \mu ^-,\ \mu ^+,\ \tau ^-,\ \tau ^+,\) \(K^+,\ K^-,\ p,\ \Sigma ^+,\ \Sigma ^-,\ \Xi ^-,\ \Omega ^-,\) anti( \(\Sigma ^+,\ \Sigma ^-,\ \Xi ^-,\ \Omega ^-\)), \(d,\ t,\ ^3He,\ \alpha,\) anti( \(d,\ t,\ ^3He,\ \alpha \)), and G4GenericIon.

Several charmed mesons are also treated, \( D^+,\ D^-,\ D_s^+,\ D_s^-,\ \Lambda_c^+,\ \Sigma_c^+,\ \Sigma_c^{++},\ \Xi_c^+,\) anti(\(\Lambda _c^+,\ \Sigma _c^+,\ \Sigma _c^{++},\ \Xi_c^+\)), as well as two bottom mesons, \(B^+\) and \(B^-\).

Internal tables for energy loss, range and cross sections are built from 100 eV to 100 TeV. These limits are defined based on LHC experiments requirements. Upper limits of applicability of various electromagnetic processes are larger and are process dependent. For example, muon models are valid up to 1 PeV. In order to provide particle transport for all use-cases, the operational energy range goes down to zero but below 1 keV the accuracy of the default set of models is degraded substantially.

The Geant4 toolkit includes many alternative physics models, especially, for electromagnetic physics. There are several well established configurations recommended for different applications:

  • G4EmStandardPhysics_option1 EM Opt1 - extention name EMV;
  • G4EmStandardPhysics_option2 EM Opt2 - extention name EMX;
  • G4EmStandardPhysics_option3 EM Opt3 - extention name EMY;
  • G4EmStandardPhysics_option4 EM Opt4 - extention name EMZ;
  • G4EmLivermorePhysics EM Liv - extention name LIV;
  • G4EmPenelopePhysics EM Pen - extention name PEN;
  • G4EmStandardPhysics_GS EM GS - extention name _GS;
  • G4EmStandardPhysics_SS EM SS - extention name _SS;
  • G4EmStandardPhysics EM DNA.

Bibliography

[JA16]et al. J. Allison. Recent developments in geant4. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 835:186–225, nov 2016. URL: https://doi.org/10.1016/j.nima.2016.06.125, doi:10.1016/j.nima.2016.06.125.
[JA09]et al. J. Apostolakis. Geometry and physics of the geant4 toolkit for high and medium energy applications. Radiation Physics and Chemistry, 78(10):859–873, oct 2009. URL: https://doi.org/10.1016/j.radphyschem.2009.04.026, doi:10.1016/j.radphyschem.2009.04.026.
[VI11]et al. V. Ivanchenko. Recent improvements in geant4 electromagnetic physics models and interfaces. Progress in NUCLEAR SCIENCE and TECHNOLOGY, 2:898–903, oct 2011. URL: http://www.aesj.or.jp/publication/pnst002/data/898-903.pdf.