G3 to G4
Bremsstrahlung by muon

Total cross section, Mean free path, dE/dX table

• Geant3
  S(E,Z,Ecut): parameterisation from L.Urban (~60 parameters).
  dE/dX (E,Z,Tcut): - idem -
  Energy range: from ~1 GeV to 10 TeV
  

• Geant4
  S(E,Z,Ecut): starting from the (latest) theoretical differential cross section, the total cross section are computed by numerical integration.
  dE/dX (E,Z,Tcut): - idem -
  Energy range: from ~1 GeV to 1000 PeV
  

Final state

• Geant3
  Gamma energy sampled from Petrukhin-Shestakov cross section.
  Gamma angle sampled from an energy-angle distribution derived from Tsai formula.
  

• Geant4
  Photon energy sampled according the theoretical differential cross section.
  Photon and muon angles are sampled from an approximate (similar to Tsai) energy-angle distribution.