Photon interactions

Scattering

class KleinNishinaInteractor

Perform Compton scattering, neglecting atomic binding energy.

This is a model for the discrete Compton inelastic scattering process. Given an incident gamma, it adds a single secondary (electron) to the secondary stack and returns an interaction for the change to the incident gamma direction and energy. No cutoffs are performed for the incident energy or the exiting gamma energy. A secondary production cutoff is applied to the outgoing electron.

Note

This performs the same sampling routine as in Geant4’s G4KleinNishinaCompton, as documented in section 6.4.2 of the Geant4 Physics Reference (release 10.6).

class RayleighInteractor

Apply the Livermore model of Rayleigh scattering to photons.

Note

This performs the same sampling routine as in Geant4’s G4LivermoreRayleighModel class, as documented in section 6.2.2 of the Geant4 Physics Reference (release 10.6).

Photoelectric effect

class LivermorePEInteractor

Livermore model for the photoelectric effect.

A parameterization of the photoelectric cross sections in two different energy intervals, formulated as

$$

is used. The coefficients for this model are calculated by fitting the tabulated EPICS2014 subshell cross sections. The parameterized model applies above approximately 5 keV; below this limit (which depends on the atomic number) the tabulated cross sections are used. The angle of the emitted photoelectron is sampled from the Sauter-Gavrila distribution.

Note

This performs the same sampling routine as in Geant4’s G4LivermorePhotoElectricModel class, as documented in section 6.3.5 of the Geant4 Physics Reference (release 10.6).

class AtomicRelaxation

Simulate particle emission from atomic deexcitation.

The EADL radiative and non-radiative transition data is used to simulate the emission of fluorescence photons and (optionally) Auger electrons given an initial shell vacancy created by a primary process.

Livermore photoelectric cross sections are calculated on the fly.

class LivermorePEMicroXsCalculator

Calculate photoelectric effect cross sections using the Livermore data.