celeritas::TsaiUrbanDistribution Class Reference

Polar angular distribution for pair-production and bremsstrahlung processes. More...

#include <TsaiUrbanDistribution.hh>

Public Types
Type aliases
using	Energy = units::MevEnergy
using	Mass = units::MevMass
using	result_type = real_type

Public Member Functions
CELER_FUNCTION	TsaiUrbanDistribution (Energy energy, Mass mass)
	Construct from input data.
template<class Engine >
CELER_FUNCTION result_type	operator() (Engine &rng)
template<class Engine >
CELER_FUNCTION real_type	operator() (Engine &rng)
	Sample the cosine of the polar angle of the exiting gamma.

Detailed Description

Polar angular distribution for pair-production and bremsstrahlung processes.

For pair production, the polar angle of the electron (or positron) is defined with respect to the direction of the parent photon. The energy- angle distribution given by Tsai is quite complicated to sample and can be approximated by a density function suggested by Urban.

The angular distribution of the emitted photons is obtained from a simplified formula based on the Tsai cross-section, which is expected to become isotropic in the low energy limit.

Note

This performs the same sampling routine as in Geant4's ModifiedTsai class, based on derivation from [tsai-1974] and documented in section 6.5.2 (pair-production), and 10.2.1 and 10.2.4 (bremsstrahlung) of the Geant4 Physics Reference [g4prm] (release 10.6).

Member Function Documentation

operator()()

template<class Engine >

CELER_FUNCTION real_type celeritas::TsaiUrbanDistribution::operator()

(

Engine &

rng

)

Sample the cosine of the polar angle of the exiting gamma.

The z-axis is with respect to the direction of the parent particle.

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The documentation for this class was generated from the following file:

• TsaiUrbanDistribution.hh