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. More...

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 (Rev Mod Phys 49,421(1977) and documented in section 6.5.2 (pair-production), and 10.2.1 and 10.2.4 (bremsstrahlung) of the Geant4 Physics Reference (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