celeritas::BetheBlochEnergyDistribution Class Reference

Sample the energy of the delta ray for muon or hadron ionization. More...

#include <BetheBlochEnergyDistribution.hh>

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

Public Member Functions
CELER_FUNCTION	BetheBlochEnergyDistribution (ParticleTrackView const &particle, Energy electron_cutoff, Mass electron_mass)
	Construct with incident and exiting particle data.
template<class Engine >
CELER_FUNCTION Energy	operator() (Engine &rng)
CELER_FUNCTION Energy	min_secondary_energy () const
	Minimum energy of the secondary electron [MeV].
CELER_FUNCTION Energy	max_secondary_energy () const
	Maximum energy of the secondary electron [MeV].
template<class Engine >
CELER_FUNCTION auto	operator() (Engine &rng) -> Energy
	Sample secondary electron energy.

Detailed Description

Sample the energy of the delta ray for muon or hadron ionization.

This samples the energy according to the Bethe-Bloch model, as described in [g4prm] (release 11.2, section 12.1.5). The Bethe-Bloch differential cross section can be written as

\[ \difd{\sigma}{T} = 2\pi r_e^2 mc^2 Z \frac{z_p^2}{\beta^2}\frac{1}{T^2} \left[1 - \beta^2 \frac{T}{T_{max}} + s \frac{T^2}{2E^2} \right] \]

and factorized as

\[ \difd{\sigma}{T} = C f(T) g(T) \]

with \( T \in [T_{cut}, T_{max}] \), where \( f(T) = \frac{1}{T^2} \), \( g(T) = 1 - \beta^2 \frac{T}{T_max} + s \frac{T^2}{2 E^2} \), \( T \) is the kinetic energy of the electron, \( E \) is the total energy of the incident particle, and \( s \) is 0 for spinless particles and 1 otherwise. The energy is sampled from \( f(T) \) and accepted with probability \( g(T) \).

Member Function Documentation

operator()()

template<class Engine >

CELER_FUNCTION auto celeritas::BetheBlochEnergyDistribution::operator()

(

Engine &

rng

)

-> Energy

Sample secondary electron energy.

Todo:

Adjust rejection functions if particle has positive spin

Todo:

For hadrons, suppress high energy delta ray production with the projectile form factor

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

• BetheBlochEnergyDistribution.hh