marley::GammaDiscreteExitChannel Class Reference

Gamma emission exit channel that leads to a discrete nuclear level in the final state More...

#include <ExitChannel.hh>

Inheritance diagram for marley::GammaDiscreteExitChannel:

Public Member Functions
	GammaDiscreteExitChannel (int pdgi, int qi, double Exi, int twoJi, marley::Parity Pi, double rho_i, marley::StructureDatabase &sdb, const marley::Level &flev)
virtual void	compute_total_width () final override
Public Member Functions inherited from marley::DiscreteExitChannel
	DiscreteExitChannel (const marley::Level &flev)
virtual void	do_decay (double &Ex, int &two_J, marley::Parity &Pi, const std::shared_ptr< HepMC3::GenParticle > &compound_nucleus, std::shared_ptr< HepMC3::GenParticle > &emitted_particle, std::shared_ptr< HepMC3::GenParticle > &residual_nucleus, int &qIon, marley::Generator &gen) const final override
	Simulates a nuclear decay into this channel.
const marley::Level &	get_final_level () const
	Get a const reference to the final-state nuclear level.
virtual bool	is_continuum () const final override
	Returns true if this channel accesses the particle-unbound continuum of nuclear levels or false otherwise.
Public Member Functions inherited from marley::ExitChannel
	ExitChannel ()=default
	ExitChannel (int pdgi, int qi, double Exi, int twoJi, marley::Parity Pi, double rho_i, marley::StructureDatabase &sdb)
double	width () const
	Get the total decay width into this channel (MeV)
Public Member Functions inherited from marley::GammaExitChannel
virtual bool	emits_fragment () const final override
	Returns true if this channel involves fragment emission or false if it involves gamma-ray emission.
virtual int	emitted_particle_pdg () const final override
	Returns the PDG code for the particle (gamma-ray or nuclear fragment) emitted by decays into this ExitChannel.
virtual int	final_nucleus_pdg () const final override
	Returns the PDG code for the final nucleus.

Additional Inherited Members
Static Public Member Functions inherited from marley::ExitChannel
template<typename It>
static marley::IteratorToPointerMember< It, double >	make_width_iterator (It it)
	Convert an iterator that points to an ExitChannel object into an iterator to the ExitChannel's width_ member variable.
Protected Member Functions inherited from marley::ExitChannel
virtual void	prepare_products (const std::shared_ptr< HepMC3::GenParticle > &compound_nucleus, std::shared_ptr< HepMC3::GenParticle > &emitted_particle, std::shared_ptr< HepMC3::GenParticle > &residual_nucleus, double Exf, int &qf, marley::Generator &gen) const
	Helper function that prepares Particle objects representing the products of the two-body decay.
Protected Member Functions inherited from marley::GammaExitChannel
double	gamma_energy (double Exf) const
marley::GammaStrengthFunctionModel::TransitionType	get_transition_type (int mpol, marley::Parity Pf) const
Protected Attributes inherited from marley::DiscreteExitChannel
const marley::Level &	final_level_
	Reference to the final-state nuclear level.
Protected Attributes inherited from marley::ExitChannel
double	Exi_
	Initial nuclear excitation energy \( E_x \) (MeV)
double	one_over_two_pi_rho_i_
int	pdgi_
	PDG code for the initial nucleus.
marley::Parity	Pi_
	Initial nuclear parity \( \Pi \).
int	qi_
marley::StructureDatabase *	sdb_
	StructureDatabase to use in calculations.
int	twoJi_
	Two times the initial nuclear spin \( J \).
double	width_
	Total decay width into this channel (MeV)

Detailed Description

Gamma emission exit channel that leads to a discrete nuclear level in the final state

Definition at line 381 of file ExitChannel.hh.

Constructor & Destructor Documentation

GammaDiscreteExitChannel()

marley::GammaDiscreteExitChannel::GammaDiscreteExitChannel ( int pdgi, int qi, double Exi, int twoJi, marley::Parity Pi, double rho_i, marley::StructureDatabase & sdb, const marley::Level & flev )

inline

Note

This line keeps old versions (4.9.3) of GCC happy

Definition at line 389 of file ExitChannel.hh.

                                 : ExitChannel( pdgi, qi, Exi, twoJi, Pi,
        rho_i, sdb ), DiscreteExitChannel( flev ), GammaExitChannel()
      {
        this->compute_total_width();
      }

References marley::DiscreteExitChannel::DiscreteExitChannel(), and compute_total_width().

Member Function Documentation

compute_total_width()

void marley::GammaDiscreteExitChannel::compute_total_width ( )

finaloverridevirtual

Helper function that initializes the width_ member variable upon construction

Implements marley::ExitChannel.

Definition at line 172 of file ExitChannel.cc.

                                                         {
 
  // Retrieve the gamma strength function model used to compute transmission
  // coefficients
  marley::GammaStrengthFunctionModel& gsfm
    = sdb_->get_gamma_strength_function_model( pdgi_ );
 
  // Get properties of the final nuclear level
  double Exf = final_level_.energy();
  int twoJf = final_level_.twoJ();
  marley::Parity Pf = final_level_.parity();
 
  // Initialize the total width to zero, just in case.
  width_ = 0.;
 
  if ( Exf >= Exi_ ) {
    issue_Exf_warning( Exf, Exi_ );
    return;
  }
 
  // Compute the energy of the emitted gamma-ray
  double E_gamma = this->gamma_energy( Exf );
 
  // Initialize the multipolarity for the start of the loop.
  // There is no monopole radiation, so the minimum allowed value is one.
  int start_mpol = std::max( 1, std::abs(twoJi_ - twoJf) / 2 );
  int end_mpol = ( twoJi_ + twoJf ) / 2;
 
  // Sum contributions to the decay width from different multipolarities
  for ( int mpol = start_mpol; mpol <= end_mpol; ++mpol ) {
 
    // Use the multipolarity and final-state nuclear parity to determine
    // whether the current partial width represents an electric or magnetic
    // transition
    TrType type = this->get_transition_type( mpol, Pf );
 
    double TXl = gsfm.transmission_coefficient( type, mpol, E_gamma );
 
    double term = one_over_two_pi_rho_i_ * TXl;
 
    // TODO: add caching of terms by Xl pair
 
    width_ += term;
  }
 
  // Guard against numerical issues by capping the total width at zero
  width_ = std::max( 0., width_ );
}

References marley::ExitChannel::Exi_, marley::DiscreteExitChannel::final_level_, marley::ExitChannel::one_over_two_pi_rho_i_, marley::ExitChannel::pdgi_, marley::ExitChannel::sdb_, marley::GammaStrengthFunctionModel::transmission_coefficient(), marley::ExitChannel::twoJi_, and marley::ExitChannel::width_.

Referenced by GammaDiscreteExitChannel().

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

• /home/sjg/Desktop/marley/include/marley/ExitChannel.hh
• /home/sjg/Desktop/marley/src/ExitChannel.cc