marley::BackshiftedFermiGasModel Class Reference

Implementation of the back-shifted Fermi gas nuclear level density model. More...

#include <BackshiftedFermiGasModel.hh>

Inheritance diagram for marley::BackshiftedFermiGasModel:

Public Member Functions
	BackshiftedFermiGasModel (int Z, int A)
virtual double	level_density (double Ex) override
virtual double	level_density (double Ex, int two_J) override
virtual double	level_density (double Ex, int two_J, marley::Parity Pi) override

Protected Member Functions
double	compute_sigma_F2 (double Ex, double a)
	Helper function used when evaluating the spin cutoff parameter.

Protected Attributes
int	A_
	mass number for this nuclide
double	a_tilde_
	asymptotic level density parameter (MeV -1)
double	Delta_BFM_
	excitation energy shift (MeV)
double	delta_W_
	shell correction energy (MeV)
double	gamma_
	damping parameter (MeV -1)
double	sigma_
	spin cut-off parameter
double	sigma_d_global_
	global fit for discrete-region spin cut-off parameter
double	Sn_
	neutron separation energy (MeV)
int	Z_
	atomic number for this nuclide

Detailed Description

Implementation of the back-shifted Fermi gas nuclear level density model.

Level density parameters used in this class are based on the global fits originally performed in A. J. Koning, et al., Nucl. Phys. A810 (2008) pp. 13-76. In addition to being used in MARLEY, this model has been adopted as one of the available options in the RIPL-3 data library and the TALYS nuclear code.

Constructor & Destructor Documentation

BackshiftedFermiGasModel()

marley::BackshiftedFermiGasModel::BackshiftedFermiGasModel	(	int	Z,
		int	A
	)

Create a back-shifted Fermi gas model object for a specific nuclide. This constructor will use global fits to initialize all level density parameters.

Parameters

Z	atomic number of the desired nuclide
A	mass number of the desired nuclide

Todo:

Add other constructors to the BackshiftedFermiGasModel class to allow the user to set the level density parameters based on local fits

Member Function Documentation

level_density() [1/3]

double marley::BackshiftedFermiGasModel::level_density ( double  Ex )

overridevirtual

Nuclear level density \( \rho(E_x) \) including all spins and parities.

Parameters

Ex	Excitation energy in MeV

Returns

Level density in MeV ^-1

Note

Calls to this function update the spin cut-off parameter sigma_

Todo:

Replace Ed here with database of local fits taken from RIPL-3 or TALYS

Todo:

Reconsider method used for handling spin cut-off parameter calculation for U <= Ed.

Implements marley::LevelDensityModel.

level_density() [2/3]

double marley::BackshiftedFermiGasModel::level_density ( double  Ex, int  two_J  )

overridevirtual

Level density \( \rho(E_x, J) \) for a specific nuclear spin.

Parameters

Ex	Excitation energy in MeV
two_J	Two times the nuclear spin

Returns

Level density in MeV ^-1

Implements marley::LevelDensityModel.

level_density() [3/3]

double marley::BackshiftedFermiGasModel::level_density ( double  Ex, int  two_J, marley::Parity  Pi  )

overridevirtual

Level density \( \rho(E_x, J, \Pi) \) for a specific nuclear spin and parity.

Parameters

Ex	Excitation energy in MeV
two_J	Two times the nuclear spin
Pi	The nuclear parity

Returns

Level density in MeV ^-1

The current implementation assumes parity equipartition.

Implements marley::LevelDensityModel.

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

• /Users/gardiner/marley/include/marley/BackshiftedFermiGasModel.hh
• /Users/gardiner/marley/src/BackshiftedFermiGasModel.cc