A radionuclide spectrum. More...

#include <egs_radionuclide_source.h>

Public Member Functions
	EGS_RadionuclideSpectrum (const string nuclide, const string ensdf_file, const EGS_Float relativeActivity, const string relaxType, const string outputBetaSpectra, const bool scoreAlphasLocally, const bool allowMultiTransition)
	Construct a radionuclide spectrum.

	~EGS_RadionuclideSpectrum ()
	Destructor.

EGS_Float	maxEnergy () const
	Returns the maximum energy that may be emitted. More...

int	getCharge () const
	Get the charge of the most recent emission.

double	getTime () const
	Get the emission time of the most recent emission.

EGS_I64	getShowerIndex () const
	Get the shower index of the most recent emission.

EGS_Float	getEdep () const
	Get energy that should be deposited locally from relaxations/alphas.

EGS_Float	getSpectrumWeight () const
	Get the relative weight assigned to this spectrum.

void	setSpectrumWeight (EGS_Float newWeight)
	Set the relative weight assigned to this spectrum.

unsigned int	getEmissionType () const
	Get the emission type of the most recent source particle. More...

void	printSampledEmissions ()
	Print the sampled emission intensities.

EGS_Ensdf *	getRadionuclideEnsdf ()

bool	storeState (ostream &data) const

bool	setState (istream &data)

void	resetCounter ()

EGS_Float	sample (EGS_RandomGenerator *rndm)
	Sample an event from the spectrum, returns the energy of the emitted particle.

Detailed Description

A radionuclide spectrum.

Generates spectra for radionuclide emissions. This spectrum type is used by EGS_RadionuclideSource. Currently spectrum data is obtained from ENSDF format data files using EGS_Ensdf. These files can be found in $HEN_HOUSE/spectra/lnhb/ensdf/. For more information about the ENSDF format and how it is processed, see EGS_Ensdf.

It is defined using the following input

:start spectrum:
    type            = radionuclide
    nuclide         = name of the nuclide (e.g. Sr-90), used to look up the
                        ensdf file as $HEN_HOUSE/spectra/lnhb/ensdf/{nuclide}.ensdf
                        if ensdf file not provided below
    ensdf file      = [optional] path to a spectrum file in ensdf format,
                        including extension
    relative activity = [optional] the relative activity (sampling
                        probability) for this nuclide in a mixture
    atomic relaxations = [optional, default=eadl] eadl, ensdf or off
                                 By default, 'eadl' relaxations use the EGSnrc
                                 algorithm for emission correlated with
                                 disintegration events. Alternatively, 'ensdf'
                                 relaxations statistically sample fluorescent
                                 photons and Auger emission using comments
                                 in the ensdf file. Turning this option off
                                 disables all relaxations resulting from
                                 radionuclide disintegration events.
    output beta spectra = [optional, default=no] yes or no
                            whether or not to output beta spectra to files.
                            Files will be named based on the nuclide and
                            maximum energy of the beta decay:
                            {nuclide}_{energy}.spec
    alpha scoring       = [optional, default=none] none or local
                            Whether or not to deposit alpha particles locally.
                            Since alpha particles are not transported in EGSnrc,
                            there are only two options. Either discard the alpha
                            particles and their energy completely, or deposit
                            the energy immediately after creation in the
                            local region.
    extra transition approximation = [optional, default=off] off or on
                            If the intensity away from a level in a radionuclide
                            daughter is larger than the intensity feeding the
                            level (e.g. decays to that level), then additional
                            transitions away from that level will be sampled if
                            this approximation is on.
                            They will not be correlated with decays, but the
                            spectrum will produce emission rates to match both
                            the decay intensities and the internal transition
                            intensities from the ensdf file.
:stop spectrum:
:start spectrum:
    type                = radionuclide
    nuclide             = name of next nuclide in mixture (e.g. Y-90)
    relative activity   = ...
:stop spectrum:

The source spectrum determines which emission type occurs, and proceeds to sample the emission parameters. In some cases, no particle is emitted - this state is signaled by returning zero. The spectrum either models a disintegration, an internal transition or the emission of Auger/fluorescence from relaxations.

Beta- and beta+ disintegrations emit an electron or positron, respectively. The energies of beta particles are sampled from spectra generated by EGS_RadionuclideBetaSpectrum. Electron capture events are also sampled and result in shell vacancies / relaxations, but neutrinos are not modeled. In this case, EGS_RadionuclideSpectrum returns zero. Disintegrations may set the energy level of the daughter nuclide to an excited state, leading to the emission of transition photons, conversion electrons and relaxation emissions on subsequent calls to sample().
Alpha disintegrations may also set the energy level of the daughter to an excited state. Alpha particles themselves are not modeled, so a zero energy particle is returned. Use the 'alpha scoring = local' option to force alpha particles to deposit energy in the same region as their creation. By default, no energy is deposited and the alpha particles are discarded immediately.
Internal transitions are sampled following a disintegration if the daughter nuclide is in an excited state. The energy level of the daughter is then reset according to the internal transition that took place. Note that there are cases where a transition is not guaranteed. In such a case, the daughter level is set to zero and zero energy is returned from sample(). There are also cases where multiple transitions occur after a single disintegration, if the 'extra transition approximation' option is set to 'on'. Internal transitions may also result in conversion electrons and relaxation emissions. Internal pair production is currently modelled in the sampling routine, but no particles are produced.
Relaxations that result in X-Ray fluorescence and Auger emissions return photons or electrons until the cascade is complete. Note that X-Ray and Auger emissions are not disintegrations so are not counted in the fluence (or the ishower parameter). These particles are assigned the same shower index as the most recent disintegration and the same time of emission as the most recent disintegration or internal transition, whichever was last. Relaxations may result in local energy depositions - this can be obtained using getEdep() .

The printSampledEmissions() function is provided for evaluating how the decay emissions actually end up sampled by the source. The function prints the signature energy and emission intensity of each emission type for the radionuclide. The intensity is the ratio of the number of emissions of that type sampled and the total fluence, multiplied by 100. This provides units comparable to intensities in ensdf files (intensity per 100 disintegrations). To add this output following the simulation, it will be necessary to edit runSimulation() in the application (e.g. in egs_chamber.cpp). At the end of runSimulation(), add a line such as source->printSampledEmissions();.

Definition at line 645 of file egs_radionuclide_source.h.

Member Function Documentation

◆ maxEnergy()

EGS_Float EGS_RadionuclideSpectrum::maxEnergy ( ) const

Returns the maximum energy that may be emitted.

Returns the maximum energy expected from the radionuclide. If correlated relaxations are turned on (e.g. eadl relaxations), note that they are not considered in this. Relaxation emissions from the ENSDF file are considered.

Definition at line 670 of file egs_radionuclide_source.h.

◆ getEmissionType()

unsigned int EGS_RadionuclideSpectrum::getEmissionType ( ) const

Get the emission type of the most recent source particle.

0: No event occurred 1: Atomic relaxation particle (correlated with decay) 2: Internal transition gamma 3: Conversion electron 4: Electron capture 5: Beta+ decay 6: Beta- decay 7: Alpha decay 8: Metastable decay 9: X-Ray (uncorrelated, from ENSDF) 10: Auger electron (uncorrelated, from ENSDF) 11: Uncorrelated internal transition gamma 12: Uncorrelated conversion electron 13: Internal pair production 14: Uncorrelated internal pair production

Definition at line 722 of file egs_radionuclide_source.h.

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

/home/rwtownson/EGSnrc/HEN_HOUSE/egs++/sources/egs_radionuclide_source/egs_radionuclide_source.h
/home/rwtownson/EGSnrc/HEN_HOUSE/egs++/sources/egs_radionuclide_source/egs_radionuclide_source.cpp

Public Member Functions

Detailed Description

Member Function Documentation

◆ maxEnergy()

◆ getEmissionType()