ENDF File Support – `pyne.endf`¶

Module for parsing and manipulating data from ENDF evaluations. Currently, it only can read several MTs from File 1, but with time it will be expanded to include the entire ENDF format.

All the classes and functions in this module are based on document ENDF-102 titled “Data Formats and Procedures for the Evaluated Nuclear Data File ENDF-6”. The latest version from June 2009 can be found at http://www-nds.iaea.org/ndspub/documents/endf/endf102/endf102.pdf

For more information on the Evaluation class, contact Paul Romano <paul.k.romano@gmail.com>. For more information on the Library class, contact John Xia <john.danger.xia@gmail.com>.

class pyne.endf.AdlerAdler(emin, emax, nro, naps)¶

Adler-Adler resolved resonance formalism data. This is identified by LRF=4 in the ENDF-6 format.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

spinfloat: Spin of the target nucleus
scattering_radius_indfloat: Scattering radius in units of 10^-12 cm
LIfloat: Flag indicating the kind of parameters
AT, BTndarray: Background constants for the total cross section
AC, BCndarray: Background constants for the radiative cross section
AF, BFndarray: Background constants for the fission cross section
resonanceslist of AdlerResonance: List of resonances defined by Adler-Adler parameters

read(self, ev)¶

Read Adler-Adler resonance data from an ENDF evaluation.

Parameters

evEvaluation: ENDF evaluation positioned at the start of a resonance range subsection

class pyne.endf.ArbitraryTabulated(energy, pdf)¶

Arbitrary tabulated function given in ENDF MF=5, LF=1 represented as

\[f(E \rightarrow E') = g(E \rightarrow E')\]

Attributes

energyndarray: Array of incident neutron energies
pdflist of Tab1: Tabulated outgoing energy distribution probability density functions

class pyne.endf.EnergyDistribution¶

Energy distribution from ENDF MF=5.

Attributes

lfint: Flag specifying energy distribution.

class pyne.endf.Evaluation(filename_or_handle, verbose=True)¶

ENDF material evaluation with multiple files/sections

The Evaluation class provides a means to parse data from an ENDF-6 format file and access it as stored internal Python objects. A summary of the parsing capabilities is as follows:

MF	MT	Description	Complete
1	451	Descriptive data and directory	Yes
1	452	Number of neutrons per fission	Yes
1	455	Delayed neutron data	Yes
1	456	Number of prompt neutrons per fission	Yes
1	458	Components of fission energy release	Yes
1	460	Delayed photon data	Yes
2	151	Resonance parameters	Yes
3		Reaction cross sections	Yes
4		Angular distributions	Yes
5		Energy distributions	Yes
6		Product energy-angle distributions	Yes
7	2	Thermal elastic scattering	Yes
7	4	Thermal inelastic scattering	Yes
8	454	Independent fission yields	Yes
8	457	Radioactive decay data	Yes
8	459	Cumulative fission yields	Yes
8		Radioactive nuclide production	Yes
9		Multiplicities of radioactive products	Yes
10		Production cross sections for radionuclides	Yes
12		Photon production yield data	Yes
13		Photon production cross sections	Yes
14		Photon angular distributions	Yes
15		Continuous photon energy spectra	Yes
23		Photon and electron cross sections	Yes
26		Secondary distributions for electro-atomic data	Yes
27		Atomic form factors	Yes
28	533	Atomic relaxation data	Yes
30	1	Directory and correspondance table	No
30	2	Covariance matrix	No
30		Sensitivities	No
31		Covariances of fission	No
32		Covariances of resonance parameters	No
33		Covariances of neutron cross sections	No
34		Covariances for angular distributions	No
35		Covariances for energy distributions	No
40		Covariances for radionuclide production	No

Attributes

atomic_relaxationdict: Dictionary containing atomic relaxation data from MF=28, MT=533. If the evaluation is not an atomic relaxation sublibrary, the dictionary is empty.
decaydict: Dictionary containing decay data from MF=8. If the evaluation is not from a decay sublibrary, the dictionary is empty.
fissiondict: Dictionary containing fission-related data, such as neutrons release from fission (MF=1, MT=452,455,456), components of energy release (MF=1, MT=458), delayed photons from fission (MF=1, MT=460), and cumulative/independent fission yields (MF=8, MT=454,459).
infodict: Miscallaneous information about the evaluation.
targetdict: Information about the target material, such as its mass, isomeric state, whether it’s stable, and whether it’s fissionable.
projectiledict: Information about the projectile such as its mass.
reaction_listlist of 4-tuples: List of sections in the evaluation. The entries of the tuples are the file (MF), section (MT), number of records (NC), and modification indicator (MOD).
reactionscollections.OrderedDict: Dictionary whose keys are MT numbers and values are Reaction instances.
resonancesdict: Resolved resonance data from MF=2, MT=151.
thermal_elasticdict: Coherent and/or incoherent thermal elastic data from MF=7, MT=2.
thermal_inelasticdict: Incoherent thermal inelastic data from MF=7, MT=4.

read(self, reactions=None, skip_mf=[], skip_mt=[])¶

Reads reactions from the ENDF file of the Evaluation object. If no arguments are provided, this method will read all the reactions in the file. A single reaction can be read if provided.

Parameters

reactionstuple or list of tuple, optional: A single reaction in the following format: (MF, MT)
skip_mflist of int, optional: Files (MF) which should not be read
skip_mtlist of int, optional: Reactions (MT) which should not be read

class pyne.endf.Evaporation(theta, u)¶

Evaporation spectrum given in ENDF MF=5, LF=9 represented as

\[f(E \rightarrow E') = \frac{E'}{I} e^{-E'/\theta(E)}\]

Attributes

thetaTab1: Tabulated function of incident neutron energy
ufloat: Constant introduced to define the proper upper limit for the final particle energy such that \(0 \le E' \le E - U\)

class pyne.endf.GeneralEvaporation(theta, g, u)¶

General evaporation spectrum given in ENDF MF=5, LF=5 represented as

\[f(E \rightarrow E') = g(E'/\theta(E))\]

Attributes

thetaTab1: Tabulated function of incident neutron energy \(E\)
gTab1: Tabulated function of \(x = E'/\theta(E)\)
ufloat: Constant introduced to define the proper upper limit for the final particle energy such that \(0 \le E' \le E - U\)

class pyne.endf.Library(fh)¶

A class for a file which contains multiple ENDF evaluations.

get_rx(self, nuc, mf, mt, lines=0)¶

Grab the data from one reaction type.

Parameters

nucint: id form of material to read from.
mfint: ENDF file number (MF).
mtint: ENDF reaction number (MT).
linesint: Number of lines to read from this reaction, starting from the top. Default value is 0, which reads in the entire reaction.

Returns

dataNumPy array: Contains the reaction data in an Nx6 array.

get_xs(self, nuc, mt, nuc_i=None)¶

Grab cross-section data.

Parameters

nuc: int: id of nuclide to read.
mt: int: ENDF reaction number to read.
nuc_i: int: id of isotope to read. Defaults to nuc.

Returns

tuple: Returns a tuple with xs data in tuple[0] and flags in tuple[1].

integrate_tab_range(self, intscheme, e_int, xs, low=None, high=None)¶

Integrates across one tabulation range.

Parameters

intschemeint or float: The interpolation scheme used in this range.
e_intarray: The energies at which we have xs data.
xsarray: The xs data corresponding to e_int.
low, highfloat: Lower and upper bounds within the tabulation range to start/stop at.

Returns

sigma_gfloat: The group xs.

load(self)¶

Read the ENDF file into a NumPy array.

Returns

datanp.array, 1d, float64: Returns a 1d float64 NumPy array.

class pyne.endf.MadlandNix(efl, efh, tm)¶

Energy-dependent fission neutron spectrum (Madland and Nix) given in ENDF MF=5, LF=12 represented as

\[f(E \rightarrow E') = \frac{1}{2} [ g(E', E_F(L)) + g(E', E_F(H))]\]

where

\[\begin{split}g(E',E_F) = \frac{1}{3\sqrt{E_F T_M}} \left [ u_2^{3/2} E_1 (u_2) - u_1^{3/2} E_1 (u_1) + \gamma \left ( \frac{3}{2}, u_2 \right ) - \gamma \left ( \frac{3}{2}, u_1 \right ) \right ] \\ u_1 = \left ( \sqrt{E'} - \sqrt{E_F} \right )^2 / T_M \\ u_2 = \left ( \sqrt{E'} + \sqrt{E_F} \right )^2 / T_M.\end{split}\]

Attributes

efl, efhfloat: Constants which represent the average kinetic energy per nucleon of the fission fragment (efl = light, efh = heavy)
tmTab1: Parameter tabulated as a function of incident neutron energy

class pyne.endf.Maxwellian(theta, u)¶

Simple Maxwellian fission spectrum given in ENDF MF=5, LF=7 represented as

\[f(E \rightarrow E') = \frac{\sqrt{E'}}{I} e^{-E'/\theta(E)}\]

Attributes

thetaTab1: Tabulated function of incident neutron energy
ufloat: Constant introduced to define the proper upper limit for the final particle energy such that \(0 \le E' \le E - U\)

class pyne.endf.MultiLevelBreitWigner(emin, emax, nro, naps)¶

Multi-level Breit-Wigner resolved resonance formalism data. This is identified by LRF=2 in the ENDF-6 format.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

spinfloat: Spin of the target nucleus
scattering_radius_indfloat: Scattering radius in units of 10^-12 cm
resonanceslist of Resonance: List of resolved resonances
l_valuesndarray of int: Neutron orbital angular momentum values
qndarray of float: Q-value to be added to incident particle’s center-of-mass energy to determine the channel energy for use in the penetrability factor. Given as a function of the l-value.
competitivendarray of bool: Whether a competitive width is given for each l-value.

read(self, ev)¶

Read multi-level Breit-Wigner resonance data from an ENDF evaluation.

Parameters

evEvaluation: ENDF evaluation positioned at the start of a resonance range subsection

class pyne.endf.RMatrixLimited(emin, emax, nro, naps)¶

R-Matrix Limited resolved resonance formalism data. This is identified by LRF=7 in the ENDF-6 format.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

IFGint: Flag indicating whether channel widths in eV or reduced-width amplitudes in eV^1/2 are given
KRMint: Flag to specify which formulae for the R-matrix are to be used
particle_pairslist of dict: List of particle pairs. Each particle pair is represented by a dictionary that contains the mass, atomic number, spin, and parity of each particle as well as other characteristics.
spin_groupslist of dict: List of spin groups. Each spin group is characterized by channels, resonance energies, and resonance widths.

read(self, ev)¶

Read R-Matrix limited resonance data from an ENDF evaluation.

Parameters

evEvaluation: ENDF evaluation positioned at the start of a resonance range subsection

class pyne.endf.Reaction(mt)¶

Data for a single reaction including its cross section and secondary angle/energy distribution.

Parameters

mtint: The MT number from the ENDF file.

Attributes

angular_distributionAngularDistribution: Angular distribution represented as a tabulated function or as moments of a Legendre polynomial expansion from MF=4.
complex_breakup_flagint: Complex breakup flag.
xsTab1: Tabulated cross section as a function of incident energy from MF=3.
energy_distributionlist of EnergyDistribution: List of partial energy distributions for the reaction from MF=5.
fileslist of int: List of files (MF) that have been read for this reaction
MTint: The MT number from the ENDF file.
multiplicitiesdict: Multiplicities for production of radioactive nuclides as given in MF=9.
product_distributionlist of dict: Secondary energy or correlated energy-angle distribution from MF=6.
productiondict: Cross sections for production of radioactive nuclides as given in MF=10.
Q_mass_differencefloat: Mass difference Q value in eV
Q_reactionfloat: Reaction Q value in eV
radionuclide_productionlist of dict: List of radioactive nuclides produced as given in MF=8.
reference_frame{‘laboratory’, ‘center-of-mass’, ‘light-heavy’}: Indicates what reference frame is used for outgoing energies and angles. Only relevant for product energy-angle distributions read in MF=6.
subshell_binding_energyfloat: Subshell binding energy in eV as given in MF=23. Only relevant for photoelectric subshell ionization reactions in a photo-atomic sublibrary.
fluorescence_yieldfloat: Fluorescence yield (eV/photoionization) as given in MF=23. Only relevant for photoelectric subshell ionization reactions in a photo-atomic sublibrary.
productslist of dict: Secondary photon and electron distributions for electro-atomic reactions as given in MF=26.
scattering_factorTab1: Coherent or incoherent form factor as given in MF=27.
anomalous_scattering_imaginaryTab1: Imaginary component of the anomalous scattering factor as given in MF=27.
anomalous_scattering_realTab1: Real component of the anomalous scattering factor as given in MF=27.

class pyne.endf.ReichMoore(emin, emax, nro, naps)¶

Reich-Moore resolved resonance formalism data. This is identified by LRF=3 in the ENDF-6 format.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

resonancesdict: Dictionary whose keys are (l, J) pairs and values are instances are lists of Resonance instances.
spinfloat: Spin of the target nucleus
scattering_radius_indfloat: Energy-independent scattering radius in units of 10^-12 cm
scattering_radiusTab1: Scattering radius in units of 10^-12 cm as a function of energy
LADint: Indicate whether parameters can be used to compute angular distributions
NLSCint: Number of l-values which must be used to converge the calculation
aplndarray of float: l-dependent scattering radius
l_valuesndarray of int: Neutron orbital angular momentum values

read(self, ev)¶

Read Reich-Moore resonance data from an ENDF evaluation.

Parameters

evEvaluation: ENDF evaluation positioned at the start of a resonance range subsection

class pyne.endf.ResonanceRange(emin, emax, nro, naps)¶

Resolved resonance formalism data as given in MF=2, MT=151.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

energy_minfloat: Minimum energy of the resolved resonance range in eV
energy_maxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

class pyne.endf.ScatteringRadius(emin, emax, nro, naps)¶

Energy range with no resonances and only a scattering radius.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

class pyne.endf.SingleLevelBreitWigner(emin, emax, nro, naps)¶

Single-level Breit-Wigner resolved resonance formalism data. This is identified by LRF=1 in the ENDF-6 format.

Parameters

eminfloat: Minimum energy of the resolved resonance range in eV
emaxfloat: Maximum energy of the resolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

class pyne.endf.Tab1(x, y, nbt, interp)¶

A one-dimensional tabulated function.

Parameters

xarray_like: Independent variable
yarray_like: Dependent variable
nbtarray_like of int: Breakpoints for interpolation regions
interparray_like of int: Interpolation scheme identification number, e.g., 3 means y is linear in ln(x).

classmethod from_file(fh)¶

Create Tab1 object using open file handle.

Parameters

fhfile: File open and positioned to the start of a TAB1 record.

integral(self)¶

Integral of the tabulated function over its tabulated range.

Returns

ndarray: Array of same length as the tabulated data that represents partial integrals from the bottom of the range to each tabulated point.

class pyne.endf.Unresolved(emin, emax, nro, naps)¶

Unresolved resonance parameters as identified by LRU=2 in MF=2.

Parameters

eminfloat: Minimum energy of the unresolved resonance range in eV
emaxfloat: Maximum energy of the unresolved resonance range in eV
nroint: Flag designating energy-dependence of scattering radius (NRO). A value of 0 indicates it is energy-independent, a value of 1 indicates it is energy-dependent.
napsint: Flag controlling use of the channel and scattering radius (NAPS)

Attributes

scattering_radiusfloat: Scattering radius in units of 10^-12 cm
LSSFint: Flag governing interpretation of file 3 cross sections
spinfloat: Spin of the target nucleus
l_valuesndarray of int: Neutron orbital angular momentum values
parametersdict of dict: Dictionary whose keys are l-values and whose values are dictionaries containing unresolved resonance parameters

read(self, ev)¶

Read unresolved resonance data from an ENDF evaluation.

Parameters

evEvaluation: ENDF evaluation positioned at the start of a resonance range subsection

class pyne.endf.Watt(a, b, u)¶

Energy-dependent Watt spectrum given in ENDF MF=5, LF=11 represented as

\[f(E \rightarrow E') = \frac{e^{-E'/a}}{I} \sinh \left ( \sqrt{bE'} \right )\]

Attributes

a, bTab1: Energy-dependent parameters tabulated as function of incident neutron energy
ufloat: Constant introduced to define the proper upper limit for the final particle energy such that \(0 \le E' \le E - U\)

pyne.endf.at_end_of_tape()¶

Indicate whether file is positioned at the end of an ENDF tape.

Parameters

ffile_like: File to check

Returns

bool: Whether the file is at the end of the ENDF tape

pyne.endf.seek_file_end()¶

Position the file at the end of the ENDF file (MF) currently being read.

Parameters

ffile_like: File to position

pyne.endf.seek_material_end()¶

Position the file at the end of the ENDF material (MAT) currently being read.

Parameters

ffile_like: File to position

pyne.endf.seek_section_end()¶

Position the file at the end of the ENDF section (MT) currently being read.

Parameters

ffile_like: File to position

ENDF File Support – pyne.endf¶

ENDF File Support – `pyne.endf`¶