Gamma contact dose rate computation fispact style

openmc/data/__init__.py

@@ -35,3 +35,4 @@
 from .function import *
 
 from .effective_dose.dose import dose_coefficients
+from .mass_energy_absorption import mu_en_coefficients

openmc/data/data.py

@@ -274,6 +274,7 @@
 # Unit conversions
 EV_PER_MEV = 1.0e6
 JOULE_PER_EV = 1.602176634e-19
+BARN_PER_CM_SQ = 1.0e24
 
 # Avogadro's constant
 AVOGADRO = 6.02214076e23

openmc/data/endf.py

@@ -59,7 +59,9 @@
              104: list(range(650, 700)),
              105: list(range(700, 750)),
              106: list(range(750, 800)),
-             107: list(range(800, 850))}
+             107: list(range(800, 850)),
+             501: [502, 504, 516, 522],
+             516: [515, 517]}
 
 ENDF_FLOAT_RE = re.compile(r'([\s\-\+]?\d*\.\d+)([\+\-]) ?(\d+)')
 

openmc/data/mass_energy_absorption.py

@@ -0,0 +1,93 @@
+import numpy as np
+
+import openmc.checkvalue as cv
+from openmc.data import EV_PER_MEV
+
+# Embedded NIST-126 data
+# Air (Dry Near Sea Level) — NIST Standard Reference Database 126 Table 4 (doi: 10.18434/T4D01F)
+# Columns: Energy (MeV), μen/ρ (cm^2/g)
+_NIST126_AIR = np.array(
+    [
+        [1.00000e-03, 3.599e03],
+        [1.50000e-03, 1.188e03],
+        [2.00000e-03, 5.262e02],
+        [3.00000e-03, 1.614e02],
+        [3.20290e-03, 1.330e02],
+        [3.20290e-03, 1.460e02],
+        [4.00000e-03, 7.636e01],
+        [5.00000e-03, 3.931e01],
+        [6.00000e-03, 2.270e01],
+        [8.00000e-03, 9.446e00],
+        [1.00000e-02, 4.742e00],
+        [1.50000e-02, 1.334e00],
+        [2.00000e-02, 5.389e-01],
+        [3.00000e-02, 1.537e-01],
+        [4.00000e-02, 6.833e-02],
+        [5.00000e-02, 4.098e-02],
+        [6.00000e-02, 3.041e-02],
+        [8.00000e-02, 2.407e-02],
+        [1.00000e-01, 2.325e-02],
+        [1.50000e-01, 2.496e-02],
+        [2.00000e-01, 2.672e-02],
+        [3.00000e-01, 2.872e-02],
+        [4.00000e-01, 2.949e-02],
+        [5.00000e-01, 2.966e-02],
+        [6.00000e-01, 2.953e-02],
+        [8.00000e-01, 2.882e-02],
+        [1.00000e00, 2.789e-02],
+        [1.25000e00, 2.666e-02],
+        [1.50000e00, 2.547e-02],
+        [2.00000e00, 2.345e-02],
+        [3.00000e00, 2.057e-02],
+        [4.00000e00, 1.870e-02],
+        [5.00000e00, 1.740e-02],
+        [6.00000e00, 1.647e-02],
+        [8.00000e00, 1.525e-02],
+        [1.00000e01, 1.450e-02],
+        [1.50000e01, 1.353e-02],
+        [2.00000e01, 1.311e-02],
+    ],
+    dtype=float,
+)
+
+# Registry of embedded tables: (data_source, material) -> ndarray
+# Table shape: (N, 2) with columns [Energy (MeV), μen/ρ (cm^2/g)]
+_MUEN_TABLES = {
+    ("nist126", "air"): _NIST126_AIR,
+}
+
+
+def mu_en_coefficients(
+    material: str, data_source: str = "nist126"
+) -> tuple[np.ndarray, np.ndarray]:
+    """Return tabulated mass energy-absorption coefficients.
+
+    Parameters
+    ----------
+    material : {'air'}
+        Material compound for which to load coefficients.
+    data_source : {'nist126'}
+        Source library.
+
+    Returns
+    -------
+    energy : numpy.ndarray
+        Energies [eV]
+    mu_en_coeffs : numpy.ndarray
+        Mass energy-absorption coefficients [cm^2/g]
+    """
+    cv.check_value("material", material, {"air"})
+    cv.check_value("data_source", data_source, {"nist126"})
+
+    key = (data_source, material)
+    if key not in _MUEN_TABLES:
+        available = sorted({m for (ds, m) in _MUEN_TABLES.keys() if ds == data_source})
+        raise ValueError(
+            f"'{material}' has no embedded μen/ρ table for data source {data_source}. "
+            f"Available materials for {data_source}: {available}"
+        )
+
+    data = _MUEN_TABLES[key]
+    energy = data[:, 0].copy() * EV_PER_MEV  # MeV -> eV
+    mu_en_coeffs = data[:, 1].copy()
+    return energy, mu_en_coeffs

openmc/data/photon.py

@@ -15,7 +15,7 @@
 from . import HDF5_VERSION, HDF5_VERSION_MAJOR
 from .ace import Table, get_metadata, get_table
 from .data import ATOMIC_SYMBOL, EV_PER_MEV
-from .endf import Evaluation, get_head_record, get_tab1_record, get_list_record
+from .endf import Evaluation, SUM_RULES, get_head_record, get_tab1_record, get_list_record
 from .function import Tabulated1D
 
 
@@ -487,6 +487,30 @@ def atomic_relaxation(self, atomic_relaxation):
     def name(self):
         return ATOMIC_SYMBOL[self.atomic_number]
 
+    def get_reaction_components(self, mt):
+        """Determine what reactions make up redundant reaction.
+
+        Parameters
+        ----------
+        mt : int
+            ENDF MT number of the reaction to find components of.
+
+        Returns
+        -------
+        mts : list of int
+            ENDF MT numbers of reactions that make up the redundant reaction and
+            have cross sections provided.
+
+        """
+        mts = []
+        if mt in SUM_RULES:
+            for mt_i in SUM_RULES[mt]:
+                mts += self.get_reaction_components(mt_i)
+        if mts:
+            return mts
+        else:
+            return [mt] if mt in self else []
+
     @classmethod
     def from_ace(cls, ace_or_filename):
         """Generate incident photon data from an ACE table