from pathlib import Path
import numpy as np
_FILES = (
('electron', 'electrons.txt'),
('helium', 'helium_ions.txt'),
('mu-', 'negative_muons.txt'),
('pi-', 'negative_pions.txt'),
('neutron', 'neutrons.txt'),
('photon', 'photons.txt'),
('photon kerma', 'photons_kerma.txt'),
('mu+', 'positive_muons.txt'),
('pi+', 'positive_pions.txt'),
('positron', 'positrons.txt'),
('proton', 'protons.txt')
)
_DOSE_ICRP116 = {}
def _load_dose_icrp116():
"""Load effective dose tables from text files"""
for particle, filename in _FILES:
path = Path(__file__).parent / filename
data = np.loadtxt(path, skiprows=3)
data[:, 0] *= 1e6 # Change energies to eV
_DOSE_ICRP116[particle] = data
[docs]def dose_coefficients(particle, geometry='AP'):
"""Return effective dose conversion coefficients from ICRP-116
This function provides fluence (and air kerma) to effective dose conversion
coefficients for various types of external exposures based on values in
`ICRP Publication 116 <https://doi.org/10.1016/j.icrp.2011.10.001>`_.
Corrected values found in a correigendum are used rather than the values in
theoriginal report.
Parameters
----------
particle : {'neutron', 'photon', 'photon kerma', 'electron', 'positron'}
Incident particle
geometry : {'AP', 'PA', 'LLAT', 'RLAT', 'ROT', 'ISO'}
Irradiation geometry assumed. Refer to ICRP-116 (Section 3.2) for the
meaning of the options here.
Returns
-------
energy : numpy.ndarray
Energies at which dose conversion coefficients are given
dose_coeffs : numpy.ndarray
Effective dose coefficients in [pSv cm^2] at provided energies. For
'photon kerma', the coefficients are given in [Sv/Gy].
"""
if not _DOSE_ICRP116:
_load_dose_icrp116()
# Get all data for selected particle
data = _DOSE_ICRP116.get(particle)
if data is None:
raise ValueError("{} has no effective dose data".format(particle))
# Determine index for selected geometry
if particle in ('neutron', 'photon', 'proton', 'photon kerma'):
index = ('AP', 'PA', 'LLAT', 'RLAT', 'ROT', 'ISO').index(geometry)
else:
index = ('AP', 'PA', 'ISO').index(geometry)
# Pull out energy and dose from table
energy = data[:, 0].copy()
dose_coeffs = data[:, index + 1].copy()
return energy, dose_coeffs