pub fn natural_abundance(z: u32, a: u32) -> Option<f64>Expand description
Natural isotopic abundance (mole fraction) for a given isotope.
Returns None for isotopes with no natural occurrence (synthetic elements
such as Tc, Pm, or transuranic elements like Pu) or isotopes not in the
IUPAC 2016 database. Callers requiring reactor/engineered material compositions
(e.g. Pu-239 in fuel) must supply the abundance explicitly.
ยงExamples
assert!((endf_mat::natural_abundance(92, 238).unwrap() - 0.992742).abs() < 1e-6);
assert_eq!(endf_mat::natural_abundance(43, 99), None); // Tc is synthetic
assert_eq!(endf_mat::natural_abundance(94, 239), None); // Pu has no natural abundance