1/v law absorption cross-section sigma(v) = sigma_0 v_0/v; Riemann-integrable

1/v-law neutron-absorption framework (Bohr 1936 Nature 137, 344; Bethe 1937 Rev Mod Phys 9, 69). Setup: for thermal neutrons (E < 1 eV), the absorption cross-section sigma_a(v) is inversely proportional to v: sigma_a(v) = sigma_0 v_0/v…