Calculation of Neutron Fluence-to-Kerma Factors for the Human Body

Abstract

Fluence-to-kerma factors (where fluence is the time-integrated neutron flux and kerma is equal to the total kinetic energy released in materials resulting from direct neutron interaction per unit mass of the irradiated medium) were calculated at discrete neutron energies from 0.025 eV to 15 MeV for various compositions of the human body—tissue, muscle, bone, lung, brain, red marrow, and the “standard man” composition. The 11 most common elements in man were considered and the latest cross sections used. An attempt was made to include all significant reactions, namely elastic scattering with an anisotropic correction, inelastic scattering, neutron capture, (n, 2n) reactions, (n, charged particle) reactions, and beta or positron emissions from these reactions. These calculations show improvements in the entire energy range over previously reported neutron kerma factors.