Calculation of neutron-induced physical doses in human tissues

Improved multicollision neutron fluence-to-dose conversion factors have been calculated for a phantom exposed to neutrons with energies from 15 MeV down to thermal. The phantom was a 30-cm-thick slab composed of the 11 most common elements in the standard man. The calculations consisted of the simultaneous solution of the neutron and secondary gamma-ray transport problem with the ANISN computer code for both a beam source and an isotropic flux source, and for a slab having both infinite and finite transverse dimensions. The fluence-to-dose conversion factors were based on new neutron fluence-to-kerma factors and improved secondary gamma-ray yields determined for the individual elements comprising the slab. The neutron and gamma-ray cross sections used in the calculations are from the ENDF/B file and the OGRE library, respectively.