U.S. Department of Commerce


Date of this Version



Published in Nucl. Tracks Radiat. Meas., Vol. 16. No. 2/3. pp. 187-195. (1989)


The process by which neutrons transfer their energy to tissue is described, including the deposition of energy by secondary charged particle tracks in small sites; that is, microdosimetry and nanodosimetry. Three approximations are considered in order of increasing amounts of information on track structure: the continuous slowing-down approximation (CSDA), the straggling approximation, and the delta-ray approximation. Although simple approximations sometimes work quite well, much work remains to be done for very small sites, and for the inclusion of the effects of "passers" in the calculations.