Determination of absorbed dose in fields of fast neutrons

Sammanfattning: Analytical models have been developed to solve energy deposition problems in finite detectors and near interfaces in beams of fast neutrons. Dose expressions have been derived, which are suitable for numerical evaluation. The detectors or volumes of interest have been characterized by distributions of chord length along which the particles travel. The approximations obtained by using a single mean chord length instead of a chord length distribution have also been investigated. The theoretical models have been carefully tested in beams from modern neutron therapy units, monoenergetic neutron sources and fission neutron sources. The models have further been applied to calculate the dose in bone marrow cavities and dose distributions near interfaces in the human body.