The dosimetric aspects of the Health Physics Research Reactor (HPRR) have been carefully investigated and are reported herein. Studies of parameters such as quantity and symmetry of neutron leakage from the reactor core were included in the work which was done primarily to obtain neutron and gamma-ray air-dose curves as a function of distance. These curves are used both for selecting reactor power levels and exposure times to obtain predesignated radiation exposures and, together with a dependable and reproducible normalization channel, to provide quantitative dose information with an estimated accuracy of ±10%. The fast neutron leakage from the HPRR is 1.3 neutrons per fission. The first collision neutron dose rate at a distance of 2 m with reactor and detector heights of 2 m, is 3.3 ± 0.13 mrad/unit activation of the normalization sulfur pellet. For this reasonably good experimental geometry (H/D = 1), the scattered-to-total neutron dose ratio is 21%, and the neutron-to-gamma-ray dose ratio is approximately 7:1.
