Measurement of Depth Doses in Rat and Mouse Phantoms Exposed to ²⁵²Cf Mixed Neutron and Gamma Radiations

Abstract

Depth doses in rat and mouse phantoms from the ²⁵²Cf neutron beam were determined using a pair of gas flow type tissue equivalent, and magnesium ionization chambers, which were especially designed for measuring depth doses in phantoms. Depth dose distribution and neutron-to-gamma dose ratios in the central plane of a rat phantom are included. The dose distribution with a unilateral irradiation was found to be nonuniform, however, if significantly be improved by adopting bilateral or rotation irradiation. Kerma rates were determined using four types of tissue equivalent ionization chambers and two kinds of non-hydrogenous ionization chambers (aluminum and magnesium), employed in pairs. The best kerma rate value was estimated. Tissue-air ratios for both phantoms were calculated based on the results of kerma rate and absorbed dose data obtained at the centers of the rat and mouse phantoms.