Recent progress in californium-252 dosimetry

Studies are being conducted on increasing the accuracy of dose determinations in irradiated animals with small implanted tumors. Three experimental methods of in-phantom dosimetry are being employed in this work since any one method thus far has not led to a determination of dose to an accuracy within 5 percent at distances close to a source and since each method has distinct advantages for a given problem. Descriptions are given of these methods which are as follows: dosimetry using dielectric ionization chambers; dose contribution from moderated neutrons near a Cf source; and measurement of dose at various locations in a tumor-mouse radiobiological system