Perturbation correction for ionometric determination of absorbed dose in a graphite phantom for60Co gamma rays

Abstract

Calculations have been made of the perturbation correction to be applied to a flat cavity ionisation chamber. This makes possible the use of such a chamber as a primary standard of absorbed dose in graphite for ⁶⁰Co gamma rays. The good agreement between ionometric measurements and the calorimetric measurements of national laboratories of metrology gives strong support to the reliability of the calculated correction.