Estimation of the response of ion chamber detectors to beta radiation

A technique was developed to calculate the response of cylindrical ion chambers to large area beta sources. Beta particles were simulated as vectors originating from a point on a source plane. Response calculations were performed for various source-plane-to-detector distances. The data testified to the dependency of response on source position and size. The results were compared with measured data. The technique was then used to evaluate the response characteristics of two chamber designs. Results showed that a design with concentric dual chambers could provide a means to estimate source geometry and distance. In addition, a detector employing stacked thin chambers could directly measure the extent of non-uniform ionisation in the chamber. (author)