Recent improvements on the use of CVD diamond ionisation chambers for radiotherapy applications

Diamond interests for radiotherapy applications have often been tempered due to the inherent presence of defects in the material that alter the dosimetric properties. In the present paper, we illustrate this problem by focusing on the influence of defect levels on the stability and reproducibility of the device responses under X-rays. Results presented here show clear influence of shallow and deep levels and a way to control and remove their effects by the control of the sample temperature. Since defect influence can be controlled from the use of variable temperatures of diamond ionisation chambers, we propose specific device geometry where the diamond sensing part is coupled with a diamond heater, thus not altering the tissue equivalence of the ionisation chamber.