The performance characteristics of a diamond probe in an electron beam

A dedicated probe with a synthetic diamond as the sensor element has been designed to provide the input signal to a commercial PTW electrometer system. The response characteristics of the diamond probe configuration under irradiation by an electron beam from the a radiotherapy linear accelerator are compared to the responses from the more conventional Markus chamber, Cylindrical probe and diode probe configurations under identical irradiation conditions. Depth dose responses and field parameters are compared as well as absolute dose measurements which are compared to the values obtained from the Markus chamber the internationally accepted standard chamber for absolute dose values. The angular response characteristics of the diamond probe are compared to the results obtained from the cylindrical chamber. EGS - 4 calculations have also been made after adaptation of the code to a PC running under DOS and Microsoft FORTRAN - Windows version. The tissue equivalence and small volume size of the diamond probe make the proposed configuration attractive for the electron beam measurements. The results indicate that a high degree of confidence can be placed in the diamond probe - PTW electrometer configuration overall. 2 refs. ( author )