Dosimetric characterization of CVD diamonds in photon, electron and proton beams

Synthetic diamond is potentially one of the more interesting materials in the field of detectors applicable in dosimetry. It is, in fact, tissue equivalent (its atomic number, Z = 6, is very close to the actual atomic number of a biological tissue, Z = 7.5. Moreover it is not toxic and shows a high resistance to radiation damage, a high sensitivity and stability of response, a low leakage current and a good time resolution. It is an electrical insulator, chemically stable, robust and realizable in small size. Considering these features, there is a very high motivation to characterize synthetic diamond as an on line dosemeter. The diamond can be used in on line dosimetry studying the change of conductivity induced during the exposure to an ionizing radiation. The current-voltage characteristic, the preirradiation effect, the linearity of response with dose, dose rate effects, and the LET dependence have been studied for a commercial CVD diamond by De Beers [1], [2] in order to verify its applicability for dosimetry in the radiotherapy field.