8.15 Diamond Detectors for Dosimetry

Diamond dosimetry is an appealing system for measurements in radiotherapy. In this chapter the physical, chemical and electronic properties of diamond are analyzed and reported. The theory of induced photoconductivity in diamond is discussed. The commercial natural diamond dosimeter is described and its behavior analyzed from the point of view of the cavity theory. A detailed report of main related results in the literature is given. All the parameters of interest for dosimetry are considered (reproducibility, signal linearity, energy dependence, dose rate dependence, priming effects, rise and decay times, etc.). Synthetic diamonds are now receiving the greatest attention. Growth modalities, electrical contacts and packaging, and their influence on detector behavior are shortly discussed. Main dosimetric results are reported in detail, accounting for all the parameters of interest. The behavior of polycrystalline (pCVD) and single crystal (sCVD) devices are compared. Finally the applications of synthetic diamond as “off-line” dosimeter are shortly analyzed.