title: Comparison of natural and synthetic diamond X-ray detectors.
abstract: Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolution resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high-quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kV), and dose-rate dependence of charge at linear accelerator energy (6 MV). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response with dose (at 100 kV) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 V compared to a bias of 61.75 V used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the synthetic diamond detector. Overall, the synthetic diamond detector performed well in comparison to the natural diamond detector.
authors.affiliation: Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand. stuart.lansley@canterbury.ac.nz
authors.forename: S P
authors.initials: SP
authors.lastname: Lansley
authors.forename: G T
authors.initials: GT
authors.lastname: Betzel
authors.forename: P
authors.initials: P
authors.lastname: Metcalfe
authors.forename: L
authors.initials: L
authors.lastname: Reinisch
authors.forename: J
authors.initials: J
authors.lastname: Meyer
mesh_terms: D018130:Diamond / Q000737:chemistry*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D019047:Phantoms, Imaging; D011874:Radiometry / Q000295:instrumentation*; D014964:X-Ray Therapy / Q000295:instrumentation*; D014965:X-Rays
chemical_list: D018130:Diamond