A study of radiation dosimeters based on synthetic HPHT diamond

• Published in: Diamond and related materials 2007-02, Vol.16 (2), p.191-195
• Main Authors: Marczewska, B., Kupriyanov, I., Pal'yanov, Yu, Nowak, T., Olko, P., Rębisz, M., Waligórski, M.P.R.
• Format: Article
• Language: English
• Subjects: Defects; Detectors; Diamond crystal; High pressure high temperature (HPHT)
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2006.04.009

We investigated the applicability of synthetic diamond crystals routinely produced by the HPHT (High Pressure High Temperature) technique for the detection of ionising radiation. Split-sphere-type multi-anvil equipment was used to produce these HPHT diamonds. Both as-grown type Ib and HPHT treated type IaA diamonds were examined at the Centre of Oncology in Kraków using a therapeutic Co-60 γ-ray beam. Detectors fabricated from type IaA diamonds showed, on average, better performance than those based on type Ib diamonds. IaA- type synthetic diamonds containing up to 150-200 ppm nitrogen showed sensitivity up to 160 nC/(Gy mm 3), charge collection distance up to 180 μm and close to linear dose-rate response. Considerable variations in the detecting characteristics were observed for the devices containing similar concentrations of nitrogen. From our preliminary qualitative analysis we conclude that the observed response variations may be associated with varying concentration of the nickel impurity present in these diamond crystals.