Characterization of a new commercial single crystal diamond detector for photon- and proton-beam dosimetry

Abstract

A synthetic single crystal diamond detector (SCDD) is commercially available and is characterized for radiation dosimetry in various radiation beams in this study. The characteristics of the commercial SCDD model 60019 (PTW) with 6- and 15-MV photon beams, and 208-MeV proton beams, were investigated and compared with the pre-characterized detectors: Semiflex (model 31010) and PinPoint (model 31006) ionization chambers (PTW), the EDGE diode detector (Sun Nuclear Corp) and the SFD Stereotactic Dosimetry Diode Detector (IBA). To evaluate the effects of the pre-irradiation, the diamond detector, which had not been irradiated on the day, was set up in the water tank, and the response to 100 MU was measured every 20 s. The depth–dose and profiles data were collected for various field sizes and depths. For all radiation types and field sizes, the depth–dose data of the diamond chamber showed identical curves to those of the ionization chambers. The profile of the diamond detector was very similar to those of the EDGE and SFD detectors, although the Semiflex and PinPoint chambers showed volume-averaging effects in the penumbrae region. The temperature dependency was within 0.7% in the range of 4–41°C. A dose of 900 cGy and 1200 cGy was needed to stabilize the chamber to the level within 0.5% and 0.2%, respectively. The PTW type 60019 SCDD detector showed suitable characteristics for radiation dosimetry, for relative dose, depth–dose and profile measurements for a wide range of field sizes. However, at least 1000 cGy of pre-irradiation will be needed for accurate measurements.

Suitability of microDiamond detectors for the determination of absorbed dose to water around high‐dose‐rate 192Ir brachytherapy sources

“…These findings show a major advantage of microDiamonds over natural diamond detectors and are in line with other studies where negligible dose‐rate dependence and deviations in signal stability within ±0.5% were observed for preirradiation doses below 3 Gy . Nevertheless, several authors observed individual behavior among microDiamond detectors and unusually high preirradiation doses of up to 12 Gy …”

“…To assess this hypothesis, three microDiamond detectors were used to determine absorbed dose to water using two clinical HDR 192 Ir BT treatment delivery systems. The results presented in this paper will contribute to the development of HDR BT dosimetry and also complement the current characterization of microDiamond detectors …”

“…A detailed description of its structure and detection properties can be found elsewhere . Characterization in high‐energy photon beams showed that it has linear response to dose from 0.5 to 15 Gy, good stability, negligible dose‐rate dependence, uniform energy response (including low‐energy scattered photons) and low angular and temperature dependences . Since dosimetry of HDR 192 Ir BT sources is similar to that of small photon fields in terms of high dose gradients and high dose rates, these findings, coupled with near water‐equivalence of carbon, direct readout and convenience of use, suggest that the microDiamond would be suitable for the determination of absorbed dose to water in HDR 192 Ir beams.…”

Response of synthetic diamond detectors in proton, carbon, and oxygen ion beams

“…LET‐value increases upto ~20 keV/μm, at the depth corresponding to the range 80%. As expected, results confirm the LET‐independent response observed in previous experimental work . Considering the uncertainties of the results, a LET dependence of the microDiamond detectors is not measurable and we conclude that there is agreement between the normalized response of the microDiamond detectors and the normalized response of Markus ionization chamber.…”

“…In photon, electron and proton beams, this detector is described as suitable for small field dosimetry . Also in protons, most dosimetry studies conclude that the response of the PTW‐60019 microDiamond detector exhibits no LET dependence nor quenching effect (Mandapaka et al, Marinelli et al, Yuichi et al, Rossomme et al, Akino et al). In, which is based on an intercomparison of four microDiamond detectors in a clinical 138 MeV proton beam, authors reported a nonreproducibility between devices in terms of stability, sensitivity, and LET dependence.…”