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The outstanding material properties make silicon carbide radiation hard and this ability has enabled it to be demonstrated in a range of detector structures for deployment in extreme environments, including those where the ability to tolerate high radiation dose is imperative. This includes applications in space and nuclear environments, where the ability to detect highly energetic radiation is important. In contrast, detectors used in medical treatment, such as imaging and radiotherapy, uses a range of radiation dose rates and energies for both particulate and photonic radiation. Here, we report the response and dose rate linearity of detectors fabricated from silicon carbide to dose rates in the range of 0.185 mGy.min −1 , typical of those used for medical imaging. The data show that the radiation detected current originates within the depletion region of the detector and that the response is linearly dependent on the volume of the space charge region. The realization of a vertical detector structure, coupled with the high quality of epitaxial layers, has resulted in a high dose sensitivity of the detector that is highly linear. The temperature dependence of the characteristics indicate that silicon carbide Schottky diode based detectors offer a performance suitable for medical applications at temperatures below 100 • C without the need for external cooling.

Plastic scintillators are commonly used for medical dosimetry due to the density and effective atomic numbers that are closer to human soft tissue. When a photomultiplier tube (PMT) is used with a thin scintillator, reflected photon and electrons as a result of Compton scattering either inside the scintillator or PMT entrance window, might contribute to a significant source of additional absorbed dose. Monte Carlo simulation was used to study the effect of different PMT window materials on the absorbed dose of a 0.5 mm plastic scintillator cast sheet for parallel photon beam energy up to 1 MeV. The additional dose in the plastic scintillator from 400 keV to 1 MeV due to sapphire and lithium fluoride (LiF) glass are increases from 11 % to 47 % and 8 % to 31 %, respectively. Despite of the lower density of Quartz among other materials, Quartz and magnesium fluoride (MgF2) demonstrate almost similar trends of additional dose throughout the energies, which is closer to the sapphire. To reduce the unexpected additional dose, a plastic scintillator with a considerable thickness of a PMT window should be adopted for the ‘soft-tissue’ dose response.

There is increasing interest in the development of radiation hard detector materials with the capability to discriminate within wide dose range and high radiation tolerance that are sensitive, and show a linear response. In this study, fabricated 4H-SiC Schottky diodes were exposed to dose rates ranging from 0.02 to 0.185 mGy/min to analyse the linearity and sensitivity at room temperature. High linearity response presented from the graph of current signal plotted versus dose rate which show enhancement of 104 in comparison to previous studies. The sensitivity measured at different bias voltages by exposing to 0.185 mGy/min dose rate show good reproducibility and stability of the current signal with time. Collected charge presented for all diodes exhibit linear behaviour of photon induced collected charge with the sensitivity between 1.40 to 8.38 x 105 nC/Gy for the 0.20 to 1 mGy absorbed dose range. Thus, these devices are ideally suited for the realisation of radiation detectors at moderate dose range.