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The X-ray imaging has spread from medicine to other fields of our lives like industry or art. Its digitalization has brought advantages in prompt processing, enabled postprocessing and in enhanced image contrast. In the last decade, an intensive development of the next generation of digital imaging devices occurs. These devices are based on a matrix of individual semiconductor pixel detectors fused with their readout electronics on an area of μm size, called hybrid pixel detectors. They operate in single photon detection regime with an adjustable threshold for each pixel, resulting in practically to no noise images with wide dynamic ranges. Among this generation of X-ray imaging devices belong also the pixelated detectors based on the Timepix chip family, developed in collaboration of leading European research institutions and the CERN. Our research team based on a collaboration between the Institute of Nuclear and Physical Engineering (STU) and the Institute of Electrical Engineering (SAS) is developing two new types of radiation hard sensors for pixelated Timepix detectors. The typical Timepix sensor based on a silicon semiconductor, which is meeting its inherent limits in radiation hardness and absorption of X-rays, is being replaced by sensors based on SiC and GaAs. The degradation of these materials from point of view of spectrometry is 100-times lower in comparison to silicon at similar absorbed doses. Regarding the absorption of X-rays, GaAs based sensor has 20-times higher detection efficiency than the silicon sensor, which leads to substantially shorter required period of exposition. This fact represents important contribution in the area of medicine, when irradiation dose of patients will be significantly decreased. Another advantage of SiC and GaAs sensors is their high radiation hardness and the ability of SiC sensor to operate at elevated temperatures (up to several hundred of degrees Celsius) without serious operational degradation. Beside digital radiography the Timepix detectors are able to recognise tracks of various particles which finds application in mixed radiation fields monitoring including space.
Acknowledgement: Presented work was supported by grants of the Slovak Research and Development Agency No. APVV-22-0382, APVV-18-0273, DS-FR-22-0012 and it has received funding from the European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730.
