Silicon carbide (chemical name silicon carbide, SiC) is a promising semiconductor material suitable for use as an ionizing radiation detector. It is highly radiation resistant and also chemically and thermally stable. Due to their advantageous properties, SiC-based sensors are mainly applicable in environments with high temperature and also ionizing radiation intensity.
We prepared pixel sensors using a high quality epitaxially grown SiC layer. The semiconductor sensor has an active size of 14.1 × 14.1 mm2 (256 × 256 pixels) with a single pixel size of 55 × 55 mm2. The SiC sensor is directly pixel-by-pixel (or sandwiched) interconnected with a Timepix3 readout chip developed at CERN, which provides the collection of the electrical signals from the individual pixels of the sensor and also their digital processing. When ionising radiation interacts with the sensor material, an electrical signal is generated and transmitted to the collection electrode of the nearest pixel. The readout chip is capable of acquiring multiple pieces of information which are transmitted to its output. We can identify in which pixel(s) the signal or interaction of the incident radiation occurs, the magnitude of the electrical signal is directly proportional to the energy absorbed in the pixel sensor, and we also know the time at which the interaction of the radiation with the sensor occurred. Based on the tracsk that the radiation leaves in the pixel detector, we can identify its type, e.g. electrons, protons, gamma rays, etc. By further processing the signal, we can determine the energy spectrum of the incident radiation and thus identify its source. And of course, we can also use ionising radiation (especially X-rays) to image the internal structure of the test objects through which the radiation passes.
Schematic representation of SiC sensor interconnected with readout electronics
Tracks of ionizing radiation created in a pixel sensor.
Energy spectrum of ionizing radiation detected by a SiC radiation camera.
X-ray image of the printed circuit board used to test the imaging quality of the SiC radiation camera.
Authors: B. Zaťko, L. Hrubčín, E. Kováčová
Link: Zaťko, B., Šagátová, A., Hrubčín, L., Kováčová, E., Novák, A., Kurucová, N., Polansky, Š., and Jakůbek, J.: Imaging and spectrometric performance of SiC Timepix3 radiation camera, J. Instrument. 19 (2024) C01003.