Speaker
Description
X-ray detection plays a crucial role in medical imaging, industrial inspection, and security. At present, X-ray detectors are typically categorized into two types: direct conversion and indirect conversion methods. Semiconductor-based direct radiation detection, utilizing materials such as CdZnTe, CdTe, GaAs and metal halide perovskites, has rapidly advanced and demonstrated diverse applications, including X-ray imaging. Direct detectors offer a wide linear response range, rapid pulse rise times, and high energy and spatial resolution.
In this work, a hybrid semiconductor pixelated detector (Timepix) has been used to investigate the imaging quality assessment under low-dose X-ray environment. Timepix3 is a single-photon counting type based readout ASIC chip. The hybrid pixel device, developed at CERN, features a 256 × 256 array of square pixels with a 55 µm pitch and comprises a semiconductor sensor layer (2 mm CdTe in this study) bump-bonded to a readout ASIC. An indirect X-ray detector comprising a CMOS flat-panel sensor coupled with a scintillation film was employed for image quality comparison. The CMOS flat-panel detector features a 512 × 1,024 photodiode array with a pixel pitch of 48 µm and an active area of 24.6 × 49.2 mm². Furthermore, the block-matching and 3D filtering (BM3D) denoising algorithm was applied to the Timepix3 images due to its ability to effectively reduce noise while maintaining edge sharpness and fine structural features. Imaging performance was assessed in terms of spatial resolution, X-ray sensitivity, signal-to-noise ratio (SNR) and X-ray transmission imaging experiments with object phantoms were performed under low-dose conditions.