<p>Low Electronic Noise Hybrid-Binning Subpixel X-ray Detector for MeV Imaging Applications</p>

In MeV X-ray imaging applications, severe local attenuation often occurs within inspected objects. Under such low-signal conditions, the influence of noise sources on image quality becomes increasingly pronounced. Common MeV X-ray detectors typically employ large-pixel, wide-dynamic-range, energy-integrating scintillator detectors, in which electronic noise mainly originates from sensor capacitance, feedback capacitance, and dark current. In high-attenuation regions, the relative contribution of electronic noise increases, while inter-pixel response non-uniformity has a stronger effect on image contrast and stability. To address this, we propose a novel detector based on a subpixel architecture combined with a hybrid-binning strategy. In this design, each sensor pixel is subdivided into an n × n array of smaller subpixels that are read out individually and subsequently merged using a hybrid-binning strategy at the circuit level. Importantly, the front-end scintillator remains a single, undivided crystal, ensuring that detection efficiency is preserved. This structure reduces electronic noise and suppresses pixel-level response variations in the final image, leading to improved imaging uniformity and contrast-to-noise ratio (CNR). Experimental tests compared a normal detector (size: 5 × 5 mm²) with a 2 × 2 hybrid-binning subpixel detector (subpixel size: 2.5 × 2.5 mm²). The proposed detector achieves an approximately 35% reduction in electronic noise and about a 30% improvement in CNR in penetration imaging experiments. These results demonstrate the synergistic advantages of the subpixel architecture and hybrid-binning strategy for MeV imaging under high-attenuation conditions, providing a new approach for detector optimization in complex imaging scenarios.