Towards high-resolution X-ray spectral imaging

This work presents the development and preliminary testing of a novel class of Hybrid Pixel Detectors (HPDs), built by coupling a low-noise, event-driven analog readout ASIC with a fine-pitch solid-state pixel sensor. Our new HPD builds upon XPOL-III, a readily-available cutting-edge 180 nm CMOS VLSI ASIC integrating over 100,000 pixels with fully analog readout at 50$\mu \text{m}$ pitch on a hexagonal grid, with an active area of $15\times 15{\text{mm}}^2$. We developed two versions of the hybrid device: one with 750$\mu \text{m}$ thick and 100$\mu \text{m}$ pixel pitch, Schottky-type CdTe sensor, and one with 300$\mu \text{m}$ thick and 50$\mu \text{m}$ pixel pitch silicon sensor. The assembled devices exhibit excellent performance with full single-photon sensitivity, demonstrating strong potential for advanced X-ray spectral imaging applications. Spatial and energy resolution measurement results for both the silicon and CdTe devices will be presented. These results open up exciting perspectives for the implementation of high-performance HPDs in various fields requiring precise X-ray imaging and spectroscopy. We will discuss the detailed performance metrics of the two devices and explore the implications of this technology for future developments in X-ray detection systems.