Review of INFN activities on characterization and applications of hybrid pixel detectors based on Timepix4 ASIC

The Medipix4 international collaboration represents a landmark initiative in the field of pixelated radiation imaging and detection. Building on the successes of its predecessors—the Medipix2 and Medipix3 collaborations—this effort has been pivotal in advancing hybrid pixel detector technology for a wide range of applications, including medical imaging, particle physics, and material science. The collaboration brings together a consortium of research institutions and industry partners, leveraging decades of expertise to push the boundaries of detector performance and integration. The aim of the Medipix4 collaboration is the development of two state-of-the-art application-specific integrated circuits (ASICs): Timepix4 and Medipix4. These ASICs are designed to address critical challenges in pixelated detection systems, including enhanced spatial resolution, higher data throughput, and improved energy resolution, while maintaining compatibility with a wide range of detector materials. The Italian Institute for Nuclear Physics (INFN) has been a member of the Medipix4 collaboration since 2020. This review reports the various activities that have been carried out by INFN to fully characterize the performance of detectors based on this technology. Various assemblies composed of a Timepix4 ASIC bump-bonded to Si-sensors with different thicknesses and material characteristics were manufactured and tested.