Chromatic X-Ray imaging with a fine pitch CdTe sensor coupled to a large area photon counting pixel ASIC

TL;DR

This paper introduces a high-resolution, energy-separating X-ray imaging sensor using a CdTe detector and photon counting ASIC, enabling real-time dual-energy imaging at high speeds with improved image quality and dose efficiency.

Contribution

It presents a novel chromatic photon counting X-ray sensor with real-time energy discrimination and high spatial resolution, integrating a CdTe sensor with a large-area ASIC.

Findings

High spatial resolution (>10 l.p./mm at MTF50) achieved

Real-time dual-energy imaging demonstrated

Multiple tile configurations tested successfully

Abstract

An innovative X-ray imaging sensor with intrinsic digital characteristics is presented. It is based on Chromatic Photon Counting technology. The detector is able to count individually the incident X-ray photons and to separate them according to their energy (two 'color' images per exposure). The energy selection occurs in real time and at radiographic imaging speed (GHz global counting rate). Photon counting, color mode and a very high spatial resolution (more than 10 l.p./mm at MTF50) allow to obtain an optimal ratio between image quality and absorbed dose. The individual block of the imaging system is a two-side buttable semiconductor radiation detector made of a thin pixellated CdTe crystal (the sensor) coupled to a large area VLSI CMOS pixel ASIC. 1, 2, 4, 8 tile units have been built. The 8 tiles unit has 25cm x 2.5cm sensitive area. Results and images obtained from in depth testing of several configurations of the system are presented. The X-Ray imaging system is the technological platform of PIXIRAD Imaging Counters s.r.l., a recently constituted INFN spin-off company.