Properties of GaAs:Cr-based Timepix detectors

TL;DR

This paper investigates GaAs:Cr-based Timepix detectors, focusing on their electrical, stability, and imaging properties, to evaluate their potential for high-energy X-ray spectroscopic imaging applications.

Contribution

It provides comprehensive characterization of GaAs:Cr sensors integrated with Timepix detectors, highlighting their suitability for high-energy X-ray imaging beyond silicon capabilities.

Findings

GaAs:Cr sensors show stable IV characteristics

Detectors demonstrate good spatial and energy resolution

Temperature affects charge transport properties

Abstract

It is the hybrid pixel detector technology which brought to the X-ray imaging a low noise level at a high spatial resolution, thanks to the single photon counting. However, silicon as the most widespread detector material is marginally sensitive to photons with energy more than 30 keV. That's why the high-Z alternatives to silicon such as gallium arsenide and cadmium telluride are increasingly attracting attention of the community for the development of X-ray imaging systems in recent years. We present in this work the results of our investigations of the Timepix detectors bump-bonded with sensors made of gallium arsenide compensated by chromium (GaAs:Cr). The properties which are mostly important from the practical point of view: IV characteristics, charge transport characteristics, operational stability, homogeneity, temperature dependence as well as energy and spatial resolution are considered. Applicability of these detectors for spectroscopic X-ray imaging is discussed.