“…The desire for room-temperature gamma-ray spectroscopic imagers with sub-millimetre spatial resolution in 3D and energy resolutions close to the superb resolutions of cooled high-purity germanium (HPGe) detectors (0.3% FWHM at 662 keV) (Abbene et al, 2013a,b;Knoll, 2000) has stimulated intense research activities on the development of 3D cadmium-zinc-telluride (CdZnTe or CZT) detectors. Roomtemperature measurements of photon energy, timing and 3D positioning up to the megaelectronvolt region are key requirements for several applications in astrophysics (Kuvvetli et al, 2010), medical imaging (Abbaszadeh et al, 2016;Drezet et al, 2007;Peng & Levin, 2010) and nuclear security (Johns & Nino, 2019;Wahl & He, 2011. Since the first spectroscopic grade detector was fabricated (Butler et al, 1992), CZT now represents the leading detector material over high-Z and wide-band-gap compound semiconductors (Del Sordo, 2004Sordo, , 2009 Takahashi & Watanabe, 2001;Turturici et al, 2014).…”