research papers 1564 https://doi.org/10.1107/S1600577520010747 J. Synchrotron Rad. (2020). 27, 1564–1576 Received 22 May 2020 Accepted 4 August 2020 Edited by P. A. Pianetta, SLAC National Accelerator Laboratory, USA Keywords: X-ray and gamma-ray detectors; 3D CdZnTe detectors; drift strip detectors; spectroscopic X-ray and gamma-ray imaging. Recent advances in the development of high-resolution 3D cadmium–zinc–telluride drift strip detectors Leonardo Abbene, a * Gaetano Gerardi, a Fabio Principato, a Antonino Buttacavoli, a Saverio Altieri, b,c Nicoletta Protti, b,c Elio Tomarchio, d Stefano Del Sordo, e Natalia Auricchio, f Manuele Bettelli, g Nicola Sarzi Amade `, g Silvia Zanettini, h Andrea Zappettini g and Ezio Caroli f a Department of Physics and Chemistry (DiFC), University of Palermo, Viale delle Scienze, Edificio 18, Palermo 90128, Italy, b Nuclear Physics National Institute (INFN), Unit of Pavia, via Agostino Bassi 6, Pavia 27100, Italy, c Department of Physics, University of Pavia, via Agostino Bassi 6, Pavia 27100, Italy, d Department of Engineering, University of Palermo, Viale delle Scienze, Edificio 6, Palermo 90128, Italy, e INAF/IASF Palermo, Palermo Italy, f INAF/OAS Bologna, Bologna, Italy, g IMEM/CNR, Parco Area delle Scienze 37/A, Parma 43100, Italy, and h due2lab s.r.l., Via Paolo Borsellino 2, Scandiano, Reggio Emilia 42019, Italy. *Correspondence e-mail: leonardo.abbene@unipa.it In the last two decades, great efforts have been made in the development of 3D cadmium–zinc–telluride (CZT) detectors operating at room temperature for gamma-ray spectroscopic imaging. This work presents the spectroscopic performance of new high-resolution CZT drift strip detectors, recently developed at IMEM-CNR of Parma (Italy) in collaboration with due2lab (Italy). The detectors (19.4 mm  19.4 mm  6 mm) are organized into collecting anode strips (pitch of 1.6 mm) and drift strips (pitch of 0.4 mm) which are negatively biased to optimize electron charge collection. The cathode is divided into strips orthogonal to the anode strips with a pitch of 2 mm. Dedicated pulse processing analysis was performed on a wide range of collected and induced charge pulse shapes using custom 32-channel digital readout electronics. Excellent room-temperature energy resolution (1.3% FWHM at 662 keV) was achieved using the detectors without any spectral corrections. Further improvements (0.8% FWHM at 662 keV) were also obtained through a novel correction technique based on the analysis of collected-induced charge pulses from anode and drift strips. These activities are in the framework of two Italian research projects on the development of spectroscopic gamma-ray imagers (10–1000 keV) for astrophysical and medical applications. 1. Introduction 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. Room- temperature 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, 2015). Since the first spectro- scopic 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, 2004, 2009; Johns & Nino, 2019; Owens & Peacock, 2004; Principato ISSN 1600-5775 # 2020 International Union of Crystallography