Characterization of the Uniformity of High-Flux CdZnTe Material

Abstract

Since the late 2000s, the availability of high-quality cadmium zinc telluride (CdZnTe) has greatly increased. The excellent spectroscopic performance of this material has enabled the development of detectors with volumes exceeding 1 cm3 for use in the detection of nuclear materials. CdZnTe is also of great interest to the photon science community for applications in X-ray imaging cameras at synchrotron light sources and free electron lasers. Historically, spatial variations in the crystal properties and temporal instabilities under high-intensity irradiation has limited the use of CdZnTe detectors in these applications. Recently, Redlen Technologies have developed high-flux-capable CdZnTe material (HF-CdZnTe), which promises improved spatial and temporal stability. In this paper, the results of the characterization of 10 HF-CdZnTe detectors with dimensions of 20.35 mm × 20.45 mm × 2.00 mm are presented. Each sensor has 80 × 80 pixels on a 250-μm pitch and were flip-chip-bonded to the STFC HEXITEC ASIC. These devices show excellent spectroscopic performance at room temperature, with an average Full Width at Half Maximum (FWHM) of 0.83 keV measured at 59.54 keV. The effect of tellurium inclusions in these devices was found to be negligible; however, some detectors did show significant concentrations of scratches and dislocation walls. An investigation of the detector stability over 12 h of continuous operation showed negligible changes in performance.

Charge Sharing and Charge Loss in High-Flux Capable Pixelated CdZnTe Detectors

“…The agreement between the experimentally determined charge sharing rates and simulation set to the applied external bias of −750 V ( Figure 9 ), suggests that the electric field strength within the HF-CdZnTe does not significantly suffer from local distortions and is uniform. Little spatial variation in the charge sharing proportions across the HF-CdZnTe detector support this finding [ 28 ]. This is a likely explanation for the better isolated event photopeak performance of the HF-CdZnTe compared with the spectroscopic grade CdZnTe.…”

“…Veale at al. [ 28 ] investigated the variation in performance across a sample of 10 of these detectors all designed to the same specifications. One of the detectors included in their study (serial number D185739) is the one used in this work.…”

Recent advances in the development of high-resolution 3D cadmium–zinc–telluride drift strip detectors

“…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). Aside from its appealing physical properties (high atomic number, wide band gap, high density), this success can mainly be attributed to the important advancements in both crystal growth and device fabrication technologies (Abbene et al, 2016(Abbene et al, , 2020Chen et al, 2008;Iniewski, 2014;Prokesch et al, 2018;Szeles et al, 2008;Thomas et al, 2017;Veale et al, 2020;Zappettini et al, 2009).…”

Fabrication of Small-Pixel CdZnTe Sensors and Characterization with X-rays

“…In the context of this article, small-pixel CdZnTe sensors hybridized with Timepix ASIC have been tested to respond to the new sensor requirements for the Extremely Brilliant Source (EBS) upgrade of the European Synchrotron Radiation Facility (ESRF). Prior tests of X-ray imaging with fine-pixel pitch CdZnTe detectors have been carried out with Timepix ASIC [ 15 ] (55 and 110 pitch) and with HEXITEC ASIC [ 16 , 17 ], (250 pitch). Some of these recent contributions make use of a special CdZnTe grown by Redlen Technologies and optimized for applications with high photon fluxes.…”