Detector module development for the High Efficiency Multimode Imager

The High Efficiency Multimode Imager (HEMI) is an instrument currently under development for the purpose of detecting, locating, and spectroscopically characterizing gamma-ray emission sources at long-range standoff distances. The instrument design consists of multiple planes of relatively large-volume, good-energy-resolution detector modules configured for combined coded aperture and Compton scatter (multimode) gamma-ray imaging. The basic building block of HEMI is a detector module consisting of a CdZnTe coplanar-grid detector packaged along with its front-end and pulse-shaping electronics. We have developed a module that can be used to form close-packed arrays, has low dead mass, and is easily adjusted for optimum spectroscopic performance. In this paper, we provide an overview of HEMI and then detail the design, production, and testing of the detector modules.