Spectral analysis for the High Efficiency Multimode Imager

The High Efficiency Multimode Imager, HEMI, is a combined Compton and coded aperture imager designed to detect, localize, and characterize gamma-ray sources within the energy range from tens of keV to a few MeV. HEMI consists of cubic centimeter CdZnTe detectors with good spectral resolution (~2% at 662 keV) that allow for the separation and identification of discrete gamma-ray energies. This paper describes the methods being developed to analyze spectra and identify radioisotopes using measurements from a 24-detector system, a 42-detector planar array, and simulations from a large-scale HEMI system.