A Thick Anger Camera for Gamma-Ray Astronomy

The NaI(Tl) Anger camera is a natural candidate for a position sensitive detector in imaging of astrophysical ¿-ray sources. Here we present laboratory measurements of the response of a relatively thick (5.1 cm) NaI(Tl) Anger camera designed for coded aperture imaging in the 50 keV to 2 MeV energy range. We obtained a position resolution of 10.5 mm FWHM at 122 keV and 6.3 mm FWHM at 662 keV. The energy resolution was 7% FWHM at 662 keV. We discuss the ability of the detector to resolve the depth of the ¿-ray interaction and the use of this depth resolution to reduce back-incident and internal background.