Experimental results obtained with the positron-annihilation-radiation telescope of the Toulouse-Argonne collaboration

Abstract

We present laboratory measurements obtained with a ground-based prototype of a focusing positron-annihilation-radiation telescope developed by the Toulouse-Argonne collaboration. This balloon-borne telescope has been designed to collect 511-keV photons with an extremely low instrumental background. The telescope features a Laue diffraction lens and a detector module containing a small array of germanium detectors. It will provide a combination of high spatial and energy resolution (15 arc sec and 2 keV, respectively) with a sensitivity of -3x10-5 photons cm-2s-1. These features will allow us to resolve a possible narrow 511-keV line both energetically and spatially within a Galactic center “microquasar” or in other broad-class annihilators.