The Imaging Liquid Xenon-Coded Aperture Telescope (LXe-CAT)

We describe a unique γ-ray imaging telescope operating in the energy range 0.3-10 MeV. The basic element of the telescope is a liquid xenon time projection chamber (LXe-TPC) as γ-ray spectrometer and 3-D imager. Location and energy analysis of multiple Compton scattering events in the chamber will permit a reconstruction of the incoming γ-ray direction, thus allowing a significant reduction of background. A 10-liter LXe-TPC prototype, with 400 cm2 active area and 5 cm drift gap has been built and is currently being tested with γ-ray sources in the laboratory. Initial results are presented. The combination of the LXe-TPC with a coded aperture (LXe-CAT), results in a telescope with superior detection efficiency, angular and energy resolution, and excellent background rejection capability. Simulation results on the instrument’s ability to image the Crab Nebula region in a balloon observation are presented, as well as to image the 1.809 MeV 26A1 distribution from the Vela region, in a satellite observation.