A liquid xenon imaging telescope for gamma-ray astrophysics: Design and expected performance

Abstract A high resolution telescope for imaging cosmic γ-ray sources in the MeV region, with an angular resolution better than 0.5° is being developed as ballon-borne payload. The instrument consists of a 3-D liquid xenon TPC as γ-ray detector, coupled with a coded aperture at a distance of 1 meter. A study of the actual source distribution of the 1.809 MeV line from the decay of 26 Al and the 511 keV positron-electron annihilation line is among the scientific objectives, along with a search for new γ-ray sources. The telescope design parameters and expected minimum flux sensitivity to line and continuum radiation are presented. The unique capability of the LXe-TPC as a Compton Polarimeter is also discussed.