MARGIE — minute of arc resolution hard X-ray/gamma ray imaging telescope for an ultra long duration balloon mission

MARGIE (Minute of Arc Resolution Gamma ray Imaging Experiment) is proposed to be a sensitive, large field-of-view, high angular resolution, hard X-ray/gamma ray (20–511 keV) telescope capable of observing gamma ray bursts and point sources with <1′ resolution on a 100 day Ultra Long Duration Balloon (ULDB) mission. MARGIE will be designed to take full advantage of the weight, power, and telemetry capabilities appropriate for a ULDB mission. The current instrument design consists of five coded aperture γ-ray telescopes: a central telescope with 1892 cmb of detector area, 1.9′ angular resolution, and 8.3° half-angle field of view (FOV); and four side-looking telescopes, each with 1945 cmb detector area, 3.8′ resolution, and 26.1° FOV. The five γ-ray telescopes will be surrounded by 10e cmb of 1 cm thick NaI active anticoincidence shields designed both to provide shielding from background and to provide additional sensitive detector area for faint γ-ray bursts. The total instrument mass is 950 kg (science, not including NSBF electronics, ballast, etc.). The total instrument power requirement is 760 W.