The All-Sky Compton Imager (ASCI) is a mission concept for MeV Gamma-Ray astronomy. It consists of a compact array of cross-strip germanium detectors, shielded only by a plastic anticoicidence, and weighting less than 100 kg. Situated on a deployable structure at a distance of 10 m from the spacecraft orbiting at L2 or in a HEO, the ASCI not only avoids albedo- and spacecraft-induced background, but it benefits from a continuous all-sky exposure. The modest effective area is more than compensated by the 4 π field-of-view. Despite its small size, ASCI's γ-ray line sensitivity after its nominal lifetime of 3 years is ~ 10^-6 ph cm^-2 s^-1 at 1 MeV for every γ-ray source in the sky. With its high spectral and 3-D spatial resolution, the ASCI will perform sensitive γray spectroscopy and polarimetry in the energy band 100 keV-10 MeV. The All-Sky Compton Imager is particularly well suited to the task of measuring the Cosmic Gamma-Ray Background – and simultaneously covering the wide range of science topics in gamma-ray astronomy.

Date Published: 24 July 2014
PDF: 7 pages
Proc. SPIE 9144, Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, 91440H (24 July 2014); doi: 10.1117/12.2057535

Published in SPIE Proceedings Vol. 9144:
Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray
Tadayuki Takahashi; Jan-Willem A. den Herder; Mark Bautz, Editor(s)