High Sensitivity Imaging of Soft γ-Rays Using Bragg Concentrators

Abstract

An imaging telescope, capable of focussing soft γ-rays in the energy range between 300 keV and 2 MeV has been studied. This energy range encompasses many of the nuclear γ-ray lines of astrophysical interest, and, not the least, the electron-positron annihilation line and its wings. The study concludes, that a Bragg-concentrator system may provide order of magnitude increases both in sensitivity and in source localization compared to the INTEGRAL, instrumentation, while at the same time allowing some rudimentary imaging over fields of about 10 arcminutes diameter. The feasibility of this concept still remains to be proven, however, since the telescope dimensions are very large, with focal lengths of the order 50 m.