A directional gamma-ray telescope using coded aperture techniques
Abstract
A directional detector for γ-ray astronomy has been developed to image sources in the energy range 0.1 to 5 MeV. An array of 35 gain stabilized bismuth germanate detectors, together with a coded aperture mask based on a Uniformly Redundant Array (URA), allows imaging in 4° square sky bins over a 16° X 24° field-of-view. The position of a strong point source, such as the Crab Nebula, can be determined to within ≲1°. A complementary “anti-mask” greatly reduces systematic effects arising from non-uniform background rates amongst the detectors. The telescope has an effective area of 190 cm2 and an energy resolution of 19.5% FWHM at 662 keV. Results of laboratory tests of the imaging system, including the ability to image multiple sources, uniformity of response over the field-of-view, and the effect of the “anti-mask”, are in good agreement with computer simulations. Features of the flight detector system are described and results of laboratory tests and computer simulations are reviewed. A balloon flight of the telescope is planned for the fall of 1982.
Department
Physics
Publication Date
1983
Journal Title
Advances in Space Research
Publisher
Elsevier
Digital Object Identifier (DOI)
10.1016/0273-1177(83)90017-0
Document Type
Article
Recommended Citation
M.L. McConnell, P.P. Dunphy, D.J. Forrest, and E.L. Chupp, 1983, Adv. Space Research, 3, No. 4, 105.