| 摘要 |
<p>A gamma -ray telescope that comprises a dislocation-free single crystal. Typical crystals include silicon and germanium, for example. The crystal is surrounded by an active shield that functions as an anticoincidence counter and a gamma -ray detector is disposed adjacent the crystal in order to detect received gamma -rays. The gamma -ray detector comprises an imaging proportional counter, scintillation counter, or a gamma -ray detecting charge coupled device, for example. The gamma -ray detector is based on the Borrmann effect, which is the anomalous transmission of gamma -rays through dislocation free single crystals at the Bragg angle. For extended sources, data processing is provided to separate the directional and wavelength dependence of the intensity variation. The gamma -ray telescope has angular resolution of at least one arc second and may have an effective aperture of several square meters. Reduction in background radiation, which is essentially determined by the crystal thickness, may be made quite large, greater than 10<1><2>. Consequently, the use of the present invention makes it possible to detect a weak gamma -ray source even in the presence of a large isotropic background.</p> |
