A Fluorescent Gated Imaging Gas Scintillation Specftroeter for High Energy X-Ray Astronomy

Results are presented on the development of a position sensitive gas scintillation proportional counter for use in high energy X-ray astronomy. This detector has a higher background rejection efficiency and a better energy resolution above 35 keV than conventional gas scintillators, gas proportional counters and crystal scintillators. These improvements arise directly fran the application of a discrimination technique which makes use of the detection of the fluorescent Xenon K shell photon emitted in most interactions involving the photoabsorption of genuine X-rays with energies greater than the K shell binding energy. Detectors incorporating this technique, and also having a position sensing capability to reject the induced Compton electron background fran the detector walls, will provide unique information on the spectral characteristics of cosmic X-ray sources. Such characteristics include high energy cyclotron lines fran neutron stars. The inherent imaging properties of these detectors when operated at high X-ray energies are also investigated. Such a detector when used in conjunction with a coded aperture mask will form a camera with an imaging capability of a few arc minutes at X-ray energies beyond the practical range of grazing incidence telescopes.