High Throughput Non-Dispersive Hard X-Ray Spectrograph with Angular Resolution for Cosmic Bursts, Transients, and Sources

A concept for a high throughput spectrometer for the 35-150 keV band is described. The energy resolution is only a factor of 2 to 4 inferior to germanium detectors, while the effective area is much larger. An effective area of 103 cm2 per unit should be easily attainable and 104 cm2 does not seem to be unreasonable. Minimal shielding, no cooling, and no external guard counters are needed, making the instrument rather light weight for its effective area. The sensitivity of this spectrometer should be larger than any other type in balloon observations of hard X-ray cyclotron lines and putative Ti44 nucleosynthesis lines in young supernova remnants. The detector is based upon a position sensitive proportional counter, and it may be used in conjunction with a very wide field coded aperture mask to provide both spectra and precise celestial locations for unidentified sources, transients, and gamma ray bursts. By means of a Monte Carlo calculation, the performance of the spectrometer in a number of balloon experiments has been simulated. Results are very encouraging and suggest considerable improvement over previous measurements.