Use of mercuric iodide X-ray detectors with alpha backscattering spectrometers for space applications

The authors present X-ray fluorescence (XRF) spectra of different extraterrestrial samples taken with a mercuric iodide (HgI/sub 2/) spectrometer inserted into all alpha backscattering instrument identical to that used in the Soviet Phobos mission. The results obtained with the HgI/sub 2 /ambient temperature detector are compared with those obtained using all Si(Li) cryogenically cooled detector. Efforts to design all optimized instrument for space application are also described. The results presented indicate that the energy resolution and sensitivity of HgI/sub 2/ detectors are adequate to meet the performance needs of a number of proposed space applications, particularly those in which cooled silicon X-ray detectors are impractical or even not usable, such as for the target science programs on geoscience opportunities for lunar surface, Mars surface, and other comet and planetary missions being planned by NASA and ESA.<
>