Expected Performance and Initial Results from the 2001 Mars Odyssey Gamma Ray Spectrometer (GRS) Instrument Suite
EGS XXVII General Assembly, Nice, 21-26, abstract #6602
Boynton, W.V., W.C. Feldman, I. Mitrofanov, J.I. Trombka, J.R.
Arnold, P.A.J. Englert, A.E.R. Metzger, C. Reedy, S.W. Squyres, C.
d'Uston, H. Wanke, J. Bruckner, D.M. Drake, L.G. Evans, R. Starr, C.
Shinohara, and F.S. Anderson
The Mars Odyssey Gamma -Ray Spectrometer (GRS) is a suite of three different instruments that share a common electronics box and complimentary scientific objectives. The instruments are the GRS proper, the Neutron Spectrometer (NS) and the High-Energy Neutron Detector (HEND). This instrument is a follow-on instrument to the GRS that was lost on the Mars Observer Mission in 1993. It is the last of the original seven Mars Observer instruments to get a Mars re-flight opportunity, and because of the long delay, it is the only one to be a new design. It is described in detail in Boynton et al. (2002). The NS was supplied by Los Alamos National Laboratory, the HEND was supplied by the Space Research Institute (Russia), and the central electronics box and the GRS proper was supplied by the University of Arizona, who also was responsible for the integration of the instrument suite. The GRS uses a cooled high-purity Ge detector to provide high spectral resolution, and it performed beautifully in flight. During cruise the resolution was 3.7 keV at 1332 keV (full-width at half maximum). This is substantially better than a good quality scintillation detector which would typically have a resolution of about 65 to 70 keV. We expect this excellent performance to allow us to determine the abundances of about 16 elements (Boynton et al. 1992). The two neutron systems have been collecting data since early January 2002, but the orbit and spacecraft orientation are not designed for quantitative data collection. We expect to be in the final mapping configuration in late February and will begin taking our science data at that time. Presently it is not clear when the orbit will be aligned such that the cooler on the gamma -ray detector will have sufficiently little sunlight on it that we can get cold enough to apply high voltage to the sensor and collect gamma data. We are hopeful to have interesting results to discuss at the meeting. References: Boynton, W. V. et al. (1992), J. Geophys. Res. 97:7681-7698. Boynton, W. V. et al. (2002), Space Sci. Rev. (In preparation).
For More Information: http://adsabs.harvard.edu/abs/2002EGSGA..27.6602B
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