Determining the absolute abundances of natural radioactive elements on the lunar surface by the kaguya gamma-ray spectrometer

S. Kobayashi, Nobuyuki Hasebe, E. Shibamura, O. Okudaira, M. Kobayashi, N. Yamashita, Y. Karouji, M. Hareyama, K. Hayatsu, C. D'Uston, S. Maurice, O. Gasnault, O. Forni, B. Diez, R. C. Reedy, K. J. Kim

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    37 Citations (Scopus)

    Abstract

    The Kaguya gamma-ray spectrometer (KGRS) has great potential to precisely determine the absolute abundances of natural radioactive elements K, Th and U on the lunar surface because of its excellent spectroscopic performance. In order to achieve the best performance of the KGRS, it is important to know the spatial response function (SRF) that describes the directional sensitivity of the KGRS. The SRF is derived by a series of Monte Carlo simulations of gamma-ray transport in the sensor of the KGRS using the full-fledged simulation model of the KGRS, and is studied in detail. In this paper, the method for deriving absolute abundance of natural radioactive elements based on the SRF is described for the analysis of KGRS data, which is also applicable to any gamma-ray remote sensings. In the preliminary analysis of KGRS data, we determined the absolute abundances of K and Th on the lunar surface without using any previous knowledge of chemical information gained from Apollo samples, lunar meteorites and/or previous lunar remote sensings. The results are compared with the previous measurements and the difference and the correspondence are discussed. Future detailed analysis of KGRS data will provide new and more precise maps of K, Th and U on the lunar surface.

    Original languageEnglish
    Pages (from-to)193-218
    Number of pages26
    JournalSpace Science Reviews
    Volume154
    Issue number1-4
    DOIs
    Publication statusPublished - 2010 Jul

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    Keywords

    • Gamma-ray spectrometer
    • K
    • Moon
    • Natural radioactive elements
    • SELENE (Kaguya)
    • Spatial response function
    • Th
    • U

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

    Cite this

    Kobayashi, S., Hasebe, N., Shibamura, E., Okudaira, O., Kobayashi, M., Yamashita, N., Karouji, Y., Hareyama, M., Hayatsu, K., D'Uston, C., Maurice, S., Gasnault, O., Forni, O., Diez, B., Reedy, R. C., & Kim, K. J. (2010). Determining the absolute abundances of natural radioactive elements on the lunar surface by the kaguya gamma-ray spectrometer. Space Science Reviews, 154(1-4), 193-218. https://doi.org/10.1007/s11214-010-9650-2