Complexities of gamma-ray line intensities from the lunar surface

Naoyuki Yamashita*, Nobuyuki Hasebe, Takashi Miyachi, Masanori Kobayashi, Osamu Okudaira, Shingo Kobayashi, Takeshi Ishizaki, Kunitomo Sakurai, Mitsuhiro Miyajima, Robert C. Reedy, Claude d'Uston, Sylvestre Maurice, Olivier Gasnault

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    22 Citations (Scopus)


    Assuming different abundances of the Apollo lunar soil samples and the average spectrum of galactic cosmic ray protons, energy spectra of neutrons and gamma rays and emission rates of gamma-ray lines from major elements have been estimated by using the reviewed Monte Carlo simulation library Geant4 and nuclear data. Previously, such libraries were not able to reproduce gamma-ray lines properly for the planetary application. Results clearly show that the emission rate of gamma rays heavily depends not only on the chemical abundance but also neutron flux within the lunar subsurface. While the intensities of gamma-ray lines are mostly proportional to elemental abundances, the intensity per unit elemental abundance can vary. Such a complex correlation is attributed to the change in neutron flux within the lunar subsurface and petrological restriction of elemental variation.

    Original languageEnglish
    Pages (from-to)313-319
    Number of pages7
    JournalEarth, Planets and Space
    Issue number4
    Publication statusPublished - 2008


    • Gamma ray
    • GRS
    • Lunar and planetary spectroscopy
    • Moon
    • Neutron
    • SELENE

    ASJC Scopus subject areas

    • Earth and Planetary Sciences (miscellaneous)
    • Geology
    • Space and Planetary Science


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