Distributions of K and Th on the moon: The initial results from observations by selene GRS

Yuzuru Karouji*, Nobuyuki Hasebe, Osamu Okudaira, Naoyuki Yamashita, Shingo Kobayashi, Makoto Hareyama, Takashi Miyachi, Kodaira Satoshi, Kazuya Iwabuchi, Kanako Hayatsu, Shinpei Nemoto, Yuko Takeda, Koichi Tsukada, Hiroshi Nagaoka, Masanori Kobayasi, Eido Shibamura, Mitsuru Ebihara, Takeshi Hihara, Tomoko Arai, Takamitsu SugiharaHiroshi Takeda, Claude D’Uston, Sylvestre Maurice, Olivier Gasnault, Olivier Forni, Benedicte Diez, Robert C. Reedy, Kyeong J. Kim, Takeshi Takashima, Yuichi Iijima, Hisashi Otake

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


The high precision gamma-ray spectrometer (GRS) onboard the Japanese lunar explorer, SELENE (KAGUYA) consists of a large Ge crystal as the main detector and massive BGO and plastic scintillators as anticoincidence detectors. After a series of initial health checks, it started regular observation officially on December 21, 2007. Energy spectra of lunar gamma rays were obtained by GRS with very good energy resolution being 0.6% at 1.46MeV over the lunar surface. Many peaks of gamma rays from major elements and natural radioactive elements in the lunar surface have been observed. Individual gamma-ray lines emitted from the lunar surface have been identified. Here, we report the initial results obtained practically during the period from December 14, 2007 to February 17, 2008. Global maps of K and Th gamma-ray intensities are reported using count rates in several energy bands.

Original languageEnglish
Title of host publicationAdvances in Geosciences
Subtitle of host publicationVolume 19: Planetary Science (PS)
PublisherWorld Scientific Publishing Co.
Number of pages14
ISBN (Electronic)9789812838162
ISBN (Print)9812838155, 9789812838155
Publication statusPublished - 2010 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Earth and Planetary Sciences(all)


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