Presentation Global dose distributions of Lunar neutrons and gamma-rays obtained by the Kaguya gamma-ray spectrometer

N.Hasebe  ,  R.Hayashida  ,  K.Yoshida  ,  M.Naito  ,  H.Kusano  ,  H.Nagaoka  ,  C.Furuuchi  ,  M.Hareyama  ,  S.Kodaira  ,  J.Matias-Lopes

The Kaguya Gamma-Ray Spectrometer (KGRS) onboard the Japanese lunar polar orbiter "Kaguya" has measured the gamma rays emitted from the global lunar surface during the period Feb. 10 to May 28, 2009. The gamma-rays and neutrons are genetrated by nuclear interaction of Galactic Cosmic Rays (GCRs) with the Moon surface materuals. Using these gamma-ray and neutron data measured by the KGRsm the global maps of ambient doseequivalents due to lunar neutrons and gamma-rays were obtained. The mean doses from neutrons and gamma-rays on the lunar surface were 70 mSv/yr and 3mSv/yr, respectively. The dose equivalents are found to be high on mare regions, especially western Mare, which is attributed to the correlation with the enhancement of Fe and Ti and depletion of Ca and Al. The doses are also enhanced in the Eastern mare region. The doses in highlands are much lower than 70 mSv/yr because the elements are depleted in Fe and Ti and enhanced in Ca and Ai. Especially, the neutron dose, occupying about 10% of the total ambient dose equivalent due to primary GCR particles, is considerable contribution for radiation safety and protection in up-coming manned mission on the Moon.
The 20th Workshop on Radiation Monitoring for the International Space Station

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