Open AccessRadiation dose and its protection in the Moon from galactic cosmic rays and solar energetic particles: at the lunar surface and in a lava tube
Author(s) -
Masanori Naito,
Nobuyuki Hasebe,
Mana Shikishima,
Yoshiharu Amano,
Junichi Haruyama,
José A. Matias-Lopes,
Kyeong Ja Kim,
Satoshi Kodaira
Publication year - 2020
Publication title -
journal of radiological protection
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.471
H-Index - 46
eISSN - 1361-6498
pISSN - 0952-4746
DOI - 10.1088/1361-6498/abb120
Subject(s) - cosmic ray , solar energetic particles , lunar soil , equivalent dose , radiation , physics , health threat from cosmic rays , lava , monte carlo method , astrobiology , environmental science , astrophysics , geology , solar wind , magnetic field , optics , coronal mass ejection , quantum mechanics , statistics , mathematics , volcano , seismology
The lunar surface is directly and continuously exposed to Galactic Cosmic ray (GCR) particles and Solar energetic particles (SEPs) due to the lack of atmosphere and lunar magnetic field. These charged particles interact with the lunar surface materials producing secondary radiations such as neutrons and gamma rays. In a departure from precise GCR and SEP data, we estimated the effective dose equivalent at the lunar surface and in a lunar lava tube in this paper by using PHITS, a Monte Carlo simulation tool. The effective dose equivalent due to GCR particles at the lunar surface reached 416.0 mSv yr -1 and that due to SEPs reached 2190 mSv/event. On the other hand, the vertical hole of the lava tube provides significant radiation protection. The exposure by GCR particles at the bottom of the vertical hole with a depth of 43 m was found to be below 30 mSv yr -1 while inside a horizontal lava tube, the value was less than 1 mSv yr -1 which is the reference value for human exposure on the Earth. We expect that the lunar holes will be useful components in the practical design of a lunar base to reduce radiation risk and to expand mission terms.