Abstract

Lunar volatiles, including water ice, are considered to be preserved in cold traps or buried beneath the surface layer near the poles. Understanding their distribution and abundance is critical for advancing knowledge of lunar evolution and for supporting future exploration activities. Neutron and gamma-ray spectroscopy provide key tools for this purpose, as subsurface hydrogen abundance can be inferred to depths of up to 1 m from measurements of neutron leakage flux and gamma-ray continuum flux from the Moon. In this seminar, I will discuss the lunar leakage neutron and gamma continuum flux induced by galactic cosmic rays interacting with the lunar surface, as well as their dependence on subsurface hydrogen abundances, using Monte Carlo simulations. The effects of temperature and compositional variation on neutron leakage flux are examined. The sensitivity of the leakage neutron intensity to the depth profile of subsurface water ice within the top 1 m of soil will also be discussed.