The spatial distribution of polar hydrogen deposits on the Moon

TL;DR

This paper presents an improved map of lunar polar hydrogen deposits using a novel image reconstruction algorithm on neutron data, indicating concentrated hydrogen in cold traps likely as volatiles or solar wind protons.

Contribution

Introduces a pixon-based deconvolution method to enhance lunar hydrogen mapping from neutron data, revealing high concentration in cold traps.

Findings

Hydrogen is concentrated in lunar cold traps up to 1 wt% water-equivalent.

Hydrogen likely exists as volatile compounds or solar wind protons.

The method improves spatial resolution of lunar hydrogen distribution.

Abstract

A new analysis of the Lunar Prospector epithermal neutron data is presented, providing an improved map of the distribution of hydrogen near to the lunar poles. This is achieved using a specially developed pixon image reconstruction algorithm to deconvolve the instrumental response of the Lunar Prospector's neutron spectrometer from the observed data, while simultaneously suppressing the statistical noise. The results show that these data alone require the hydrogen to be concentrated into the cold traps at up to 1 wt% water-equivalent hydrogen. This combination of localisation and high concentration suggests that the hydrogen is present either in the form of a volatile compound or as solar wind protons implanted into small regolith grains.