Image Restoration of Lunar Neutron Albedo Maps for the Lunar Explora- Tion Neutron Detector (lend)

Introduction: The Lunar Exploration Neutron Detector (LEND) onboard the Lunar Reconnaissance Orbiter (LRO) will measure the flux of neutrons from the Moon, which are produced by the continuous and isotropic cosmic ray bombardment of the lunar surface. When cosmic rays hit the regolith, they release high-energy neutrons that are then slowed down and absorbed by the nuclei of elements in the rego-lith. However, not all neutrons are captured by the soil and many escape, which creates a leakage of flux of neutrons detectable by the LEND instrument. [Vondrak, 2007] Orbital measurements of the neutron energies are used to infer the geochemistry of the lunar regolith. The main goal of LEND is to observe hydrogen, which has a significant impact on the neutron leakage energies and is detectable in concentrations greater than 100 pm. [Mitrofanov, 2008] The lunar surface neutron flux rates are low and variable as a function of cosmic ray induced activation energies, soil composition and geo-chemistry. It is estimated that the collimator of LEND will collect approximately .88 counts/second with a field of view (FOV) at a 50 kilometer altitude, spanning 5.6 kilometer full width at half maximum (FWHM), across the lunar surface. Primary science mission will cover 382 days with a possible extension for a second year of science mapping. Problem: Due to the mission mandated polar obit, accumulated spatial coverage will be high at the poles and decrease as a function of latitude. The process of detecting and accumulating neutrons is a Poisson process and the spatial distribution of signals will be degraded by pixel statistical uncertainties and blurred by the LEND collimator. This process degrades the spatial resolutions of mapped neutron signals. Methods for image restoration of planetary neutron albedo maps have been proposed by [Elphic, 2007] and [Lawrence, 2006] for analysis of Lunar Prospector Neutron data. This research evaluates several methods to determine both applicability and configuration of methods. Objective: To determine the optimal image restoration technique for restoring the hydrogen lunar albedo maps for LEND and to identify ap