A compact, low-power epithermal neutron counter for lunar water detection

Fuente: arXiv
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Main Authors: Cuevas-Zepeda, Julian, Alpine, Phoenix, Cervantes-Vergara, Brenda A., Chavez, Claudio, Estrada, Juan, Etzion, Erez, Fernandez-Moroni, Guillermo, Saffold, Nathan, Sofo-Haro, Miguel, Tiffenberg, Javier
Format: Preprint
Published: 2025
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author Cuevas-Zepeda, Julian
Alpine, Phoenix
Cervantes-Vergara, Brenda A.
Chavez, Claudio
Estrada, Juan
Etzion, Erez
Fernandez-Moroni, Guillermo
Saffold, Nathan
Sofo-Haro, Miguel
Tiffenberg, Javier
author_facet Cuevas-Zepeda, Julian
Alpine, Phoenix
Cervantes-Vergara, Brenda A.
Chavez, Claudio
Estrada, Juan
Etzion, Erez
Fernandez-Moroni, Guillermo
Saffold, Nathan
Sofo-Haro, Miguel
Tiffenberg, Javier
contents The detection and characterization of lunar water are critical for enabling sustainable human and robotic exploration of the Moon. Orbital neutron spectrometers, such as instruments on Lunar Prospector and the Lunar Reconnaissance Orbiter, have revealed hydrogen-rich regions near the poles but are limited by coarse spatial resolution and low counting efficiency. We present a compact, lightweight, and low-power epithermal neutron detector based on boron-coated silicon imagers, designed to probe subsurface hydrogen at decimeter scales from mobile platforms such as lunar rovers. This instrument leverages the high neutron capture cross-section of $^{10}$B to convert epithermal neutrons into detectable $α$ and $^{7}$Li ions in a fully-depleted silicon imager, providing a unique event topology to identify neutrons while suppressing backgrounds. Monte Carlo simulations demonstrate that a 3 $μ$m boron layer achieves optimal neutron detection efficiency, further enhanced with polyethylene moderation to improve sensitivity to the 0.4 eV-500 keV epithermal energy range. For a 10 cm$^2$ active area, the detector achieves sensitivity to H$_2$O weight fractions as low as 0.01 wt % in a 15 minute measurement. This scalable, portable, low-mass design is well-suited for integration into upcoming Artemis and commercial lunar rovers, providing a transformative capability for in-situ resource prospecting and ground-truth validation of orbital measurements.
format Preprint
id arxiv_https___arxiv_org_abs_2509_04367
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A compact, low-power epithermal neutron counter for lunar water detection
Cuevas-Zepeda, Julian
Alpine, Phoenix
Cervantes-Vergara, Brenda A.
Chavez, Claudio
Estrada, Juan
Etzion, Erez
Fernandez-Moroni, Guillermo
Saffold, Nathan
Sofo-Haro, Miguel
Tiffenberg, Javier
Instrumentation and Detectors
Instrumentation and Methods for Astrophysics
The detection and characterization of lunar water are critical for enabling sustainable human and robotic exploration of the Moon. Orbital neutron spectrometers, such as instruments on Lunar Prospector and the Lunar Reconnaissance Orbiter, have revealed hydrogen-rich regions near the poles but are limited by coarse spatial resolution and low counting efficiency. We present a compact, lightweight, and low-power epithermal neutron detector based on boron-coated silicon imagers, designed to probe subsurface hydrogen at decimeter scales from mobile platforms such as lunar rovers. This instrument leverages the high neutron capture cross-section of $^{10}$B to convert epithermal neutrons into detectable $α$ and $^{7}$Li ions in a fully-depleted silicon imager, providing a unique event topology to identify neutrons while suppressing backgrounds. Monte Carlo simulations demonstrate that a 3 $μ$m boron layer achieves optimal neutron detection efficiency, further enhanced with polyethylene moderation to improve sensitivity to the 0.4 eV-500 keV epithermal energy range. For a 10 cm$^2$ active area, the detector achieves sensitivity to H$_2$O weight fractions as low as 0.01 wt % in a 15 minute measurement. This scalable, portable, low-mass design is well-suited for integration into upcoming Artemis and commercial lunar rovers, providing a transformative capability for in-situ resource prospecting and ground-truth validation of orbital measurements.
title A compact, low-power epithermal neutron counter for lunar water detection
topic Instrumentation and Detectors
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2509.04367