Precision measurements of neutron inelastic scattering cross sections for planetary nuclear spectroscopy
ORAL
Abstract
Measuring the elemental composition of planetary objects improves our understanding of the formation and evolution of our solar system. Additionally, localized measurements can inform about potential hazards, resources, and biosignatures that can revolutionize human space exploration activities. Orbital and in-situ neutron and gamma spectrometers have been used in the past to measure the elemental composition of asteroids, moons, and planets, while others are currently being designed and built for future missions, such as Dragonfly.
The quality of the data obtained by spectrometers of this kind is limited, in part, by the current state of nuclear databases, specifically capture (n,g) and inelastic scattering (n,n’g) cross sections. The latter has wider gaps and inconsistencies across the board because of several reasons including the lack of dedicated facilities and equipment that can produce energy-selective high-energy neutrons with low gamma ray background from scattered and thermal neutrons.
Associated Particle Imaging (API) is an attractive technique to measure inelastic scattering cross sections with high precision, which addresses some of the concerns outlined above for the following reasons:
1) An API deuterium-tritium (DT) neutron generator is a well characterized, quasi-monoenergetic 14.1 MeV neutron source.
2) Time tagging allows for the selective detection of prompt gamma emission only; ideal for measurements of neutron inelastic scattering followed by gamma emission.
3) Spatial resolution and 3D imaging allows for significant gamma background/contamination suppression when the irradiated sample is well isolated.
We will present and discuss initial results obtained from an experiment carried out with an API system at Lawrence Berkeley National Laboratory.
The quality of the data obtained by spectrometers of this kind is limited, in part, by the current state of nuclear databases, specifically capture (n,g) and inelastic scattering (n,n’g) cross sections. The latter has wider gaps and inconsistencies across the board because of several reasons including the lack of dedicated facilities and equipment that can produce energy-selective high-energy neutrons with low gamma ray background from scattered and thermal neutrons.
Associated Particle Imaging (API) is an attractive technique to measure inelastic scattering cross sections with high precision, which addresses some of the concerns outlined above for the following reasons:
1) An API deuterium-tritium (DT) neutron generator is a well characterized, quasi-monoenergetic 14.1 MeV neutron source.
2) Time tagging allows for the selective detection of prompt gamma emission only; ideal for measurements of neutron inelastic scattering followed by gamma emission.
3) Spatial resolution and 3D imaging allows for significant gamma background/contamination suppression when the irradiated sample is well isolated.
We will present and discuss initial results obtained from an experiment carried out with an API system at Lawrence Berkeley National Laboratory.
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Presenters
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Mauricio Ayllon Unzueta
NASA Goddard Space Flight Center
Authors
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Mauricio Ayllon Unzueta
NASA Goddard Space Flight Center
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Patrick N Peplowski
Applied Phys Lab/JHU
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Jack Wilson
The Johns Hopkins University Applied Physics Laboratory
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Ann M Parsons
NASA Goddard Space Flight Center
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Arun Persaud
Lawrence Berkeley National Laboratory