arXiv subjects

Ethan A. Klein

Publications and source records attributed to Ethan A. Klein.

3 recordsLinked to original sources

arXiv2026

Isotopic Measurements of SNM using a Portable Neutron Resonance Transmission System for Arms Control

Neutron Resonance Transmission Analysis (NRTA) was explored as an arms control verification approach to support potential future nuclear weapon limiting treaties. A compact and portable neutron Time of Flight (ToF) system was developed to enable proof-of-concept NRTA measurements of special nuclear material (SNM). Using a short 2-meter flight path, the NRT system is sensitive to cross-section resonances of isotopes such as 235U, 238U, 239Pu and 240Pu between 1-100 eV incident neutron energies due to their physical nuclear structure. The detected neutron ToF spectrum exhibits transmission dips at resonance energies that are characteristic of SNM isotopic composition in the inspected item. The proof-of-concept measurements of Highly Enriched Uranium (HEU), Depleted Uranium (DU), and Reactor Grade Plutonium (RGPu) confirmed the characteristic resonance features within two hours of data collection time. Analysis via the REFIT resonance fitting tool accurately predicted the 235U enrichment and Pu isotopic composition within 5% and 6% of the known values, respectively.

physics.ins-det↗

arXiv2021

Neutron Resonance Transmission Analysis with a Compact Deuterium-Tritium Neutron Generator

Neutron Resonance Transmission Analysis (NRTA) is a spectroscopic technique which uses the resonant absorption of neutrons in the epithermal range to infer the isotopic composition of an object. This spectroscopic technique has relevance in many traditional fields of science and nuclear security. NRTA in the past made use of large, expensive accelerator facilities to achieve precise neutron beams, significantly limiting its applicability. In this work we describe a series of NRTA experiments where we use a compact, low-cost deuterium-tritium (DT) neutron generator to produce short neutron beams (2.6~m) along with a $^6$Li-glass neutron detector. The time-of-flight spectral data from five elements -- silver, cadmium, tungsten, indium, and $^{238}$U -- clearly show the corresponding absorption lines in the 1-30 eV range. The experiments show the applicability of NRTA in this simplified configuration, and prove the feasibility of this compact and low-cost approach. This could significantly broaden the applicability of NRTA, and make it practical and applicable in many fields, such as material science, nuclear engineering, and arms control.

physics.ins-det↗

arXiv2020

Feasibility study of a compact Neutron Resonance Transmission Analysis instrument

Neutron Resonance Transmission Analysis (NRTA) uses resonant absorption of neutrons to infer the absolute isotopic composition of a target object, enabling applications in a broad range of fields such as archaeology, materials analysis of nuclear fuel, and arms control treaty verification. In the past, NRTA involved large user facilities and complex detector systems. However, recent advances in the intensity of compact neutron sources have made compact neutron imaging designs increasingly feasible. This work describes the Monte Carlo (MC) based design of a compact epithermal NRTA radiographic instrument which uses a moderated, compact deuterium-tritium (DT) neutron source and an epithermal neutron detector. Such an instrument would have a wide range of applications, and would be especially impactful for such scenarios as nuclear inspection and arms control verification exercises, where system cost and mobility may be of critical importance. The MC simulations presented in this work demonstrate accurate time-of-flight (TOF) reconstructions for transmitted neutron energies, capable of differentiating isotopic compositions of nuclear material with high levels of accuracy. A new generation of miniaturized and increasingly more intense neutron sources will allow this technique to achieve measurements with greater precision and speed, with significant impact on a variety of engineering and societal problems.

physics.ins-det↗