Work

Improved contraband detection using an experimentally optimized neutron active interrogation pulse structure

Year: 2025

Type: article

Abstract: Neutron active interrogation is an approach that can identify concealed contraband in cargo, for which chlorine detection can be indicative. We used a pulsed deuterium-deuterium neutron generator to induce chlorine capture gamma rays and measured this signature with a NaI(Tl) inorganic scintillator and organic scintillators analyzed with maximum likelihood estimation-maximization-based spectral reconstruction. The time profile of neutron emission from the neutron generator was also measured using an organic scintillator. We evaluate the signal intensity and signal-to-background ratio for the chlorine gamma-ray signatures for various neutron generator pulse lengths. We demonstrate that decreasing the pulse length can increase the chlorine signal intensity, thereby enhancing sensitivity to chlorine-containing contraband. For example, we show that by decreasing the neutron generator duty factor from 50% to 5%, the chlorine signal intensity measured with NaI(Tl) during the time region between neutron pulses increases from 44.7 ± 0.3% of the signal intensity without time gating to 99.1 ± 0.3% of the signal intensity without time gating. We also show that the signal-to-background ratio for chlorine signatures does not decrease by reducing pulse width.

Source: Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment

DOI: 10.1016/j.nima.2025.171157

Authors: Colton Graham, Junwoo Bae, Shaun Clarke, Sara Pozzi, Igor Jovanovic

Institution: University of Michigan

Language: English

Topic: Nuclear Physics and Applications

Subfield: Radiation

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,620

Funders: U.S. Department of Homeland Security, National Nuclear Security Administration