System, algorithm, and method using short pulse interrogation with neutrons to detect and identify matter

DWPI Title: Material detection system used in neutron prompted gamma emission analysis for detection of special nuclear material (SNM) and weapons of mass destruction (WDM), has signal processor that is set to determine presence of material in target
Abstract: A system, method, and algorithm for detecting and identifying special nuclear material (SNM) (including fissionable material), explosives, or drugs is disclosed. This material detection system relies on active interrogation of material using a short, intense neutron pulse, and characterization of the resulting prompt gamma response in two short time windows, the first concurrent with and the second immediately following the end of the neutron pulse, optionally subject to a total transit delay time of the neutrons from the neutron source to the target and from the target to the gamma detector. A high data rate analysis system implements data stream analysis and statistical correlations of the two short time window gamma responses to rapidly detect or identify SNM, explosives, or drugs. The duration of the neutron pulse is so short that minimal dose results. Various shields help to minimize the background signal falling on the gamma detector to improve sensitivity.
Use: Material detection system used in neutron prompted gamma emission analysis for detection of SNM and WDM, as well as other materials e.g., explosives and drugs.
Advantage: The system produces a much lower dose for the operators and the inspected items and requires much less time than the existing state-of-the-art detection systems. The method is much faster than the current state-of-the-art systems for the same purpose and provides a much lower dose to the item being interrogated and the system operators. The source, direct neutron, and field of view shields required to make sensitive measurements is reduced in size, resulting in less mass, for space or low-pressure environments. The experimental measurements are required for the short pulse interrogation using neutron (SPIN)-based material detection system to enable accurate inverse modeling and determination of materials. The improvement of material identification generally requires enhanced spectroscopy and preferably includes a combination of increased resolution and sensitivity to better resolve high energy gamma spectra. The detection is enhanced and the gamma signal from the target is readily detectable due to the signal-to-noise ratio being greater than approximately ten, at the optimum neutron flux. The increase in the gain of the photomultiplier tube (PMT) without saturation is permitted, yielding additional counts of the more numerous lower energy gammas, and resulting in better resolution spectra.
Novelty: The material detection system has a signal processor that is adapted to convert (435) the digital data stream into energy counts, to bin (440) the resultant energy counts, to create (445) a target spectrum based on the binned energy counts, to compare (450) the target spectrum to a background spectrum, and to determine a presence of a material in the target. The interrogation pulse of neutrons has a velocity vi. The neutron source is a distance d1 from the target resulting in a target transit time t1 =d1 /vi. The detection pulse has a velocity vd. The gamma detector is a distance d2 from the target resulting in a detector transit time t2 =d2 /vd. The first portion of the analog data stream corresponds to the first time window delayed by the total transit time from a start of the interrogation pulse. The second portion of the analog data stream corresponds to the second time window delayed by the total transit time from the end of the interrogation pulse.
Filed: 6/6/2019
Application Number: US16433576A
Tech ID: SD 14993.0
This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention.
Data from Derwent World Patents Index, provided by Clarivate
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