Multi-Signature Nuclear Material Detection System

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Solution Overview

Problem

Conventional nuclear material detection systems rely heavily on delayed-neutron signatures, which are weak and attenuated in hydrogenous and metallic cargos, limiting their efficacy, and often blind detectors due to simultaneous production with probing radiation, necessitating a more robust multi-signature detection approach.

Innovation Solution

A system employing a radiation source that simultaneously produces X-rays and neutrons to induce fission in nuclear material, using a combination of threshold-activation detectors, plastic scintillator detectors, and moderated He-3 detectors to detect multiple fission signatures, including prompt neutrons, delayed-gamma rays, and delayed neutrons, positioned to capture signatures at various angles and times to overcome detection limitations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If delayed-neutron detection is used, then nuclear material can be identified with high reliability, but the detection sensitivity is severely reduced due to low signal abundance and attenuation

Engineering Contradiction:
Improvenuclear material identification reliabilityVSAvoiddetection sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent combines multiple detection methods (delayed-neutron detection, prompt-gamma detection, and passive radiation detection) into a single integrated system. This merging of detection approaches allows the system to maintain high reliability through multiple identification pathways while improving overall detection sensitivity by leveraging the complementary strengths of each method across different cargo types.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If prompt-neutron detection is used, then detection sensitivity is improved due to higher signal abundance, but detectors are blinded by simultaneous production with probing radiation

Engineering Contradiction:
Improvedetection sensitivityVSAvoiddetector functionality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary discrimination by detecting prompt-gamma rays before attempting to detect prompt neutrons. The prompt-gamma signal serves as an early indicator of nuclear material presence, allowing the system to trigger enhanced detection modes or adjust detector settings in advance, thereby improving sensitivity without compromising reliability from blinding effects.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces prompt-gamma detection as an intermediary signal that mediates between the probing radiation and prompt-neutron detection. The gamma-ray signal acts as a precursor that helps distinguish nuclear material signatures from background radiation, enabling subsequent neutron detection to proceed with improved reliability despite the challenging radiation environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple probing radiation types are used, then inspection sensitivity is improved across diverse cargo types, but system complexity increases

Engineering Contradiction:
Improveinspection sensitivityVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The inspection system is designed with multi-functional capability to handle diverse cargo types using a unified approach. The system can automatically select and switch between different probing radiation types (neutrons, X-rays, gamma rays) and detection methods based on the detected cargo characteristics, providing universal inspection sensitivity across maritime, air, and land transport without requiring separate specialized systems for each cargo type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This multi-signature detection system enhances sensitivity and reliability by utilizing the complementary penetration of X-rays and neutrons across various cargo types, allowing for effective detection of nuclear material despite attenuation and blinding effects.

Implementation Method 1

conventionally, nuclear material is detected by exposing a container to radiation, such as X-ray radiation or neutrons, and inducing fission by interaction of the radiation with the nuclear material, referred to as photo-fission or neutron fission, respectively

Methodology Applied
Scientific EffectPhoto-fission: Nuclear Fission

Implementation Method 2

inducing fission by interaction of the radiation with the nuclear material, referred to as photo-fission or neutron fission, respectively

Methodology Applied
Scientific EffectNeutron fission: Nuclear Fission

Implementation Method 3

a first detector wherein said first detector type is a threshold-activation detector

Methodology Applied
Scientific EffectNeutron activation: Nuclear Fission

Implementation Method 4

a second detector wherein said second detector type is at least one of a threshold- activation detector, a plastic scintillator detector, a moderated He-3 detector, or a He-3 equivalent replacement detector

Methodology Applied
Scientific EffectScintillation: Scintillation

Data Source

PatentEP2539902B1Systems and methods for detecting nuclear material
Publication Date: 2020.02.19 RAPISCAN SYST INC (US)
  • EP2539902B1 patent drawingFigure 1
  • EP2539902B1 patent drawingFigure 2A~2B
  • EP2539902B1 patent drawingFigure 2C~2D

AI summary

The present specification discloses a system for detecting nuclear material based on at least one source of probing radiation and the radiation signatures generated from interrogating an object under inspection. In addition, the present specification describes a threshold-activation detector capable of detecting prompt neutrons, via the activation, after the source's blinding radiation has stopped. The threshold-activation detector can be manufactured from liquid fluorocarbons that allow for the detection of beta radiation and gamma rays.