# US 2014/0197321 A1 · Composite gamma-neutron detection system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197321 A1 - Document ID: US20140197321A1 - Status: Published application - Kind: A1 - Application number: 13/740,075 - Filed: 2013-01-11 - Published: 2014-07-17 - Earliest claimed: 2013-01-11 - Inventors: Joseph Bendahan; Edward James Morton - Web page: https://patentgrep.com/patent/US20140197321A1 ## CPC - G01T 1/20: with scintillation detectors - G01T 1/2008: {using a combination of different types of scintillation detectors, e.g. phoswich} - G01T 3/06: with scintillation detectors - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) ## Abstract The present invention provides a gamma-neutron detector based on mixtures of thermal neutron absorbers that produce heavy-particle emission following thermal capture. The detector consists of one or more thin screens embedded in transparent hydrogenous light guides, which also serve as a neutron moderator. The emitted particles interact with the scintillator screen and produce a high light output, which is collected by the light guides into a photomultiplier tube and produces a signal from which the neutrons are counted. Simultaneous gamma-ray detection is provided by replacing the light guide material with a plastic scintillator. The plastic scintillator serves as the gamma-ray detector, moderator and light guide. The neutrons and gamma-ray events are separated employing Pulse-Shape Discrimination (PSD). The detector can be used in several scanning configurations including portal, drive-through, drive-by, handheld and backpack, etc. ## Claims ### Claim 1 A system for detection of neutrons and gamma rays, comprising: at least one light guide, a scintillator screen embedded into the light guide, wherein the scintillator screen comprises a thermal neutron absorber material, said material interacting with neutrons to emit heavy particles, and said heavy particles interacting with the scintillator screen to produce light, a first photodetector which receives the produced light through said light guide, and converts the light to a measurable signal, a plastic scintillator producing light on interaction with gamma-rays, a barrier placed along a length of said plastic scintillator and along a length of said scintillator screen to prevent cross-contamination between optical signals from the neutron and gamma detection materials, a second photodetector which collects the produced light from said plastic scintillator, and converts the light to a measurable signal, and a first counter and a second counter for counting pulses generated by the first photodetector and the second photodetector, respectively. ### Claim 2 (depends on 1) The system of claim 1 wherein the second counter is a Multi-Channel Analyzer (MCA) that is used to measure the spectra of the gamma rays. ### Claim 3 (depends on 1) The system of claim 1, wherein the thermal neutron absorber material comprise 6Li or 10B. ### Claim 4 (depends on 1) The system of claim 1, wherein said plastic scintillator comprises of polyvinyl toluene (PVT). ### Claim 5 (depends on 1) The system of claim 1 further comprising a Pulse-Shape Discrimination (PSD) circuit that separates the neutron and gamma-ray events measured by the first photodetector. ### Claim 6 A system for detection of neutrons and gamma rays, comprising: a screen comprising a thermal neutron absorber material, said material interacting with neutrons to emit heavy particles; a plastic scintillator into which said screen is embedded, said plastic scintillator producing light on interaction with said heavy particles; at least one photodetector which collects the produced light and converts the light to a measurable signal, and a Pulse-Shape Discrimination (PSD) circuit that separates the neutron and gamma-ray events measured by the at least one photodetector. ### Claim 7 (depends on 6) The system of claim 6, wherein the scintillator material is silver activated zinc sulfide (ZnS(Ag)) phosphorous. ### Claim 8 (depends on 6) The system of claim 6, wherein the thermal neutron absorber material comprise 6Li or 10B. ### Claim 9 (depends on 6) The system of claim 6 further comprising at least one counter for counting pulses generated by the at least one photodetector. ### Claim 10 (depends on 6) The system of claim 6, wherein said plastic scintillator is fabricated from polyvinyl toluene (PVT). ### Claim 11 A gamma-neutron detector, comprising: a first gamma-sensitive scintillation panel; a second gamma-sensitive scintillation panel; and a neutron detector, wherein said neutron detector is positioned between the first gamma-sensitive scintillation panel and the second gamma-sensitive scintillation panel. ### Claim 12 (depends on 11) The gamma-neutron detector of claim 11 wherein the neutron detector comprises a neutron sensitive composite scintillator. ### Claim 13 (depends on 12) The gamma-neutron detector of claim 12 wherein the neutron sensitive composite scintillator comprises a mixture of neutron sensitive material and ZnS. ### Claim 14 (depends on 13) The gamma-neutron detector of claim 13 wherein the neutron sensitive material comprises 6Li or 10B. ### Claim 15 (depends on 13) The gamma-neutron detector of claim 13 wherein the neutron sensitive material has a density of up to 30% by volume of the neutron sensitive composite scintillator. ### Claim 16 (depends on 11) The gamma-neutron detector of claim 11 further comprising a glass layer placed between the neutron detector and at least one of the first or second gamma-sensitive scintillation panels. ### Claim 17 (depends on 11) The gamma-neutron detector of claim 11 wherein the gamma-sensitive scintillation panel comprises at least one of an organic solid scintillator, an inorganic solid scintillator, or a liquid scintillator positioned between glass layers. ### Claim 18 (depends on 11) The gamma-neutron detector of claim 11 wherein the first and second gamma-sensitive scintillation panels and neutron detector are adapted to generate optical signals and wherein the gamma-neutron detector further comprises at least one photodetector to detect said optical signals. ### Claim 19 (depends on 11) The gamma-neutron detector of claim 11 wherein at least one of the first or second gamma-sensitive scintillation panels are thicker than the neutron detector. ### Claim 20 (depends on 11) The gamma-neutron detector of claim 11 wherein the first and second gamma-sensitive scintillation panels have a faster decay time than the neutron detector. ### Claim 21 (depends on 18) The gamma-neutron detector of claim 18 wherein pulse shapes of the generated optical signals are analyzed to discriminate between gamma interactions and neutron interactions. ### Claim 22 (depends on 11) The gamma-neutron detector of claim 11 further comprising at least two gamma sensitive scintillation panels and at least one neutron detector. ### Claim 23 (depends on 22) The gamma-neutron detector of claim 22 wherein the at least two gamma sensitive scintillation panels and at least one neutron detector are angled relative to the direction of incoming radiation. ### Claim 24 (depends on 11) A portal gantry detection system having a top, right, and left side wherein said top, left, and right sides each comprise the gamma-neutron detector of claim 11. ### Claim 25 (depends on 11) A mobile detection system comprising a boom wherein said boom comprises the gamma-neutron detector of claim 11. ### Claim 26 A system for detection of neutrons and gamma rays, comprising: a plurality of scintillator screens comprising thermal neutron absorber materials, said materials interacting with neutrons to emit heavy particles, and said heavy particles interacting with scintillator screens to produce light, a plurality of light guides into which said scintillator screens are embedded, said light guides serving as a neutron moderating medium, a first photodetector which receives the produced light through said light guides, and converts the light to a measurable signal, a plastic scintillator producing light on interaction with gamma-rays, a reflector placed between said plastic scintillator and said scintillator screens to prevent cross-contamination between optical signals from the neutron and gamma detection materials, and a second photodetector which collects the produced light from said plastic scintillator, and converts the light to a measurable signal. ### Claim 27 (depends on 26) The system of claim 26 further comprising a first counter and a second counter for counting the pulses generated by the first photodetector and the second photodetector, respectively.