# US 8,569,710 B2 · Optimized detection of fission neutrons using boron coated straw detectors distributed in moderator material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,569,710 B2 - Document ID: US8569710B2 - Status: Granted - Kind: B2 - Application number: 12/792,521 - Filed: 2010-06-02 - Published: 2010-12-02 - Granted: 2013-10-29 - Earliest claimed: 2009-06-02 - Assignees: Proportional Technologies, Inc. - Applicants: Jeffrey L. Lacy - Inventors: Jeffrey L. Lacy - Web page: https://patentgrep.com/patent/US8569710B2 ## CPC - G01T 3/008: {using an ionisation chamber filled with a gas, liquid or solid, e.g. frozen liquid, dielectric (G01T3/006 takes precedence)} - G01V 5/26: Passive interrogation, i.e. by measuring radiation emitted by objects or goods - 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) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract The present invention includes an apparatus and method for neutron radiation detection. The apparatus comprises combining thin walled, boron-coated straw tubes with a plastic moderator material interspersed around the tubes. The method involves using such an apparatus through application of voltage to a central wire running inside the tubes and collecting electrical pulses generated thereby. ## Claims ### Claim 1 A portal monitoring system for detecting neutrons emitted from cargo comprising: a plurality of thin wall boron coated straw detectors, and a moderator material, other than materials making up said straw detectors, interspersed between said straw detectors, wherein the interspersed moderator material comprises plastic tubes having an internal diameter 50 to 500 μm larger than the outer diameter of the straw detectors. ### Claim 2 (depends on 1) The system of claim 1, wherein said tubes have a variable wall thickness to achieve a constant straw detector density. ### Claim 3 (depends on 1) The system of claim 1, wherein said tubes have a variable wall thickness to achieve a variable straw detector density. ### Claim 4 (depends on 1) The device system of claim 1, wherein said moderator material comprises polyethylene. ### Claim 5 A device for detection of energetic neutrons comprising a block of high density polyethylene or other plastic having a hydrogen content and having holes passing through the length of the block arranged in a regular array with constant hole center to center distance and having inserted in said holes boron coated straw detectors comprising a thin wall tube having a thin inner wall coating of thickness in the range of 0.5 μm to 2.0 μm and high in 10B content of at least 60% by weight and having a thin electrically conductive wire centered and tensioned in the middle of said tube and suitable high voltage electrical insulation at the ends; high positive voltage source connected to the central wire, and a collector for the electrical pulses from one end of the wire. ### Claim 6 (depends on 5) The device of claim 5, wherein said moderator material is HDPE. ### Claim 7 (depends on 5) The device of claim 5, wherein said straw detectors being spaced apart from between 5 mm to about 23 mm. ### Claim 8 (depends on 5) The device of claim 5, comprising between 50 to 1200 individual straw detectors. ### Claim 9 (depends on 5) The device of claim 5, comprising between 50 to 800 straw detectors. ### Claim 10 (depends on 5) The device of claim 5, comprising between 50 to 200 straw detectors. ### Claim 11 (depends on 5) The device of claim 5, wherein said straw detectors are 200 cm in length and 4 mm in diameter. ### Claim 12 (depends on 5) The device of claim 5, wherein said device has a sensitivity of at least about 3.3 cps/ng. ### Claim 13 (depends on 5) The device of claim 5, wherein said straw detectors have a diameter between 4mm and 25 mm. ### Claim 14 (depends on 5) The device of claim 5, wherein said moderator material interspersed between neighboring straw detectors comprises a thickness of between 9 and 12 mm. ### Claim 15 (depends on 5) The device of claim 5, wherein the other plastic comprises polyethylene. ### Claim 16 A portal monitoring system for detecting neutrons emitted from cargo comprising: a plurality of thin wall boron coated straw detectors, and a moderator material, other than materials making up said straw detectors, interspersed between said straw detectors, wherein said moderator material interspersed between said straw detectors comprises a solid block of HDPE with holes passing through to accommodate said straw detectors. ### Claim 17 (depends on 16) The system of claim 16, wherein said straw detectors are uniformly distributed within said moderator material. ### Claim 18 (depends on 16) The system of claim 16, wherein said straw detectors are non-uniformly distributed within said moderator material. ### Claim 19 (depends on 16) The system of claim 16, wherein said detector detects both neutrons and gamma emissions. ### Claim 20 (depends on 16) The system of claim 16, wherein said straw detectors are arranged to be more concentrated near a forward portion of the moderator material. ### Claim 21 A portal monitoring system for detecting neutrons emitted from cargo comprising: a plurality of thin wall boron coated straw detectors, and a moderator material, other than materials making up said straw detectors, interspersed between said straw detectors, wherein said moderator material is interspersed between said detectors by inserting at least one straw detector within a plastic tube having a larger internal diameter than the external diameter of said straw detectors, and arranging a plurality of plastic tubes in a packed arrangement, each combination of plastic tube and straw detector(s) acting as an independent module. ### Claim 22 (depends on 21) The device system of claim 21, wherein said moderator material comprises polyethylene.