# US 7,333,701 B1 · Neutron detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,333,701 B1 - Document ID: US7333701B1 - Status: Granted - Kind: B1 - Application number: 11/522,855 - Filed: 2006-09-18 - Granted: 2008-02-19 - Earliest claimed: 2006-09-18 - Assignees: Nova Scientific, Inc. - Inventors: W. Bruce Feller; Paul L. White; P. Brian White; R. Gregory Downing - Web page: https://patentgrep.com/patent/US7333701B1 ## CPC - G01T 3/00: Measuring neutron radiation (G01T5/00 takes precedence) - 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 An apparatus including a microchannel plate having a structure that defines multiple microchannels. The structure includes multiple claddings that form the walls of the microchannels, each of the claddings including a semiconducting layer. The claddings are surrounded by a glass having a lower percentage of materials having atomic numbers higher than 34 as compared to the cladding. The glass has a higher percentage of neutron absorbing material than the cladding, the neutron absorbing material capable of capturing neutrons in reactions that result in secondary electron emissions in the microchannels. ## Claims ### Claim 1 A method comprising: fabricating a channel plate using a plurality of fibers each including a soluble core, a first layer of glass cladding surrounding the soluble core, and a second layer of glass cladding surrounding the first layer of glass cladding, the first layer of glass cladding containing a higher percentage of lead than the second layer of glass cladding, the second layer of cladding containing a higher percentage of at least one of boron-10, lithium-6, and gadolinium than the first layer of glass cladding; and removing the soluble core to form channels. ### Claim 2 (depends on 1) The method of claim 1, wherein the second layer of glass cladding has less than 1 mol % of lead. ### Claim 3 (depends on 1) The method of claim 1, wherein fabricating the channel plate comprises drawing the fibers to reduce the cross sectional areas of the fibers. ### Claim 4 (depends on 1) The method of claim 1, wherein each of at least some of the channels has a diameter less than 150 microns. ### Claim 5 (depends on 1) The method of claim 1, further comprising exposing the first layer of glass cladding to hydrogen at a high temperature. ### Claim 6 A method comprising: fabricating a microchannel plate using a plurality of fibers each including a soluble core, a first layer of cladding surrounding the soluble core, and a second layer of cladding surrounding the first layer of cladding, the first layer of cladding having a higher percentage of material having atomic numbers greater than 34 as compared to the second layer of cladding, the second layer of cladding having a higher percentage of neutron absorbing material than the first layer of cladding; and removing the soluble core to form microchannels. ### Claim 7 (depends on 6) The method of claim 6, wherein fabricating the channel plate comprises drawing the fibers to reduce the cross sectional areas of the fibers. ### Claim 8 (depends on 6) The method of claim 6, wherein each of at least some of the channels has a diameter less than 150 microns. ### Claim 9 (depends on 6) The method of claim 6, wherein the second layer of cladding comprises glass having less than 1 mol % of lead. ### Claim 10 (depends on 6) The method of claim 6, wherein the neutron absorbing material comprises at least one of boron-10, lithium-6, and gadolinium. ### Claim 11 A method comprising: applying a bias voltage to a microchannel plate comprising a structure that defines a plurality of microchannels, the structure including a plurality of claddings that form the walls of the microchannels, the claddings having a semiconducting layer, the claddings being surrounded by a glass having a lower percentage of lead than the claddings, the glass having a higher percentage of neutron absorbing material than the cladding; capturing neutrons in the glass and generating secondary electron emissions in the microchannels; and detecting the secondary electron emissions. ### Claim 12 (depends on 11) The method of claim 11, wherein the neutron absorbing material comprises at least one of boron-10, lithium-6, and gadolinium. ### Claim 13 (depends on 11) The method of claim 11, further comprising generating an image of an object based on detection of neutrons by the microchannel plate. ### Claim 14 (depends on 11) The method of claim 11, further comprising detecting a nuclear material based on detection of neutrons by the microchannel plate. ### Claim 15 A method comprising: laminating layers of fibers, each fiber including a core surrounded by a cladding, the cladding having a higher percentage of at least one of boron-10, lithium-6, and gadolinium than the core; coating a first conducting layer on a first surface of the laminated layers of fiber; and coating a second conducting layer on a second surface of the laminated layers of fiber. ### Claim 16 (depends on 15) The method of claim 15, wherein the core of at least some of the fibers has less than 0.1 mol % of boron-10, lithium-6, and gadolinium. ### Claim 17 (depends on 15) The method of claim 15, wherein laminating layers of fibers comprises orienting a first layer of fibers substantially parallel to a first direction and orienting a second layer of fibers substantially parallel to a second direction, the first direction being at an angle to the second direction. ### Claim 18 A method comprising: applying a bias voltage to a laminate comprising layers of fibers, each fiber including a core surrounded by a cladding, the cladding having a higher percentage of at least one of boron-10, lithium-6, and gadolinium as compared to the core; capturing neutrons using the boron-10, lithium-6, or gadolinium in the cladding and generating secondary electron emissions; and detecting the secondary electron emissions. ### Claim 19 An apparatus comprising: a microchannel plate comprising a structure that defines a plurality of microchannels, the structure including a plurality of claddings that form the walls of the microchannels, each of the claddings comprising a semiconducting layer, the claddings being surrounded by a glass, the glass having a lower percentage of material having atomic numbers higher than 34 as compared to the claddings, the glass having a higher percentage of neutron absorbing material than the cladding, the neutron absorbing material capable of capturing neutrons in reactions that result in secondary electron emissions in the microchannels. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein the claddings comprise at least 10 mol % of lead. ### Claim 21 (depends on 19) The apparatus of claim 19, wherein each of at least some of the microchannels has a diameter less than 150 microns. ### Claim 22 (depends on 19) The apparatus of claim 19, wherein each of at least some of the microchannels has a length that is at least 10 times the diameter of the microchannel. ### Claim 23 (depends on 19) The apparatus of claim 19, wherein each of at least some of the microchannels has at least one of a circular, a square, a rectangular, and a hexagonal cross section. ### Claim 24 (depends on 19) The apparatus of claim 19, further comprising a shield to reduce the amount of gamma rays reaching the microchannel plate. ### Claim 25 (depends on 19) The apparatus of claim 19, further comprising an image sensor to detect the secondary electron emissions. ### Claim 26 (depends on 19) The apparatus of claim 19, further comprising a counter to count the number of detected neutrons. ### Claim 27 An apparatus comprising: a microchannel plate comprising a structure that defines a plurality of microchannels, the structure including inner claddings each forming the wall of one of the microchannels, each inner cladding being surrounded by an outer cladding comprising a lower percentage of lead than the inner cladding, the outer cladding having a higher percentage of at least one of boron-10, lithium-6, and gadolinium than the inner cladding. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the inner cladding comprise at least 10 mol % of lead. ### Claim 29 (depends on 27) The apparatus of claim 27, wherein the outer cladding comprise at least 1 mol % of at least one of boron-10, lithium-6, and gadolinium. ### Claim 30 (depends on 27) The apparatus of claim 27, wherein some of the outer claddings associated with different microchannels are fused together into a continuous piece of material. ### Claim 31 An apparatus comprising: a laminate comprising layers of fibers, each fiber including a core surrounded by a cladding, the cladding having a higher percentage of at least one of boron-10, lithium-6, and gadolinium as compared to the core; a first conducting layer coated on a first surface of the laminate; and a second conducting layer coated on a second surface of the laminate. ### Claim 32 (depends on 31) The apparatus of claim 31, wherein the core of each of at least some of the fibers comprises a glass that has less than 0.1 mol % of boron-10, lithium-6, and gadolinium. ### Claim 33 (depends on 31) The apparatus of claim 31, wherein the cladding of each of at least some of the fibers comprises a glass that has more than 1 mol % of at least one of boron-10, lithium-6, and gadolinium. ### Claim 34 (depends on 31) The apparatus of claim 31, wherein the cladding in each of at least some of the fibers has a thickness in a range between 1 to 10 microns. ### Claim 35 (depends on 31) The apparatus of claim 31, wherein the cladding in each of at least some of the fibers has a thickness in a range between 2 to 5 microns. ### Claim 36 (depends on 31) The apparatus of claim 31, wherein the laminate comprises a first layer of fibers that are parallel to a first direction and a second layer of fibers that are parallel to a second direction, the first direction being at an angle to the second direction. ### Claim 37 (depends on 31) The apparatus of claim 31, wherein in each layer of fiber, the fibers are spaced apart by distances in a range between 100 to 300 microns.