# US 9,941,438 B2 · Neutron detection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,941,438 B2 - Document ID: US9941438B2 - Status: Granted - Kind: B2 - Application number: 14/521,432 - Filed: 2014-10-22 - Published: 2015-04-30 - Granted: 2018-04-10 - Earliest claimed: 2013-10-23 - Assignees: Nova Scientific, Inc. - Applicants: Nova Scientific, Inc. - Inventors: W. Bruce Feller; Paul L. White - Web page: https://patentgrep.com/patent/US9941438B2 ## CPC - H10F 30/00: Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors - G01T 3/08: with semiconductor detectors - H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION - 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 A neutron detector includes a microchannel plate having a structure that defines a plurality of microchannels, and layers of materials disposed on walls of the microchannels. The layers include a layer of neutron sensitive material, a layer of semiconducting material, and a layer of electron emissive material. For example, the layer of neutron sensitive material can include at least one of hafnium (Hf), samarium (Sm), erbium (Er), neodymium (Nd), tantalum (Ta), lutetium (Lu), europium (Eu), dysposium (Dy), or thulium (Tm). ## Claims ### Claim 1 An apparatus comprising: a microchannel plate comprising a structure that defines a plurality of microchannels; and layers of materials disposed on walls of the microchannels, the layers including a layer of neutron sensitive material, a layer of semiconducting material, and a layer of electron emissive material, in which the layer of neutron sensitive material comprises at least one of erbium (Er), neodymium (Nd), tantalum (Ta), or thulium (Tm). ### Claim 2 (depends on 1) The apparatus of claim 1 in which the layer of neutron sensitive material comprises at least 50 mol % of neutron sensitive material. ### Claim 3 (depends on 1) The apparatus of claim 1 in which the layer of neutron sensitive material comprises at least 30 mol % of neutron sensitive material. ### Claim 4 (depends on 1) The apparatus of claim 1 in which the layer of neutron sensitive material comprises at least one of boron-10, lithium-6, or gadolinium. ### Claim 5 (depends on 1) The apparatus of claim 1 in which the layer of neutron sensitive material comprises a compound that comprises at least one of boron-10, lithium-6, or gadolinium, and the compound comprises at least one of boron-10 oxide, boron-10 nitride, lithium-6 oxide, or gadolinium oxide. ### Claim 6 (depends on 1) The apparatus of claim 1 in which the structure comprises at least one of glass, polymer, or plastic. ### Claim 7 (depends on 1) The apparatus of claim 1 in which the semiconducting material comprises AlZnxOy alloy, x and y being positive integers. ### Claim 8 (depends on 1) The apparatus of claim 1 in which the electron emissive material comprises at least one of aluminum oxide (Al2O3) or magnesium oxide (MgO). ### Claim 9 (depends on 1) The apparatus of claim 1, comprising a gamma ray detector to detect gamma rays, and a coincidence unit to determine whether a signal output from the gamma ray detector indicating detection of a gamma ray occurs within a predetermined time period after a signal output from the microchannel plate indicating detection of at least one of a neutron or a gamma ray. ### Claim 10 (depends on 1) The apparatus of claim 1 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on first information derived from a first charge induced on the input electrode and/or second information derived from a second charge induced on the output electrode. ### Claim 11 (depends on 1) The apparatus of claim 1 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a first signal on the input electrode and a second signal on the output electrode. ### Claim 12 (depends on 11) The apparatus of claim 11 in which the data processor determines that a neutron has been detected when the first and second signals have different polarities. ### Claim 13 (depends on 1) The apparatus of claim 1 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a signal on the output electrode with a baseline value. ### Claim 14 (depends on 1) The apparatus of claim 1 in which the microchannel plate is capable of detecting neutrons having energy levels in a range from 0.005 eV to 1000 eV. ### Claim 15 (depends on 1) The apparatus of claim 1 in which the microchannel plate is capable of detecting neutrons having energy levels in a range from 0.025 eV to 10 eV. ### Claim 16 (depends on 1) The apparatus of claim 1 in which the microchannel plate is capable of detecting neutrons having energy levels in a range from 1 eV to 300 eV. ### Claim 17 (depends on 1) The apparatus of claim 1 in which the microchannel plate is capable of detecting neutrons having energy levels in a range from 300 eV to 1000 eV. ### Claim 18 (depends on 1) The apparatus of claim 1 in which the structure of the microchannel plate comprises neutron sensitive material that includes at least one of hafnium (Hf), tantalum (Ta), lutetium (Lu), or thulium (Tm). ### Claim 19 A method of fabricating a microchannel plate, the method comprising: fabricating a structure that defines a plurality of microchannels; and depositing a layer of neutron sensitive material, a layer of semiconducting material, and a layer of electron emissive material on walls of the microchannels, in which the layer of neutron sensitive material comprises at least one of erbium (Er), neodymium (Nd), tantalum (Ta), or thulium (Tm). ### Claim 20 (depends on 19) The apparatus of claim 19 in which the layer of neutron sensitive material comprises at least one of samarium, erbium, or neodymium, depositing a layer of neutron sensitive material comprises using atomic layer deposition to deposit a layer of neutron sensitive material, and using atomic layer deposition comprises depositing a precursor compound that includes at least one of samarium, erbium, or neodymium. ### Claim 21 (depends on 20) The method of claim 20 in which depositing the precursor compound comprises depositing at least one of Sm(N(Si(CH3)3)2)3, C27H39Sm, Er(OCC(CH3)3CHCOC(CH3)3), Er(C5H4C4H9)3, or Nd(N(Si(CH3)3)2)3. ### Claim 22 (depends on 19) The method of claim 19 in which depositing a layer of neutron sensitive material comprises using atomic layer deposition to deposit a layer of neutron sensitive material. ### Claim 23 (depends on 22) The method of claim 22 in which using atomic layer deposition to deposit a layer of neutron sensitive material comprises using atomic layer deposition to deposit at least two of boron-10, lithium-6, gadolinium, hafnium, erbium, neodymium, tantalum, lutetium, or thulium. ### Claim 24 (depends on 22) The apparatus of claim 22 in which using atomic layer deposition comprises depositing a precursor compound that includes at least one of hafnium, tantalum, lutetium, or thulium. ### Claim 25 (depends on 22) The apparatus of claim 22 in which using atomic layer deposition comprises depositing a precursor compound that includes at least one of Ta(N(CH3)2)5, Ta(OC2H5)5, (CH3)3CNTa(N(C2H5)2), or C13H33N4Ta. ### Claim 26 (depends on 19) The method of claim 19 in which depositing a layer of semiconducting material comprises using atomic layer deposition to deposit a layer of semiconducting material. ### Claim 27 (depends on 19) The method of claim 19 in which depositing a layer of electron emissive material comprises using atomic layer deposition to deposit a layer of electron emissive material. ### Claim 28 (depends on 19) The method of claim 19 in which fabricating a structure that defines a plurality of microchannels comprises fabricating a structure using a plurality of fibers each including a soluble core and a layer of cladding surrounding the soluble core, and removing the soluble core to form microchannels. ### Claim 29 (depends on 19) The method of claim 19 in which fabricating a structure that defines a plurality of microchannels comprises drawing of hollow tubes and bundling the drawn hollow tubes. ### Claim 30 (depends on 19) The method of claim 19 in which depositing a layer of neutron sensitive material, a layer of semiconducting material, and a layer of electron emissive material on walls of the microchannels comprises depositing a layer of neutron sensitive material, followed by depositing a layer of semiconducting material, and followed by depositing a layer of electron emissive material on walls of the microchannels. ### Claim 31 A method of detecting neutrons, the method comprising: using a layer of neutron sensitive material formed on a wall of a microchannel of a microchannel plate to capture a neutron and generate at least one reactant particle, the microchannel plate comprising a glass plate having a structure that defines the microchannel, the glass plate comprising glass having less than 25 mol % lead (Pb) and less than 20 mol % of the neutron sensitive material, in which the neutron sensitive material comprises at least one of erbium (Er), neodymium (Nd), tantalum (Ta), or thulium (Tm); detecting secondary electrons that are generated based on an interaction between the reactant particle and a layer of electron emissive material on the wall of the microchannel; and generating a first signal indicating detection of a neutron. ### Claim 32 (depends on 31) The method of claim 31 in which the glass plate comprises glass having less than 1 mol % lead (Pb). ### Claim 33 (depends on 31) The method of claim 31 in which the glass plate comprises glass having less than 0.1 mol % of the neutron sensitive material. ### Claim 34 (depends on 31) The method of claim 31 in which the structure of the glass plate comprises neutron sensitive material that includes at least one of hafnium (Hf), tantalum (Ta), lutetium (Lu), or thulium (Tm). ### Claim 35 An apparatus comprising: a neutron detector configured to detect neutrons having energy higher than 0.025 eV, the neutron detector including: a microchannel plate having a structure that defines a plurality of microchannels, in which the structure includes a neutron sensitive material, the neutron sensitive material including at least one of tantalum (Ta) or thulium (Tm). ### Claim 36 (depends on 35) The apparatus of claim 35 in which the neutron sensitive material comprises a compound including at least one of hafnium (Hf), tantalum (Ta), lutetium (Lu), or thulium (Tm). ### Claim 37 (depends on 35) The apparatus of claim 35 in which the neutron detector is also configured to detect neutrons having energy equal to or lower than 0.025 eV, and the neutron sensitive material comprises at least at one boron-10, lithium-6, or gadolinium. ### Claim 38 (depends on 35) The apparatus of claim 35 in which the structure comprises glass. ### Claim 39 (depends on 35) The apparatus of claim 35 in which a layer of neutron sensitive material and a layer of semiconducting material are disposed on walls of the microchannels. ### Claim 40 (depends on 39) The apparatus of claim 39 in which the semiconducting material comprises AlZnxOy alloy, x and y being positive integers. ### Claim 41 (depends on 39) The apparatus of claim 39 in which the electron emissive material comprises at least one of aluminum oxide (Al2O3) or magnesium oxide (MgO). ### Claim 42 (depends on 35) The apparatus of claim 35 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on first information derived from a first charge induced on the input electrode and second information derived from a second charge induced on the output electrode. ### Claim 43 (depends on 35) The apparatus of claim 35 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a first signal on the input electrode and a second signal on the output electrode. ### Claim 44 (depends on 43) The apparatus of claim 43 in which the data processor determines that a neutron has been detected when the first and second signals have different polarities. ### Claim 45 (depends on 35) The apparatus of claim 35 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a signal on the output electrode with a baseline value. ### Claim 46 A method of fabricating a neutron detector, the method comprising: fabricating a microchannel plate, comprising: fabricating a structure that defines a plurality of microchannels, including doping glass with a neutron sensitive material comprising at least one of tantalum (Ta), or thulium (Tm), and forming the structure using the glass doped with neutron sensitive material; and attaching an input electrode and an output electrode to the microchannel plate. ### Claim 47 (depends on 46) The method of claim 46 in which fabricating the microchannel plate comprises using atomic layer deposition to deposit a layer of semiconducting material. ### Claim 48 (depends on 46) The method of claim 46 in which fabricating the microchannel plate comprises using atomic layer deposition to deposit a layer of electron emissive material. ### Claim 49 (depends on 46) The method of claim 46 in which fabricating a structure that defines a plurality of microchannels comprises fabricating a structure using a plurality of fibers each including a soluble core and a layer of cladding surrounding the soluble core, and removing the soluble core to form microchannels. ### Claim 50 (depends on 46) The method of claim 46 in which fabricating the microchannel plate comprises depositing a layer of semiconducting material, followed by depositing a layer of electron emissive material on walls of the microchannels. ### Claim 51 A method of detecting neutrons, the method comprising: using a microchannel plate to capture a neutron and generate at least one reactant particle, the microchannel plate comprising a glass plate having a structure that defines the microchannel, the glass plate comprising glass having less than 25 mol % lead (Pb), the glass comprising a neutron sensitive material comprising at least one of tantalum (Ta) or thulium (Tm); detecting secondary electrons that are generated based on an interaction between the reactant particle and a layer of electron emissive material on the wall of the microchannel; and generating a first signal indicating detection of a neutron. ### Claim 52 (depends on 51) The method of claim 51 in which the glass plate comprises glass having less than 1 mol % lead (Pb). ### Claim 53 An apparatus comprising: a microchannel plate comprising a structure that defines a plurality of microchannels; and layers of materials disposed on walls of the microchannels, the layers including a first layer of a first neutron sensitive material, a second layer of a second neutron sensitive material, a layer of semiconducting material, and a layer of electron emissive material, in which the first neutron sensitive material is different from the second neutron sensitive material, and in which the first neutron sensitive material comprises at least one of boron, lithium, or gadolinium, and the second neutron sensitive material comprises at least one of erbium, neodymium, tantalum, lutetium, or thulium. ### Claim 54 (depends on 53) The apparatus of claim 53 in which the first neutron sensitive material is sensitive to neutrons having an energy level equal to or less than 0.025 eV, and the second neutron sensitive material is sensitive to neutrons having an energy level higher than 0.025 eV. ### Claim 55 (depends on 53) The apparatus of claim 53 in which the second layer of neutron sensitive material comprises at least 50 mol % of neutron sensitive material. ### Claim 56 (depends on 53) The apparatus of claim 53 in which the second layer of neutron sensitive material comprises at least 30 mol % of neutron sensitive material. ### Claim 57 (depends on 53) The apparatus of claim 53 in which the first layer of neutron sensitive material comprises a compound that comprises at least one of boron-10, lithium-6, or gadolinium, and the compound comprises at least one of boron-10 oxide, boron-10 nitride, lithium-6 oxide, or gadolinium oxide. ### Claim 58 (depends on 53) The apparatus of claim 53 in which the structure comprises at least one of glass, polymer, or plastic. ### Claim 59 (depends on 53) The apparatus of claim 53 in which the semiconducting material comprises AlZnxOy alloy, x and y being positive integers. ### Claim 60 (depends on 53) The apparatus of claim 53 in which the electron emissive material comprises at least one of aluminum oxide (Al2O3) or magnesium oxide (MgO). ### Claim 61 (depends on 53) The apparatus of claim 53 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on first information derived from a first charge induced on the input electrode and/or second information derived from a second charge induced on the output electrode. ### Claim 62 (depends on 53) The apparatus of claim 53 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a first signal on the input electrode and a second signal on the output electrode. ### Claim 63 (depends on 62) The apparatus of claim 62 in which the data processor determines that a neutron has been detected when the first and second signals have different polarities. ### Claim 64 (depends on 53) The apparatus of claim 53 in which the microchannel plate comprises an input electrode, an output electrode, and a glass plate comprising the microchannels, and the apparatus further comprising a data processor to determine whether a neutron has been detected based on a comparison of a signal on the output electrode with a baseline value. ### Claim 65 (depends on 53) The apparatus of claim 53 in which the microchannel plate is capable of detecting neutrons having energy levels in a range from 0.005 eV to 100 eV.