Abstract: Systems and methods for detecting neutrons. One or more neutron-sensitive scintillators can be configured from a plurality of nano-sized particles, dopants and an extruded plastic material, such as polystyrene. The nano-sized particles can be compounded into the extruded plastic material with at least one dopant that permits the plastic material to scintillate. One or more plastic light collectors can be associated with a neutron-sensitive scintillator, such that the plastic light collector includes a central hole thereof. A wavelength-shifting fiber can then be located within the hole. The wavelength shifting (WLS) fiber absorbs scintillation light having a wavelength thereof and re-emits the light at a longer wavelength.

Abstract: A neutron detector is provided which is able to measure thermal neutron radiation within a gap filled with a substance that permits scintillation in the absorption of thermal neutron radiation, the gap being formed between at least a first and second spaced apart photodetector working in electrical coincidence. The substance disposed within the gap can be either a gas, liquid or solid. In the case of a gas, a shell is used so that the gas can be retained and kept under pressure. The neutron detector is able to differentiate between gamma radiation and neutron energy. An alternate embodiment of the novel detector includes a device which employs a plurality of detectors surrounding a moderator which can be used to measure both thermal and high energy neutrons.

Abstract: A method of fabricating an apparatus for an enhanced imaging sensor consisting of pixellated micro columnar scintillation film material for x-ray imaging comprising a scintillation substrate and a micro columnar scintillation film material in contact with the scintillation substrate. The micro columnar scintillation film material is formed from a doped scintillator material. According to the invention, the micro columnar scintillation film material is subdivided into arrays of optically independent pixels having interpixel gaps between the optically independent pixels. These optically independent pixels channel detectable light to a detector element thereby reducing optical crosstalk between the pixels providing for an X-ray converter capable of increasing efficiency without the associated loss of spatial resolution. The interpixel gaps are further filled with a dielectric and or reflective material to substantially reduce optical crosstalk and enhance light collection efficiency.

Abstract: The invention provides an improved neutron detector of fast neutrons and may be used particularly in the advanced detection technologies for the non-intrusive interrogation of passengers luggage, large cargo and trucks.

Abstract: A 6Li doped glass scintillator sheet with grooves cut at given spacings in horizontal and vertical directions. Bundles of wavelength shifting fibers placed in the vertical grooves and fluorescence reflector buried in the horizontal grooves make a group of detection pixels. Neutron detecting media are provided on the top surface and bundles of wavelength shifting fibers are arranged horizontally on the bottom surface of the scintillator. Fluorescence generated by stimulation with the neutrons entering the detection pixels and with the neutrons incident on the neutron detecting media are detected by the wavelength shifting fibers. The detected fluorescence is converted to electric signals with a multi-channel photomultiplier tube, with pulse signals for simultaneous counting generated from a retriggerable, constant time-duration pulse generator and recorded as time-series data by parallel interfaces. The recorded data are analyzed by the simultaneous counting method to produce a two-dimensional neutron image.

Abstract: Systems and methods for detecting neutrons are disclosed. One or more neutron-sensitive scintillators can be configured from a plurality of nano-sized particles and a plastic material, such as polystyrene. The nano-sized particles can be compounded into the plastic material with at least one dopant that permits the plastic material to scintillate. One or more plastic light collectors can be associated with a neutron-sensitive scintillator, such that the plastic light collector includes a central hole thereof. A wavelength-shifting fiber can then be located within the hole. The wavelength shifting (WLS) fiber absorbs scintillation light having a wavelength thereof and remits the light at a longer wavelength.

Abstract: A system for detecting neutron radiation. A liquid cocktail mixture comprised of a neutron absorber and a scintillator is housed in a Teflon® tube having a mirror at one end of the tube and a windowed portal at the other end of the tube. Neutrons that penetrate the tube react with the neutron absorber producing ionization that excites a scintillator to produce photons. A photo-multiplier tube is coupled with the windowed portal for receiving photons and converting the photons to electrical signals. A processing device is coupled to the photo-multiplier output for receiving and analyzing the electrical signals so as to provide a measurement pertaining to the presence and relative strength of neutron radiation. The tube can be adapted to function as a portable survey instrument. Alternatively, the tube can be stretched to cover large apertured areas.

Abstract: A non-destructive method for quantifying the hydrogen content or a hydrogen-bearing constituent in a material is based on the principle of moderating neutron spectroscopy. This technique is particularly suited for analyzing materials containing the high scattering/capture cross-section element of hydrogen. The method involves exposing a neutron moderator to a beam of radiation comprising neutrons and measuring thermal neutron intensities at a plurality of locations in the moderator. These measured intensities reflect the energy distribution of the beam of radiation incident upon the moderator. Thus, by measuring these intensities with the material present, and comparing these intensities to a model, to those of a composition standard(s), or combinations thereof, the hydrogen content of the material is quantified. Furthermore, the hydrogen-bearing constituent of the material is quantified by knowing or estimating the chemical or molecular structure of the material.

Abstract: An improved fast neutron detector fabricated with alternating layers of hydrogenous, optically transparent, non scintillating material and scintillating material. Fast neutrons interact with the hydrogenous material generating recoil protons. The recoil protons enter the scintillating material resulting in scintillations. The detector is optically coupled to a photomultiplier tube which generates electrical pulses proportional in amplitude to the intensity of the scintillations, and therefore are an indication of the energy of the fast neutrons impinging upon the detector. Alternating layers of materials are dimensioned to optimize total efficiency of the detector, or to optimize the spectroscopy efficiency of the detector. The scintillating material is preferably ZnS, and the hydrogenous material is preferably plastic. The detector is ideally suited for well logging applications and fast neutron monitor applications.

Abstract: A method of monitoring a nuclear reactor includes monitoring the nuclear reactor with a plurality of radiation sensors having spaced apart attachments to a radiation hard cable; providing signal processing equipment at each end of the cable for processing signals from the radiation sensors; establishing signal time intervals based upon differences in time of arrival of signals from the radiation sensors to the signal processing equipment at each end of the cable; producing a plurality of output signals each of which has an amplitude proportional to a difference in time of arrival of a signal to the signal processing equipment at each end of the cable; and rejecting output signals which have a difference in time of arrival outside of the signal time intervals.

Abstract: A neutron detector composed of a matrix of scintillating particles imbedded in a lithiated glass is disclosed. The neutron detector detects the neutrons by absorbing the neutron in the lithium-6 isotope which has been enriched from the natural isotopic ratio to a commercial ninety five percent. The utility of the detector is optimized by suitably selecting scintillating particle sizes in the range of the alpha and the triton. Nominal particle sizes are in the range of five to twenty five microns depending upon the specific scintillating particle selected.

Abstract: A non-destructive method for quantifying the hydrogen content or a hydrogen-bearing constituent in a material is disclosed. The method is based on the principle of moderating neutron spectroscopy which is particularly suited for analyzing materials containing the high scattering/capture cross-section element of hydrogen. The method comprises the steps of exposing a neutron moderator to a beam of radiation comprising neutrons and measuring thermal neutron intensities at a plurality of locations in the moderator. These measured intensities reflect the energy distribution of the beam of radiation incident upon the moderator. Thus, by measuring these intensities with the material present, and comparing these intensities to a model, to those of a composition standard(s), or combinations thereof, the hydrogen content of the material is quantified. Furthermore, the hydrogen-bearing constituent of the material is quantified by knowing or estimating the chemical or molecular structure of the material.

Abstract: A neutron detecting scintillator that has a very short decay time, that can capture neutrons in high efficiency and that is composed of light elements comprises the Li2B4O7 single crystal or the 6Li and 11B or 10B enriched 6Li211B4O7 or 6Li210B4O7 single crystal, in which 6Li and 11B or 10B have large neutron capture cross sections and fluorescence that is emitted from an ionizing radiation generated through their neutron capture reaction has a short-lived component not longer than 10 ns.

Abstract: A non-destructive method for quantifying the hydrogen content or a hydrogen-bearing constituent in a material. Moderating neutron spectroscopy is particularly suited for analyzing materials containing the high scattering/capture cross-section element of hydrogen. A neutron moderator is exposed to a beam of neutron radiation and the thermal neutron intensities at a number of locations in the moderator are then measured. The measured intensities reflect the energy distribution of the radiation beam incident upon the moderator. By measuring intensities with the material present and comparing the intensities to a model, or to those of a composition standard(s), the hydrogen content of the material is quantified. The hydrogen-bearing constituent of the material may be further quantified by knowing or estimating the chemical or molecular structure of the material.

Abstract: An improved fast neutron detector fabricated with alternating layers of hydrogenous, optically transparent, non scintillating material and scintillating material. Fast neutrons interact with the hydrogenous material generating recoil protons. The recoil protons enter the scintillating material resulting in scintillations. The detector is optically coupled to a photomultiplier tube which generates electrical pulses proportional in amplitude to the intensity of the scintillations, and therefore are an indication of the energy of the fast neutrons impinging upon the detector. Alternating layers of materials are dimensioned to optimize total efficiency of the detector, or to optimize the spectroscopy efficiency of the detector. The scintillating material is preferably ZnS, and the hydrogenous material is preferably plastic. The detector is ideally suited for well logging applications and fast neutron monitor applications.

Abstract: To provide a neutron scintillator, which does not contain a heavy element, which is absolutely necessary in realizing a scintillation detector having low sensitivity to gamma ray and fully capable of counting high intensity neutron, Cu is doped in oxide comprised of Li and B. The oxide comprised of Li and B is a transparent single crystal having composition ratio of Li2B4O7. The neutron scintillator contains Cu by 0.001 to 0.1 wt %. Furthermore, a (001) plane cut off perpendicularly to a growth axis and polished from the single crystal whose orientation has been grown in a <001> axis is made to be a scintillator plate crystal.

Abstract: A neutron rem meter utilizing proton recoil and thermal neutron scintillators to provide neutron detection and dose measurement. In using both fast scintillators and a thermal neutron scintillator the meter provides a wide range of sensitivity, uniform directional response, and uniform dose response. The scintillators output light to a photomultiplier tube that produces an electrical signal to an external neutron counter.

Abstract: An improved fast neutron detector fabricated with alternating layers of hydrogenous, optically transparent, non scintillating material and scintillating material. Fast neutrons interact with the hydrogenous material generating recoil protons. The recoil protons enter the scintillating material resulting in scintillations. The detector is optically coupled to a photomultiplier tube which generates electrical pulses proportional in amplitude to the intensity of the scintillations, and therefore are an indication of the energy of the fast neutrons impinging upon the detector. Alternating layers of materials are dimensioned to optimize total efficiency of the detector, or to optimize the spectroscopy efficiency of the detector. The scintillating material is preferably ZnS, and the hydrogenous material is preferably plastic. The detector is ideally suited for well logging applications and fast neutron monitor applications.

Abstract: Radiation doses ranging from a very weak level to a very high instantaneous level can be monitored real-time by, a differential and integral type of radiation measuring apparatus in a convenient and precise manner using a stimulable phosphor as a radiation detecting medium. The radiation detecting portion comprises in planar superposition a bundle of laterally radiating optical fibers, a stimulable phosphor, an optical filter centered at the wavelength of fluorescence, and a-bundle of wavelength shifting optical fibers sensitive to the wavelength of stimulated fluorescence. On the basis of two actions of the stimulable phosphor, one for emitting stimulated fluorescence in proportion to the dose of incident radiation upon illumination with exciting light and the other for emitting prompt fluorescence upon excitation by the incident radiation, the radiation detecting portion selectively detects stimulated fluorescence and prompt fluorescence at specified time intervals.

Abstract: Simultaneous measurement of neutron flux and temperature is provided by a single sensor which includes a phosphor mixture having two principal constituents. The first constituent is a neutron sensitive Li6F and the second is a rare-earth activated Y2O3 thermophosphor. The mixture is coated on the end of a fiber optic, while the opposite end of the fiber optic is coupled to a light detector. The detected light scintillations are quantified for neutron flux determination, and the decay is measured for temperature determination.

Abstract: An improved fast neutron detector fabricated with alternating layers of hydrogenous, optically transparent, non scintillating material and scintillating material. Fast neutrons interact with the hydrogenous material generating recoil protons. The recoil protons enter the scintillating material resulting in scintillations. The detector is optically coupled to a photomultiplier tube which generates electrical pulses proportional in amplitude to the intensity of the scintillations, and therefore are an indication of the energy of the fast neutrons impinging upon the detector. Alternating layers of materials are dimensioned to optimize total efficiency of the detector, or to optimize the spectroscopy efficiency of the detector. The scintillating material is preferably ZnS, and the hydrogenous material is preferably plastic. The detector is ideally suited for well logging applications and fast neutron monitor applications.

Abstract: An improved fast neutron detector fabricated with alternating layers of hydrogenous, optically transparent, non scintillating material and scintillating material. Fast neutrons interact with the hydrogenous material generating recoil protons. The recoil protons enter the scintillating material resulting in scintillations. The detector is optically coupled to a photomultiplier tube which generates electrical pulses proportional in amplitude to the intensity of the scintillations, and therefore are an indication of the energy of the fast neutrons impinging upon the detector. Alternating layers of materials are dimensioned to optimize total efficiency of the detector, or to optimize the spectroscopy efficiency of the detector. The scintillating material is preferably ZnS, and the hydrogenous material is preferably plastic. The detector is ideally suited for well logging applications and fast neutron monitor applications.

Abstract: A system for improving the resolution of nuclear medicine gamma cameras. A pixellated crystal scintillator is optically connected to position sensitive photomultiplier tubes. Photons incident on the crystal scintillator travel a distance through the crystal that is directly proportional to the energy level of the photon before converting to photoelectrons. The system uses this depth of interaction information to classify the received photons according to their energy levels. Images may then be displayed using information from only those photons that are within the selected energy class.

Abstract: A 6Li doped glass scintillator sheet is provided with grooves that are cut at given spacings in both a horizontal and a vertical direction. Bundles of wavelength shifting fibers are placed in the vertical grooves and a fluorescence reflector Al2O3 is buried in the horizontal grooves to make a group of detection pixels as separated by the horizontal and vertical grooves. Neutron detecting mediums which are each a mixture of YAlO3:Ce in powder form with a neutron converter 6LiF are provided on the top surface of the scintillator. Bundles of wavelength shifting fibers are also arranged horizontally on the bottom surface of the scintillator.

Abstract: Crystals of lithium tetraborate or alpha-barium borate had been found to be neutron detecting materials. The crystals are prepared using known crystal growing techniques, wherein the process does not include the common practice of using a fluxing agent, such as sodium oxide or sodium fluoride, to reduce the melting temperature of the crystalline compound. Crystals prepared by this method can be sliced into thin single or polycrystalline wafers, or ground to a powder and prepared as a sintered compact or a print paste, and then configured with appropriate electronic hardware, in order to function as neutron detectors.

Abstract: A thermal neutron detector comprises an inorganic scintillation crystal, an inner sleeve on said scintillation crystal and including boron-10, and an outer lead sleeve on said inner sleeve for shielding gamma rays from the inner layer. The boron-10 may be carried in a resiliently compressible silicone cast on the crystal to form a sleeve which functions to mechanically support the crystal inside a detector casing. The resiliently compressible, thermal neutron absorbing layer may also be used in other applications as a thermal neutron shield.

Abstract: In one aspect, the invention encompasses a method of detecting radioactive decay, comprising: a) providing a sample comprising a radioactive material, the radioactive material generating decay particles; b)providing a plurality of detectors proximate the sample, the detectors comprising a first set and a second set, the first set of the detectors comprising liquid state detectors utilizing liquid scintillation material coupled with photo tubes to generate a first electrical signal in response to decay particles stimulating the liquid scintillation material, the second set of the detectors comprising solid state detectors utilizing a crystalline solid to generate a second electrical signal in response to decay particles stimulating the crystalline solid; c) stimulating at least one of the detectors to generate at least one of the first and second electrical signals, the at least one of the first and second electrical signals being indicative of radioactive decay in the sample.

Abstract: An imaging ionizing radiation detector with a high pixel resolution is described. The detector comprises a scintillating crystal and associated sensors which determine the energy and position of the scintillation with high spatial, temporal, and energy resolution. The position sensing is done with a photon counting and position sensitive detector. The detector can achieve sub-millimeter resolution and the position determination is performed at MHZ rates.