87 results about "Neutron emission" patented technology

Described herein are integrated systems for generating neutrons to perform a variety of tasks including: on-line analysis of bulk material and industrial process control (as shown in FIG. 1), security interrogation (as shown in FIG. 2), soil and environmental analysis, and medical diagnostic treatment. These systems are based on novel gas-target neutron generation which embodies the beneficial characteristics of replenishable fusible gas targets for very long lifetime, stability and continuous operation, combined with the advantageous features common to conventional accelerator neutron tubes including: on / off operation, hermetically sealed operation, and safe storage and transport. Innovative electron management techniques provide gas-target neutron production efficiencies that are comparable or surpass existing sources. The high-pressure high-resistance gaseous discharge is presented as a favorable gas-target neutron generator embodiment, combining ion source regions, accelerator regions, gas-target regions and electron management components within a single simple cost-effective device that is adaptable to various geometric configurations that provide specific neutron emission profiles for greater analysis capacity.

The presence of radiation shielding material concealing illegitimate content in a container is detected by obtaining each of measured gamma-ray data and measured neutron data from the container, and comparing the measured gamma-ray and neutron data to expected gamma-ray and neutron data. An anomaly between the measured data and the expected data is an indicum of the presence of such material shielding such illegitimate content.

An apparatus for selective radiation detection includes a neutron detector that facilitates detection of neutron emitters, e.g. plutonium, and the like; a gamma ray detector that facilitates detection of gamma ray sources, e.g., uranium, and the like. The apparatus comprises a first light guide, optically coupled to a first optical detector; a second light guide, optically coupled to a second optical detector a sheet of neutron scintillator, opaque for incoming optical photons, said sheet of neutron scintillator sandwiched between the first and the second light guides. The second light guide comprises a gamma ray scintillator material.

An apparatus for selective radiation detection includes a neutron detector that facilitates detection of neutron emitters, e.g. plutonium, and the like; a gamma ray detector that facilitates detection of gamma ray sources, e.g., uranium, and the like. The apparatus comprises a first light guide, optically coupled to a first optical detector; a second light guide, optically coupled to a second optical detector a sheet of neutron scintillator, opaque for incoming optical photons, said sheet of neutron scintillator sandwiched between the first and the second light guides. The second light guide comprises a gamma ray scintillator material.

A method for determining at least one formation property calculated from neutron measurements acquired with a downhole tool includes emitting neutrons from a source in the tool into the formation, detecting neutrons with at least one detector in the downhole tool, calculating a first slowing-down length (L1) based on the detected neutrons, and deriving a second slowing-down length (L2) based on the first slowing-down length (L1). Further steps include deriving a correlation function for relating slowing-down lengths from a first tool to slowing-down lengths associated with a different source, wherein the correlation function depends on formation properties such as bulk density; and applying the correlation function to the slowing-down length of the first tool to derive the slowing-down length of the second tool. A method for determining a thermal neutron formation porosity based on a slowing-down length from epithermal neutron measurements from an electronic neutron source includes converting the slowing-down length into a computed neutron slowing-down length from thermal neutron measurements from a chemical neutron source, wherein the converting uses a correlation function that depends on formation bulk density; deriving a thermal neutron countrate ratio based on the computed neutron slowing-down length, wherein the deriving uses a function that depends on the formation bulk density and formation sigma; and computing the thermal neutron formation porosity from the thermal neutron countrate ratio.

A thermal neutron detector includes a planar detector housing having two glass panels spaced apart by a gas-tight seal defining a detection chamber including an inert detection gas and lithium foils adhered to inner surfaces of the glass panel(s). The lithium foils emit alpha particles and tritons in response to incident thermal neutrons, and the inert detection gas is ionized by the particles to generate drift electrons. A planar array of detection wires is spaced apart from the lithium foils and extends outside the detection chamber. Electronic bias applies a field voltage between the wires and the lithium foils to establish a drift electric field in the detection chamber effective to attract the drift electrons to the wires and provide a large electric field near the anode wires to cause electron multiplication near the wire resulting in large numbers of electrons and positive ions for each initial electron. Detection circuitry detects electric signals in wires generated by the drift of positive ions away from the wires and interpret the electrical signals as incidence of thermal neutrons on the detector.

The present invention discloses a methodology for the characterization and determination of mixed-field dosimetry for 252Cf Applicator Tube (AT)-type medical sources, utilizing ionization chambers, GM counters, and Monte Carlo methods. Unlike the previous methodologies, the present invention discloses a specification of dose to muscle, rather than dose to water, for clinical dosimetry of 252Cf medical sources. A dosimetry protocol, similar to that utilized for ICRU-45, with parameters determined specifically for 252Cf brachytherapy is disclosed. Neutron isodose distributions and data necessary for clinical implementation of 252Cf AT sources are also disclosed herein. Additionally, novel methods for the encapsulation, storage, and delivery / implantation of 252Cf radionuclide sources are disclosed.

A neutron imaging method for obtaining an image of the general shape of a neutron emitting source and a bearing of the source relative to an apparatus comprising a chamber comprising a gas with a high probability of interacting with low energy neutrons, releasing collision products that maintain the neutron momentum, and generating ionization particles. The chamber comprises an electrode for providing an electronic signal indicative of the impact location of ionization particles on the electrode and a field to drift the ionization particles to the electrode. A readout indicates the location and time of impact of each ionization particle on the electrode; a memory stores a plurality of the electronic signals; and a computer receives and analyzes the signals and impact times and indicates the location of the source of neutrons by using back projection algorithms to calculate three-dimensional vectors indicative of the neutron path directions.

An apparatus for selective radiation detection includes a neutron detector that facilitates detection of neutron emitters, e.g. plutonium, and the like; a gamma ray detector that facilitates detection of gamma ray sources, e.g., uranium, and the like; and / or an X-ray analyzer that facilitates detection of materials that can shield radioactiv sources, e.g., lead, and the like.

A system for measuring a thermal neutron emission from a neutron source is provided. The system employs a detector utilizing a plurality of doped pBN layers, wherein the doped pBN layers are doped with at least one dopant across an a-b plane of the layers for an electrical resistivity of 1014 ohm-cm or less.

A thermal neutron detector includes a planar detector housing having two glass panels spaced apart by a gas-tight seal defining a detection chamber. Lithium foils adhered to inner surfaces of the glass panel emit alpha particles and tritons in response to incident thermal neutrons, and an inert detection gas is ionized to generate drift electrons. A planar array of detection wires is spaced from the lithium foils and extends outside the detection chamber. Electronic bias applies a field voltage between the wires and the lithium foils to establish a drift electric field to attract the drift electrons to the wires and provide a large electric field to cause electron multiplication. Detection circuitry detects electric signals in the wires generated by the drift of positive ions away from the wires and interprets the electrical signals as incidence of thermal neutrons on the detector.

In one example, a radiation source comprises a housing and an acceleration chamber within the housing, with a peak acceleration energy greater than the lowest neutron production threshold of tantalum. A source of charged particles is supported by the housing to emit charged particles into the acceleration chamber. A target is supported by the housing downstream of the acceleration chamber. The target consists essentially of at least one isotope having a neutron production threshold greater than the peak acceleration energy. No neutrons are therefore generated. The source may also comprise a collimator, target shielding, and / or housing shielding comprising at least one isotope having a neutron production threshold greater than the peak acceleration energy, reducing or eliminating neutron generation as compared to the prior art, as well. Systems comprising the source, methods of operation of the source, and methods of manufacture of the source are also disclosed.

A detector for detecting the presence of suspect radionuclides in a target is disclosed. The detector includes a first detection channel for a first detecting neutron emissions in the target and for providing a first output in accordance with the first detecting, a second detection channel for a second detecting x-ray emissions in the target and for providing a second output in accordance with the second detecting, a third detection channel for a third detecting and an identifying of gamma emissions in the target and for providing a third output in accordance with the third detecting and identifying, a signal manipulation electrically coupled to each of the first, second, and third detection channels, the signal manipulation for receiving the first, second and third outputs and for processing those outputs, and at least one processor electrically coupled to the signal manipulation. The processor determines if the suspect radionuclide is present in the target and provides an alert when the suspect radionuclide is present in the target.

The invention discloses a primary neutron source part for starting a nuclear reactor. The primary neutron source part comprises a cladding tube, a neutron source, cushion blocks, an upper end plug and a lower end plug, wherein the neutron source is arranged in the cladding tube; two ends of the cladding tube are respectively sealed by the upper end plug and the lower end plug; the neutron source is a Cf-252 neutron source of which neutron emission rate is 1.0*10<8> to 1.0*10<10> n / s; and a compression cushion block and a supporting cushion block are arranged on two sides of the neutron source. The primary neutron source part for starting the nuclear reactor provided by the invention is simple in structure, safe, reliable and easy to process.