According to an embodiment, a neutron measurement apparatus has: a neutron detector; a preamplifier that amplifies an output signal of the neutron detector and outputs a neutron detection signal; a pulse counting unit that measures the neutron intensity by using pulse counting method by which the neutron detection signal is used to count the number of individual pulses; a Campbell measurement unit that measures the neutron intensity by using Campbell method by which a time average of squares of AC component of the neutron detection signal is calculated; a correction constant calculation unit that calculates a correction constant for correcting an output of the Campbell measurement unit by using an output of the pulse counting unit and an output of the Campbell measurement unit; and a correction value calculation unit that outputs, based on the output of the Campbell measurement unit, a corrected value by using the correction constant.

According to an embodiment, a neutron measurement apparatus has: a neutron detector; a preamplifier that amplifies an output signal of the neutron detector and outputs a neutron detection signal; a pulse counting unit that measures the neutron intensity by using pulse counting method by which the neutron detection signal is used to count the number of individual pulses; a Campbell measurement unit that measures the neutron intensity by using Campbell method by which a time average of squares of AC component of the neutron detection signal is calculated; a correction constant calculation unit that calculates a correction constant for correcting an output of the Campbell measurement unit by using an output of the pulse counting unit and an output of the Campbell measurement unit; and a correction value calculation unit that outputs, based on the output of the Campbell measurement unit, a corrected value by using the correction constant.

An apparatus for neutron detection is provided. The apparatus comprises a sensor medium in electrical contact with an electrode arrangement conformed to collect radiation-generated charge from the sensor medium. The sensor medium comprises a borazine and/or a borazine-based polymer.

A neutron detector for detecting neutrons includes an exterior shell bounding and sealing an interior volume. The exterior shell serves as a cathode. A central structure extends longitudinally within the exterior shell. The central structure serves as an anode and is maintained at a first voltage. The neutron detector includes an insulating portion extending between the central structure and the exterior shell and longitudinally past a shell end of the exterior shell towards a structure end of the central structure. A guard structure extends circumferentially around an outer insulating surface. The guard structure is positioned on the insulating portion between the shell end and the structure end. The guard structure is maintained at a second voltage such that a leakage current on the outer insulating surface is absorbed by the guard structure. A method of detecting neutrons with the neutron detector is also provided.

A neutron detector for detecting neutrons includes an exterior shell bounding and sealing an interior volume. The exterior shell serves as a cathode. A central structure extends longitudinally within the exterior shell. The central structure serves as an anode and is maintained at a first voltage. The neutron detector includes an insulating portion extending between the central structure and the exterior shell and longitudinally past a shell end of the exterior shell towards a structure end of the central structure. A guard structure extends circumferentially around an outer insulating surface. The guard structure is positioned on the insulating portion between the shell end and the structure end. The guard structure is maintained at a second voltage such that a leakage current on the outer insulating surface is absorbed by the guard structure. A method of detecting neutrons with the neutron detector is also provided.

Gas-filled neutron detectors, an imaging system and an array of such detectors are provided. Surfaces or surface portions incorporated into the gas-filled neutron detectors are coated with and/or composed of at least partially, neutron reactive material. The surfaces may be flat or curved, fins or plates, foils, thin sheets, porous or filamentary material, or semi-solid material or aerogel. The incorporation of the extended surfaces coated with or composed of neutron reactive material increases the neutron detection efficiency of the gas-filled detectors. The surfaces can be made of conductive, semiconductive, semi-insulating, or insulative materials. The surfaces are arranged such that they do not detrimentally detract from the main function of a gas-filled detector with particular attention to gas-filled proportional detectors. The surfaces may be arranged in the detectors to allow for modular construction. The surfaces are designed and arranged such that more than a single reaction product may escape the surface.

Gas-filled neutron detectors, an imaging system and an array of such detectors are provided. Surfaces or surface portions incorporated into the gas-filled neutron detectors are coated with and/or composed of at least partially, neutron reactive material. The surfaces may be flat or curved, fins or plates, foils, thin sheets, porous or filamentary material, or semi-solid material or aerogel. The incorporation of the extended surfaces coated with or composed of neutron reactive material increases the neutron detection efficiency of the gas-filled detectors. The surfaces can be made of conductive, semiconductive, semi-insulating, or insulative materials. The surfaces are arranged such that they do not detrimentally detract from the main function of a gas-filled detector with particular attention to gas-filled proportional detectors. The surfaces may be arranged in the detectors to allow for modular construction. The surfaces are designed and arranged such that more than a single reaction product may escape the surface.

A Disclosed is a long-lifespan in-core instrument having an extended lifespan due to an enhanced combustion lifespan of an emitter. A central tube and an outer sheath tube distanced from the outer circumferential surface of the central tube are provided. Self-powered neutron detectors are placed between the central tube and outer sheath tube. Each self-powered neutron detector includes an emitter of a material having a neutron reaction cross section that is comparatively smaller than that of rhodium. A background detector for compensating for the background noise signal; core exit thermocouples for detecting the core exit temperature; and filler wires filling in the space between the self-powered neutron detectors, background detector and core exit thermocouples are provided.

A Disclosed is a long-lifespan in-core instrument having an extended lifespan due to an enhanced combustion lifespan of an emitter. A central tube and an outer sheath tube distanced from the outer circumferential surface of the central tube are provided. Self-powered neutron detectors are placed between the central tube and outer sheath tube. Each self-powered neutron detector includes an emitter of a material having a neutron reaction cross section that is comparatively smaller than that of rhodium. A background detector for compensating for the background noise signal; core exit thermocouples for detecting the core exit temperature; and filler wires filling in the space between the self-powered neutron detectors, background detector and core exit thermocouples are provided.

A local area cosmogenic neutron sensor is used for detecting moisture within a measurement surface. A neutron detector is positioned on a stand structure holding the detector above a measurement surface. A moderator material and neutron shield are positioned around at least a portion of the neutron detector. The neutron shield substantially covers lateral sides and an entirety of a top of the neutron detector and is not positioned on a bottom side of the neutron detector. A thermal neutron shield is positioned below the neutron detector and in a path of neutron travel between the measurement surface and the neutron detector to substantially block environmental thermal neutrons from reaching the neutron detector, which improves the signal-to-noise ratio and signal contrast of the local area cosmogenic neutron sensor.