A .sup.3Helium gas counter comprising polyethylene slabs, a rectangular gas tube within the polyethylene slabs, and a mixture of .sup.3Helium and Xenon. A .sup.3Helium gas counter comprising polyethylene slabs, a rectangular gas tube within the polyethylene slabs, and a mixture of .sup.3Helium and Krypton. A method of making a .sup.3Helium gas counter comprising providing polyethylene slabs, placing a rectangular gas tube within the polyethylene slabs, and depositing a mixture of .sup.3Helium and Xenon into the rectangular gas tube.

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.

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 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.

A fissile neutron detection system includes an ionizing thermal neutron detector arrangement including an inner peripheral shape that at least substantially surrounds a moderator region for detecting thermal neutrons that exit the moderator region but is at least generally transparent to the incident fissile neutrons. A moderator is disposed within the moderator region having lateral extents such that any given dimension that bisects the lateral extents includes a length that is greater than any thickness of the moderator arrangement transverse to the lateral extents. The moderator can include major widthwise and major lengthwise lateral extents such that any given dimension across the lengthwise and widthwise lateral extents includes a length that is greater than any thickness of the moderator arrangement transverse to the lateral extents.

A detector of thermal neutrons, fast neutrons and gamma photons that is based on a Cherenkov radiation detector in water and that allows large active volumes of detection at a relatively low cost and higher intensity signals, wherein said detector comprises a container comprising at least a lid; a photon reflective and diffusive coating inside the container; an aqueous solution contained in the container, which comprises sodium chloride (NaCl); and a light sensing device optically coupled to the aqueous solution.

A device for measuring the energy of neutrons incident in a first direction is provided. The device comprises a gas between a cathode and an anode, the anode comprising a matrix array of electron detectors, the first direction being orthogonal to the anode-cathode direction.

A measuring device includes an ionization chamber where air is contained and a measurement value relating to radiation including a neutron ray and a gamma ray is measured, a detector that detects a detection value relating to the neutron ray, and a controller that calculates a dose of the gamma ray based on the measurement value measured in the ionization chamber and the detection value detected by the detector.

A lightweight neutron dosimeter is disclosed. The dosimeter comprises a cylindrical body acting as moderator, an active component acting as neutron detector and neutron filters. The neutron filters are formed by at least two crowns placed inside the moderator, a first of said crowns being placed adjacent to the active component and a second crown being placed between the first crown and an inner wall surface of the moderator. The first crown includes top and bottom caps to cover open ends of the first crown, the top cap having an opening to allow introduction of the active component therein and a thickness of the top and bottom caps being the same as the thickness of the two crowns. The first and second crowns comprises vertical ribbons, an area covered by the plurality of vertical ribbons in each crown, excluding the top and bottom caps, being comprised in a range between 50-95%.