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 fissile neutron detection system includes a neutron moderator and a neutron detector disposed proximate such that a majority of the surface area of the neutron moderator is disposed proximate the neutron detector. Fissile neutrons impinge upon and enter the neutron moderator where the energy level of the fissile neutron is reduced to that of a thermal neutron. The thermal neutron may exit the moderator in any direction. Maximizing the surface area of the neutron moderator that is proximate the neutron detector beneficially improves the reliability and accuracy of the fissile neutron detection system by increasing the percentage of thermal neutrons that exit the neutron moderator and enter the neutron detector.

Embodiments of the present disclosure include a system for detecting neutrons with a housing, a gas chamber at least partially defined by the housing, an anode extending through at least a portion of the gas chamber, and a pseudogas arranged within the gas chamber. The pseudogas comprises a mixture of gas and suspended solid particles that contain an element with a high cross-section for thermal neutron capture.

The present invention relates to a neutron detector that for the first time permits the construction of large detector areas of approximately 1 m.sup.2 to 2 m.sup.2, with a spatial resolution of the neutrons of under 2 mm. It is additionally possible in the case of the modular construction in a stack arrangement to attain detection sensitivities that are comparable to .sup.3He counter tubes (ca. 60%) or, with a greater number of detector elements, higher. By using thin substrate plates—such as aluminum sheets—and omission of the external pressure vessels, the neutron detectors are relatively lightweight despite their large dimensions and can be produced inexpensively.

The neutron detector comprises at least one module (detector element) comprising in each case two mutually parallel substrate plates made from a first neutron-transparent material, with said plates being spanned in each case on a self-supporting frame made of a second neutron-transparent material and being coated with a neutron absorber material on a side that is remote from the self-supporting frame, wherein the side that is coated with a neutron absorber material faces the respectively other substrate plate on an inner side, and a gas-tight measurement space, which is filled with a counter gas and in which two electrode wire planes, arranged parallel to the substrate plates, having electrode wires that run parallel in the respective electrode wire planes are arranged and in which the electrode wire planes are spaced apart from one another by way of a spacer frame, is defined between the mutually facing, coated inner sides of the substrate plates. The modules can be arranged successively in a stack arrangement.

The present invention relates to a neutron detector that for the first time permits the construction of large detector areas of approximately 1 m.sup.2 to 2 m.sup.2, with a spatial resolution of the neutrons of under 2 mm. It is additionally possible in the case of the modular construction in a stack arrangement to attain detection sensitivities that are comparable to .sup.3He counter tubes (ca. 60%) or, with a greater number of detector elements, higher. By using thin substrate plates—such as aluminum sheets—and omission of the external pressure vessels, the neutron detectors are relatively lightweight despite their large dimensions and can be produced inexpensively. The neutron detector comprises at least one module (detector element) comprising in each case two mutually parallel substrate plates made from a first neutron-transparent material, with said plates being spanned in each case on a self-supporting frame made of a second neutron-transparent material and being coated with a neutron absorber material on a side that is remote from the self-supporting frame, wherein the side that is coated with a neutron absorber material faces the respectively other substrate plate on an inner side, and a gas-tight measurement space, which is filled with a counter gas and in which two electrode wire planes, arranged parallel to the substrate plates, having electrode wires that run parallel in the respective electrode wire planes are arranged and in which the electrode wire planes are spaced apart from one another by way of a spacer frame, is defined between the mutually facing, coated inner sides of the substrate plates. The modules can be arranged successively in a stack arrangement.

A device for detecting neutrons comprising a base, a lateral surface and a cover, thereby providing a detector housing having a central longitudinal axis, wherein the interior of the housing is divided into n (n≥2) cells wherein at least one of said cells is adapted to operate as neutron detection ion chamber by having at least one removable foil disposed parallel to said longitudinal axis, at least one removable foil positioned adjacent to, and essentially parallel with, a sector of the lateral surface, with said removable foils having neutron sensitive coating applied on at least one their faces, and an anode mounted in at least one cell bounded by said removable foils, with said housing constituting the cathode. The device is also useful for simultaneously detecting gamma irradiation and or producing radioisotopes.

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 narrow thermal neutron detector includes a slidably receivable ionization thermal neutron detector module within an overall housing body. An active sheet layer of the ionization thermal neutron detector module can be tensioned across its width. The ionization thermal neutron detector module can include module upper major surface extents and module lower surface extents such that, when installed within the housing body, the module upper major surface extents are in a first spaced apart confronting relationship with housing upper major surface extents to define a first clearance and module lower major surface extents are in a second spaced apart confronting relationship with housing lower major surface extents to define a second clearance to accommodate housing flexing due to ambient pressure change. The housing body can be formed with a single opening for receiving the ionization thermal neutron detection module or with opposing first and second opposing end openings.

To address the shortcomings presented in the prior art, the present invention provides a system and method to provide improved irrigation management through the detection of fast neutrons. According to a preferred embodiment, the fast neutron detector of the present invention includes a 4-He based noble gas detector, a power source, a signal processing circuit, and a resistor in series with a preamplifier and a shaping amplifier to produce a processed signal. According to a further preferred embodiment, the present invention preferably further includes a signal channel analyzer and a pulse counter/rate meter. According to a further preferred embodiment, the present invention includes a controller which receives a count of detected fast neutrons and translates the detected number of fast neutrons into an irrigation map indicating the required levels of irrigation needed for selected areas of a given field based on the detected moisture levels.

A fissile neutron detection system includes a neutron moderator and a neutron detector disposed proximate such that a majority of the surface area of the neutron moderator is disposed proximate the neutron detector. Fissile neutrons impinge upon and enter the neutron moderator where the energy level of the fissile neutron is reduced to that of a thermal neutron. The thermal neutron may exit the moderator in any direction. Maximizing the surface area of the neutron moderator that is proximate the neutron detector beneficially improves the reliability and accuracy of the fissile neutron detection system by increasing the percentage of thermal neutrons that exit the neutron moderator and enter the neutron detector.