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 non-destructive inspection system 1 includes a neutron radiation source 3 capable of emitting neutrons N, and a neutron detector 14 capable of detecting neutrons Nb produced via an inspection object 6a among neutrons N emitted from the neutron radiation source 3. The neutron radiation source 3 includes a linear accelerator 11 capable of emitting charged particles P accelerated; a first magnet section 12 including magnets 12a and 12b facing each other, the magnets 12a and 12b being capable of deflecting the charged particles P in a direction substantially perpendicular to a direction of emission of the charged particles P from the linear accelerator 11; and a target section 13 capable of producing neutrons N by being irradiated with the charged particles P that have passed through the first magnet section 12.

In a general aspect, a collimator system is described. In some aspects, a neutron beam collimation method includes receiving a neutron beam from a neutron source; polarizing the neutron beam using a polarizer, and obtaining a collimated neutron beam from the polarized neutron beam. The neutron beam generated by the neutron source has a first beam divergence and includes a plurality of neutrons. The collimated neutron beam has a second beam divergence that is less than the first beam divergence. Obtaining the collimated neutron beam includes mapping transverse momentum of each respective neutron, of the plurality of neutrons, onto a polarization degree of freedom of the respective neutron by applying a sequence of phase shift gradients to the polarized neutron beam, and after applying the sequence of phase shift gradients, passing the polarized neutron beam through an analyzer.

The subject matter described herein includes methods, systems, and computer program products for measuring the density of a material. According to one aspect, a material property gauge includes a nuclear density gauge for measuring the density of a material. A radiation source adapted to emit radiation into a material and a radiation detector operable to produce a signal representing the detected radiation. A first material property calculation function may calculate a value associated with the density of the material based upon the signal produced by the radiation detector. The material property gauge includes an electromagnetic moisture property gauge that determines a moisture property of the material. An electromagnetic field generator may generate an electromagnetic field where the electromagnetic field sweeps through one or more frequencies and penetrates into the material. An electromagnetic sensor may determine a frequency response of the material to the electromagnetic field across the several frequencies.

Provided herein are systems and methods for generating a plurality of different monoenergetic neutron energies using a plurality of interchangeable ion beam targets. In certain embodiments, each of the plurality of ion beam targets is configured to generate a monoenergetic energy value that is at least 100 kiloelectron volts (keV) different from the other ion beam targets. In some embodiments, the ion beam targets are composed of LiF, TiD.sub.1.5-1.8, TiT.sub.1-2, ErD.sub.1.5, ErT, or Li.

A neutron imaging device employs a neutron source including a sealed enclosure, gamma ray detector(s) spaced from the neutron source, and particle detector(s) disposed in the sealed enclosure of the neutron source. The output of the particle detector(s) can be used to obtain a direction of particles generated by the neutron source and corresponding directions of neutrons generated by the neutron source. Such information can be processed to determine locations in the surrounding borehole environment where the secondary gamma rays are generated and determine data representing formation density at such locations. In one aspect, the gamma ray detector(s) of the neutron imaging device can include at least one scintillation crystal with shielding disposed proximate opposite ends of the scintillation crystal. In another aspect, the particle detector(s) of the neutron imaging device can include a resistive anode encoder having a ceramic substrate and resistive glaze.

A neutron imaging system that includes a central neutron source configured to produce source neutrons, wherein the central neutron source comprises a beam target, a moderator chamber surrounding at least a portion of the beam target, the moderator chamber housing a moderator, and a re-entrant cone extending into the moderator chamber. The re-entrant cone includes an entrance surface facing the beam target. The entrance surface encloses a cone chamber, isolating the cone chamber from the moderator. Furthermore, the entrance surface is shaped such that source neutrons produced at the beam target impinge the entrance surface with a neutron flux that varies by 10% or less along the entrance surface.

A neutron imaging system that includes a central neutron source configured to produce source neutrons, wherein the central neutron source comprises a beam target, a moderator chamber surrounding at least a portion of the beam target, the moderator chamber housing a moderator, and a re-entrant cone extending into the moderator chamber. The re-entrant cone includes an entrance surface facing the beam target. The entrance surface encloses a cone chamber, isolating the cone chamber from the moderator. Furthermore, the entrance surface is shaped such that source neutrons produced at the beam target impinge the entrance surface with a neutron flux that varies by 10% or less along the entrance surface.

A non-destructive inspection system 1 includes a neutron radiation source 3 capable of emitting neutrons N, and a neutron detector 14 capable of detecting neutrons Nb produced via an inspection object 6a among neutrons N emitted from the neutron radiation source 3. The neutron radiation source 3 includes a linear accelerator 11 capable of emitting charged particles P accelerated; a first magnet section 12 including magnets 12a and 12b facing each other, the magnets 12a and 12b being capable of deflecting the charged particles P in a direction substantially perpendicular to a direction of emission of the charged particles P from the linear accelerator 11; and a target section 13 capable of producing neutrons N by being irradiated with the charged particles P that have passed through the first magnet section 12.

Methods, systems, and computer program products for determining a property of construction material. According to one aspect, a material property gauge operable to determine a property of construction material is disclosed. The gauge may include an electromagnetic sensor operable to measure a response of construction material to an electromagnetic field. Further, the electromagnetic sensor may be operable to produce a signal representing the measured response by the construction material to the electromagnetic field. An acoustic detector may be operable to detect a response of the construction material to the acoustical energy. Further, the acoustic detector may be operable to produce a signal representing the detected response by the construction material to the acoustical energy. A material property calculation function may be configured to calculate a property value associated with the construction material based upon the signals produced by the electromagnetic sensor and the acoustic detector.