Abstract: The disclosed embodiments include downhole neutron generators and methods to utilize downhole neutron generators in a downhole environment. In one embodiment, a downhole neutron generator includes a heating element to dissipate heat to a first transition metal, which heats up the first transition metal and facilitates the first transition metal to absorb deuterium and tritium gases flowing proximate said transition metal. The downhole neutron generator also includes a second transition metal separated from the target foil, where the second transition metal is doped with of deuterium and the tritium ions, and a laser to direct optical pulses onto a surface of the first transition metal to produce deuterium and the tritium ions from the absorbed deuterium and tritium, where said ions traverse through a back surface of the first transition metal to the second transition metal to interact with the doped deuterium and the tritium ions to initiate fusion reaction.

Abstract: A neutron generator includes a gas control interface and a vacuum chamber coupled to the gas control interface. The neutron generator also includes a target rod disposed within the vacuum chamber and having a longitudinal axis aligned with a central axis of the vacuum chamber, and further including a target disposed on a surface of the target rod facing the getter. The neutron generator also includes a planar ion source adjacent to the gas control interface and disposed between the target and the gas control interface. The planar ion source includes an array grid that is offset from the target and generally perpendicular to the longitudinal axis of the target rod.

Abstract: Described herein are neutron generators that employ direct field ionization of ionizable fusion gases, as well as well-logging tools and methods that utilize such neutron generators. In various embodiments, the neutron generator includes a cylindrical field-ionization structure distributed around the inner surface of a tubular housing, and a cylindrical ion-accelerating grid disposed about the longitudinal axis concentrically to the field-ionization structure. Ions generated by the field-ionization structure may accumulate inside the ion-accelerating grid, from which they can be axially extracted and accelerated towards a fusion target. Additional tools, systems, and methods are disclosed.

Abstract: An accelerator neutron source (ANS) including a field ionization (FI) array configured to generate deuterium and tritium ions and a plasma for containing the deuterium and tritium ions produced by the FI array. The ANS also includes a target comprising deuterium and tritium ions and the ANS is configured to accelerate deuterium and tritium ions produced by the FI array toward the target to generate neutrons by applying a voltage to an accelerating electrode.

Abstract: A well logging tool includes a neutron generator having an ion source cathode comprising a nano-structure field emission (FE) array for producing a charged particle current routed through an ionizable gas, thus generating ions by electron impact ionization of the gas. The nanostructures can be provided by bundles of silicon nanotips grown on a substrate. The FE array can be provided on an axially facing substrate located co-axially in an elongate housing, with the charged particle current directed from the centrally located FE array to a co-axial annular anode and having axial and radial directional components.

Abstract: A neutron generator includes a gas control interface and a vacuum chamber coupled to the gas control interface. The neutron generator also includes a target rod disposed within the vacuum chamber and having a longitudinal axis aligned with a central axis of the vacuum chamber, and further including a target disposed on a surface of the target rod facing the getter. The neutron generator also includes a planar ion source adjacent to the gas control interface and disposed between the target and the gas control interface. The planar ion source includes an array grid that is offset from the target and generally perpendicular to the longitudinal axis of the target rod.

Abstract: A neutron generator includes a gas control interface and a vacuum chamber coupled to the gas control interface. The neutron generator also includes a target rod disposed within the vacuum chamber and having a longitudinal axis aligned with a central axis of the vacuum chamber, and further including a target disposed on a surface of the target rod facing the getter. The neutron generator also includes a planar ion source adjacent to the gas control interface and disposed between the target and the gas control interface. The planar ion source includes an array grid that is offset from the target and generally perpendicular to the longitudinal axis of the target rod.

Abstract: The disclosed embodiments include downhole gamma-ray generators and methods to utilize downhole gamma-ray generators in a downhole environment. In one embodiment, a downhole gamma-ray generator includes a target foil formed from a first material. The downhole gamma-ray generator also includes a second layer deposited along a back surface of the target foil. The downhole gamma-ray generator further includes a laser system operable to direct optical pulses onto a front surface of the target foil to ionize atoms of the first material, where electrons produced by ionization of the first material propagate through the target foil and decelerates when the electrons interact with the high density material, and where the deceleration of the electrons produces gamma-rays that are utilized to obtain one or more formation properties of a downhole formation.

Abstract: Various embodiments include apparatus and methods of using the apparatus having a neutron generator. The neutron generator can include a neutron generator tube having a cylindrical inner surface that bounds a cylindrical cavity, a field ionization array cylindrically distributed on the cylindrical inner surface, and a target rod positioned in the cylindrical cavity. Additional apparatus, systems, and methods are disclosed.

Abstract: The disclosed embodiments include downhole neutron generators and methods to utilize downhole neutron generators in a downhole environment. In one embodiment, a downhole neutron generator includes a heating element to dissipate heat to a first transition metal, which heats up the first transition metal and facilitates the first transition metal to absorb deuterium and tritium gases flowing proximate said transition metal. The downhole neutron generator also includes a second transition metal separated from the target foil, where the second transition metal is doped with of deuterium and the tritium ions, and a laser to direct optical pulses onto a surface of the first transition metal to produce deuterium and the tritium ions from the absorbed deuterium and tritium, where said ions traverse through a back surface of the first transition metal to the second transition metal to interact with the doped deuterium and the tritium ions to initiate fusion reaction.

Abstract: A well logging tool includes a neutron generator having a housing, a gas source, a field ionization array, and an extraction ring. The housing defines an ion source chamber, and the gas source delivers ionizable gas to the ion source chamber. The field ionization array directly ionizes the ionizable gas to produce ions in the ion source chamber. The extraction ring produces an ion beam using the ions to initiate a fusion reaction that results in neutron emission from the neutron generator. Additional apparatus, methods, and systems are disclosed.

Abstract: A neutron generator includes a gas control interface and a vacuum chamber coupled to the gas control interface. The neutron generator also includes a target rod disposed within the vacuum chamber and having a longitudinal axis aligned with a central axis of the vacuum chamber, and further including a target disposed on a surface of the target rod facing the getter. The neutron generator also includes a planar ion source adjacent to the gas control interface and disposed between the target and the gas control interface. The planar ion source includes an array grid that is offset from the target and generally perpendicular to the longitudinal axis of the target rod.

Abstract: The disclosed embodiments include downhole gamma-ray generators and methods to utilize downhole gamma-ray generators in a downhole environment. In one embodiment, a downhole gamma-ray generator includes a target foil formed from a first material. The downhole gamma-ray generator also includes a second layer deposited along a back surface of the target foil. The downhole gamma-ray generator further includes a laser system operable to direct optical pulses onto a front surface of the target foil to ionize atoms of the first material, where electrons produced by ionization of the first material propagate through the target foil and decelerates when the electrons interact with the high density material, and where the deceleration of the electrons produces gamma-rays that are utilized to obtain one or more formation properties of a downhole formation.

Abstract: Described herein are neutron generators that employ direct field ionization of ionizable fusion gases, as well as well-logging tools and methods that utilize such neutron generators. In various embodiments, the neutron generator includes a cylindrical field-ionization structure distributed around the inner surface of a tubular housing, and a cylindrical ion-accelerating grid disposed about the longitudinal axis concentrically to the field-ionization structure. Ions generated by the field-ionization structure may accumulate inside the ion-accelerating grid, from which they can be axially extracted and accelerated towards a fusion target. Additional tools, systems, and methods are disclosed.

Abstract: A well logging tool includes a neutron generator to generate and emit energetic neutrons using substantially exclusively a T-T fusion reaction. The well logging tool can include measuring instrumentation for measurement and logging of formation parameters based on elastic scattering in subsurface formations of neutrons emitted by the neutron generator. The neutron generator can have a concentric layout, in which a cylindrical target structure loaded with tritium particles is located co-axially in an elongate cylindrical housing, with mobile tritium ions being accelerated radially inwardly into impact with the target structure. Production of the mobile tritium ions may be by field ionization through operation of a nano-structure field ionization array.

Abstract: An accelerator neutron source (ANS) including a field ionization (FI) array configured to generate deuterium and tritium ions and a plasma for containing the deuterium and tritium ions produced by the FI array. The ANS also includes a target comprising deuterium and tritium ions and the ANS is configured to accelerate deuterium and tritium ions produced by the FI array toward the target to generate neutrons by applying a voltage to an accelerating electrode.

Abstract: A well logging tool includes a neutron generator having an ion source for ion production by electron impact ionization wherein ionization current trajectory is determined by an electric field and an at least partially misaligned magnetic field. The electric field can be provided by an electrode arrangement having a cathode associated with a field emitter array including a multitude of nanoemitters. The magnetic field can be provided by a permanent magnet incorporated in the neutron generator to act transversely to the electric field in at least part of an ion source chamber in which an ionization current emitted by the field emitter array travels through an ionizable gas. Charged particles traveling through the ionizable gas thus follow respective trajectories that are longer than would be the case in the absence of the magnetic field, thereby increasing ionization probability.

Abstract: A well logging tool includes a neutron generator having an ion source for ion production by electron impact ionization wherein ionization current trajectory is determined by an electric field and an at least partially misaligned magnetic field. The electric field can be provided by an electrode arrangement having a cathode associated with a field emitter array including a multitude of nanoemitters. The magnetic field can be provided by a permanent magnet incorporated in the neutron generator to act transversely to the electric field in at least part of an ion source chamber in which an ionization current emitted by the field emitter array travels through an ionizable gas. Charged particles traveling through the ionizable gas thus follow respective trajectories that are longer than would be the case in the absence of the magnetic field, thereby increasing ionization probability.

Abstract: A well logging tool includes a neutron generator to generate and emit energetic neutrons using substantially exclusively a T-T fusion reaction. The well logging tool can include measuring instrumentation for measurement and logging of formation parameters based on elastic scattering in subsurface formations of neutrons emitted by the neutron generator. The neutron generator can have a concentric layout, in which a cylindrical target structure loaded with tritium particles is located co-axially in an elongate cylindrical housing, with mobile tritium ions being accelerated radially inwardly into impact with the target structure. Production of the mobile tritium ions may be by field ionization through operation of a nano-structure field ionization array.

Abstract: A well logging tool includes a neutron generator having an ion source cathode comprising a nano-structure field emission (FE) array for producing a charged particle current routed through an ionizable gas, thus generating ions by electron impact ionization of the gas. The nanostructures can be provided by bundles of silicon nanotips grown on a substrate. The FE array can be provided on an axially facing substrate located co-axially in an elongate housing, with the charged particle current directed from the centrally located FE array to a co-axial annular anode and having axial and radial directional components.