Neutron Generator

摘要

A neutron generator includes an ion source disposed in a pressurized environment containing an ionizable gas. The ion source includes a substrate with a bundle of carbon nanotubes extending therefrom. The ends of the nanotubes are spaced from a grid. Ion source voltage supply circuitry supplies a positive voltage potential between the substrate and the grid of the ion source to cause ionization of the ionizable gas and emission of ions through the grid. An ion accelerator section is disposed between the ion source and a target. The ion accelerator section accelerates ions that pass through the grid towards the target such that collisions of the ions with the target cause the target to generate and emit neutrons therefrom. The ion source, accelerator section and target are housed in a sealed tube and preferably the carbon nanotubes of the bundle are highly ordered with at least 106 carbon nanotubes per cm2 that extend in a direction substantially parallel to the central axis of the tube. The neutron generator provides gas ionization at much higher atomic to molecular ratio that the prior art, which allows for small compact size designs suitable for logging tools that are used in space-constrained downhole environments.

主权项

1. A neutron generator comprising:
an insulative housing defining a sealed chamber having a central axis; an ionizable gas supply carried by the insulative housing to provide an ionizable gas within the sealed chamber; an ion source disposed in the sealed chamber adjacent the ionizable gas supply and defining a gas diffusion space therebetween, the ion source including a grid and a substrate that has a plurality of conductive field-emitting tips extending therefrom in a direction substantially parallel to the central axis of the sealed chamber, away from the diffusion space, and that are spaced from the grid; conductive flanges carried by the insulative housing and respectively coupled to the grid and the substrate; an ion source voltage supply electrically coupled to the substrate and the grid via the respective conductive flanges to supply a positive voltage potential between the substrate and the grid, thereby causing electrons from gas molecules of the ionizable gas to quantum tunnel to the field-emitting tips of the substrate so as to cause ionization of the ionizable gas proximate the field-emitting tips of the substrate; a target disposed within the sealed chamber; and an accelerator section disposed within the sealed chamber between the ion source and the target that accelerates ions that pass through the grid towards the target such that collisions of ions with the target cause the target to generate and emit neutrons therefrom.