NANO-EMITTER ION SOURCE NEUTRON GENERATOR

摘要

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.

主权项

1. A neutron generator comprising:
a housing configured for incorporation in a subsurface logging tool, the housing defining an ion source chamber for holding an ionizable gas; a nano-emitter arrangement comprising multiple nano-emitters located in the ion source chamber and configured for emitting electrons into the ion source chamber; an electrode arrangement configured to provide an electric field in the ion source chamber for propelling the emitted electrons through the ionizable gas, to cause ion production by electron impact ionization of the ionizable gas; and a permanent magnet that provides a magnetic field configured to act on the emitted electrons, in at least part of the ion source chamber, in misalignment with the electric field.