Compact ion chamber based neutron detector

摘要

A directional neutron detector has an ion chamber formed in a dielectric material; a signal electrode and a ground electrode formed in the ion chamber; a neutron absorbing material filling the ion chamber; readout circuitry which is electrically coupled to the signal and ground electrodes; and a signal processor electrically coupled to the readout circuitry. The ion chamber has a pair of substantially planar electrode surfaces. The chamber pressure of the neutron absorbing material is selected such that the reaction particle ion trail length for neutrons absorbed by the neutron absorbing material is equal to or less than the distance between the electrode surfaces. The signal processor is adapted to determine a path angle for each absorbed neutron based on the rise time of the corresponding pulse in a time-varying detector signal.

主权项

1. A neutron detector with monolithically integrated readout circuitry, comprising:
a bonded semiconductor die including an etched substrate bonded to an active semiconductor substrate; an ion chamber formed in the etched substrate, the ion chamber having a pair of parallel, substantially planar surfaces; a first electrode formed on one said surface; a second electrode formed on the other said surface at an interelectrode separation distance from the first electrode; a material, filling the ion chamber, that reacts with neutrons to create ion trails; and readout circuitry formed in a portion of the active semiconductor substrate and electrically coupled to the first and second electrodes; wherein the interelectrode separation distance is no more than half an attenuation length for thermal neutrons in the ion-trail-creating material filling the ion chamber at a pressure of 100 atm at room temperature.