A nondestructive inspection apparatus makes a neutron beam incident on an inspection target, detects a specific gamma ray deriving from a target component in the inspection target, among gamma rays generated by the neutron beam, and determines a depth at which the target component exists, based on a result of the detecting. The nondestructive inspection apparatus includes a neutron source that emits a neutron beam to a surface of the inspection target, a gamma ray detection device that detects, as detection intensities, intensities of a plurality of types of specific gamma rays whose energy differs from each other, and a ratio calculation unit that determines a ratio between the detection intensities of a plurality of types of the specific gamma rays.

Provided herein are neutron-based detection systems and methods that provide, for example, high throughput analysis of elemental analysis of scrap materials. Such systems and methods find use for the commercial-scale evaluation of bulk process materials where hazardous or otherwise undesirable materials or high value materials may be interspersed with the primary process material. In certain embodiments, the system is used to detect and potentially remove unexploded ordinance (UXO) from a conveyor of demilitarized shell casings being recycled by detecting the presence of nitrogen and other elements present in the UXO. In other embodiments, the system detects and removes unwanted or highly valuable materials from a stream of scrap material.

Methods and systems for non-intrusively detecting existence of fissile materials by measuring energetic prompt neutrons. The unique nature of the prompt neutron energy spectrum from photo-fission arising from emission of neutrons from almost fully accelerated fragments is used to unambiguously identify fissile material. Angular distribution of prompt neutrons from photo-fission and energy distribution correlated to neutron angle relative to the photon beam are used to distinguish odd-even from even-even nuclei undergoing photo-fission. Independence of the neutron yield curve (yield as a function of electron beam energy or photon energy) on neutron energy is used to distinguish photo-fission from other processes such as (, n). Different beam geometries detect localized samples of fissile material and fissile materials dispersed as small fragments or thin sheets over broad regions. These signals from photo-fission are unique, allowing detection of any material in the actinide region of the nuclear periodic table.

A nondestructive inspection apparatus makes a neutron beam incident on an inspection target, detects a specific gamma ray deriving from a target component in the inspection target, among gamma rays generated by the neutron beam, and determines a depth at which the target component exists, based on a result of the detecting. The nondestructive inspection apparatus includes a neutron source that emits a neutron beam to a surface of the inspection target, a gamma ray detection device that detects, as detection intensities, intensities of a plurality of types of specific gamma rays whose energy differs from each other, and a ratio calculation unit that determines a ratio between the detection intensities of a plurality of types of the specific gamma rays.