Methods and systems for time-of-flight neutron interrogation for material discrimination

摘要

The present specification discloses a system for inspection of a suspect area in an object, said suspect area being in the range of a few tens of centimeters, the system comprising:a d-T neutron generator, that produces neutrons and corresponding alpha particles;a neutron beam collimator to direct the neutrons at the suspect area, wherein said collimator is shielded using layers comprising at least one of borated polyethylene, tungsten, steel, copper and lead to reduce neutron leakage and gamma rays produced in the collimator;an alpha-particle detector placed 180-degrees relative to the suspect area to detect alpha particles and determine the time of generation of neutrons, wherein the alpha-particle detector is collimated to substantially the same angular opening as the neutron beam collimator;gamma-ray detectors to detect gamma rays produced after the interaction of neutrons with the suspect area, wherein said gamma ray detectors are shielded to prevent thermal and epi-thermal capture; anda processing unit to determine the elemental composition of the suspect area as a function of depth based on the time of generation of the neutrons and the time spectrum of the gamma rays produced