Method of and apparatus for determining the nature of transported material

摘要

A coal/stone mixture transported on a conveyor is investigated by subjecting it to two radiation beams of differing energies. In a preferred embodiment, the higher energy radiation is collimated into a pencil beam and the lower energy radiation into a fan beam. Detector shielding prevents substantial interference of close-to-surface reactions within the detector deriving from the higher energy beam with detection of the lower energy beam.