Coal analysis

Abstract

An analysis method and system for analyzing coal or other material causes the material to be bombarded with neutrons from a source, and this generates gamma rays from the material which are detected by a detector. The detector has scintillators which generate light when a gamma ray is detected, the light being detected by photomultipliers. Each gamma ray generates two other gamma rays, which may both be wholly absorbed in one or the other scintillator, or one absorbed in one scintillator and one in the other. By analyzing these events, the spectrum of gamma rays may be obtained, giving the composition of the material. One preferred detector has an array of scintillators and coincident gamma ray detection events in three adjacent scintillators detected by detecting if a primary scintillator detector event is coincident with detection events in the other two scintillators. For each detection event, one of the scintillators is selected as a primary scintillator, and two other scintillators, on opposite sides of the primary scintillator, are selected. The detection event in the selected primary scintillator is compared with the detection events in the two other selected scintillators to determine coincidence. In another embodiment, two gamma detectors of differing properties are used, with each detector having a plurality of scintillators. Coincident events are detected in one detector and anticoincident events in the other.