METHOD OF MONITORING A HIDDEN COAL-ROCK INTERFACE AND A TRANSMITTER FOR PERFORMING THIS METHOD

摘要

The method of monitoring a hidden coal-rock interface includes irradiating the medium being monitoring from a gamma-ray source and registering by a detector the intensity of backward scattered radiation at a spacing from the surface of the monitoring medium and at a spacing from the radiation source. There are formed at the detector two zones of reception or backward scattered radiation, differently spaced from the source, so that the intensity of backward scattered radiation received by the zone closer to the source diminishes, and the intensity of backward scattered radiation received by the zone more remote from the source grows with a growing spacing of the detector from the monitored medium. The intensities of backward scattered radiation at the two zones are summed up to obtain the summary intensity invariant with respect to a varying spacing of the detector from the monitored medium. The transmitter for performing the method comprises a housing acommodating a gamma-ray source and a detector of backward scattered radiation, enclosed in a screen having made therein ports differently spaced from the source. The area of the port more remote from the source is greater than the area of the less remote port, and the spacing of the source from the detector does not exceed a preset maximum value of the spacing of the detector from the monitoring medium.