Apparatus for sorting diamonds

摘要

In order to identify specific objects such as diamonds 2 in gangue on a conveyor belt, a line across the conveyor belt is irradiated with X-rays so that wanted particles 2 luminesce, and the luminescence is detected using an optical system 5 and a photo-multiplier tube 6. The response of the photo-multiplier tube 6 is scanned so that the location from which the luminescence was omitted is determined from the position of the scan at the instant of detection. The arrangement is useful for sorting minerals, including diamond, which luminesce.