Method and apparatus for analyzing ore by means of gamma radiation

An apparatus for analysing a piece of ore by means of gamma radiation, for the purpose of sorting, comprising two sources of gamma radiation, each operating at a different energy level, the sources of radiation being fitted to irradiate the piece substantially simultaneously and their levels of energy being selected so that in the scatter of the radiation the Compton effect is predominant at one energy level and the Compton effect and the photoelectric effect compete with each other at the other energy level,

• a detector for detecting scatter produced by the radiations, said detector being situated so that it receives substantially only radiation scattered from the piece and measuring means connected to the detector for comparing with each other intensities of the scatters produced by the two sources of radiation.

A method for analysing pieces of ore for the purpose of sorting, comprising

• irradiating the pieces individually by means of two similar pairs of gamma radiation sources, each of said pairs of sources comprising sources operating at different energy levels, the energy levels of the sources having been selected so that, as to scattering, in one the Compton effect is predominant and in the other the Compton effect and the photoelectric effect compete with each other, the photoelectric effect being strongly dependent on the ordinal number of each element present in the ore;
• and
• detecting by means of at least one detector positioned symmetrically between the pairs of sources the intensities of the scatter produced from said piece by said two sources of radiation of both pairs of sources and comparing the detected intensities with each other in order to determine the proportion of heavy elements present in the piece.

An apparatus for analysing a piece of ore by means of gamma radiation, for the purpose of sorting, comprising two similar pairs of sources of gamma radiation, each of said pairs of sources comprising two sources operating at different energy levels, the sources of radiation being fitted to irradiate the piece simultaneously and their levels of energy being selected so that in the scatter of the radiation the Compton effect is predominant at one energy level and the Compton effect and the photoelectric effect compete with each other at the other energy level,

• a detector positioned symmetrically between said pairs of sources for detecting scatter produced by the radiations, said detector being situated so that it receives substantially only radiation scattered from the piece and measuring means connected to the detector for comparing with each other intensities of the scatters produced by the two sources of radiation of both pairs of sources.