Investigation of the absorption and scattering behaviour of gamma radiation in fine grained hard coal and coal slurry due to the photo effect and Compton effect with regard to determining the ash and solid contents

In the context of the development of a fast measuring equipment for the continuous on-line determination of the ash content of fine-grained hard coal or the ash and solid contents of flotation products, the absorption and scattering ability of γ radiation due to the photo effect and Compton effect was simulated by model calculations. The composition of the coal and the adjacent rock and the proportion of water were varied within wide limits, in order to characterize interference effects such as iron and water content. Good agreement was found with experimental results, so that the different methods of measurement can be described very well phenomenologically, so that a deeper understanding of the method of operation is made possible by the usual backscattering method for a quick determination of the ash content. The most important result is that it is not the Compton effect, but the photo effect which decisively influences the result. Therefore, the backscattering method, which is based on the backscattering of Am and the transmission method, where the absorption of Am radiation is determined and in addition Cs measuring section is required for density compensation, are based on the same physical principle. (orig./HP)