Abstract: An apparatus, method and computer program product for determining a concentration of a high-Z material in a material sample. The method comprises steps of: receiving a material sample and subjecting the material sample to a first sensor device that is substantially ash insensitive for generating a first sensor response signal, and a second sensor device that is sensitive to presence of high-Z material and generating a second sensor response signal. Both the first and second sensor response signals from the first and second sensor devices are processed simultaneously to extract a weight of the high-Z material additive. The weight of the high-Z material additive is determined in a single scan of the material sample.