Multiple scattering corrections for density profile unfolding from Compton scattering signals in reflection geometry

Recently, a mathematical procedure was reported to unfold the density profile of wood panels from the measurement of the integrated scatter signal that contains prevalently the Compton component. An experimental device (patent claimed) has been used for these measurements. It uses reflection geometry to maximize the Compton signal. The influence of multiple scattering (MS) is not negligible as has been estimated using the Monte Carlo code MCSHAPE3D. However, Monte Carlo computations are time consuming. Therefore, in practice, the MS correction is computed off-line for few thicknesses of the specimen assuming known composition and density. Then, an original 2D interpolation algorithm is used to apply the MS correction to an arbitrary thickness scatterer, in order to improve the precision of the unfolded density profile in real time at the production line. The MS corrected density profiles are in good agreement with direct measurements performed with other means.