A new Monte Carlo program for computing low-energy gamma- and x-ray propagation in an axially-symmetric XRF system

Annular XRF systems, using backscattering geometry, have advantages of convenience of use, but it is difficult to predict their sensitivity to concentrations of heavy metals at different depths, or the contribution of scattered radiation to the background. A Monte Carlo program has therefore been developed to carry out calculation of this type. Several variance-reduction techniques are included. Preliminary results for the detection of platinum are given.