Study of zinc coating thickness gauge by Monte Carlo simulation

This paper introduces how to utilize the Monte Carlo N-Particle Transport Code (MCNP) in calculating the thickness of zinc coating which distributed homogeneously in an analyzed specimen. Experiments were performed on the specimens that made of 2 mm thickness steel substrates which covered by intermediate thickness (40-175 gm(-2)) zinc layer, with the purpose of analyzing the x-ray fluorescence spectra and comparing the changes of zinc fluorescence detection efficiency under different energy monochrome photons or different detector distance. The results show that when the energy of monochrome photons is equal to 10 keV as well as the distance of detector is equal to 4 cm, the fluorescence of zinc K alpha has a very good linear relationship with the thickness of zinc coating. It indicates that the MCNP code can be applied for simulating the galvanizing thickness gauge. In addition, under the same other conditions, the experimental results were not affected by different incident spot sizes (0.01-1cm).