Non-destructive evaluation of thickness of material plates through Compton back-scattering technique using Si(Li) detector

This study aims to develop the system for the non-destructive evaluation of the thickness of material plates based on the Compton back-scattering technique using a Si(Li) detector and 241Am radioactive sources. The calibration curve is constructed based on the areas under the Compton scattering peak obtained from the measurements of reference samples. This calibration curve is used to determine the saturation thickness, the maximum measurable thickness (MMT) with the desired accuracy, and the unknown thickness of a sample. To validate the reliability of the system, we have performed thickness measurements for seventeen aluminum samples with different thicknesses in the range of 4.40–21.07 mm. The samples are measured seven times, except for two samples with thicknesses of 11.52 mm and 14.98 mm up to twenty times. The Pearson's correlation coefficient between the reference and measured thicknesses presented a strong positive correlation. The average relative deviation between the reference and measured thicknesses is less than 1%.