XRF mapping for identifying inhomogeneity of elemental distribution in multi-layer flexible films for attenuating X-rays

X-ray fluorescence (XRF) analysis is a widespread and preferred method for a variety of analytical applications. Among other aspects, it is an excellent method for identifying inhomogeneities in elemental distribution due to its non-invasiveness and non-destructiveness. However, the fact that it uses relatively low-energy X-rays brings some limitations and problems in interpreting the measurement results, especially if objects with multi-layer thicker films are investigated. In this paper, an XRF mapping method based on a heavy metal tungsten target is presented to handle this problem. Using the principle of material genome engineering, 50 wt% Bi 2 O 3 -Sm 2 O 3 -Er 2 O 3 /natural rubber (NR) films for attenuating X-rays are prepared by a latex impregnation method. The combination of Bi 2 O 3 , Sm 2 O 3 and Er 2 O 3 can achieve the best protection effect on 20-100 keV wide-spectrum X-rays and also make up for the weak absorption region of a single material. Macroscopic (XRF mapping) and microscopic (submicron computed tomography (CT) and energy-dispersive spectrometer (EDS)) methods show that the filler is well dispersed in the NR. The shielding properties of Bi 2 O 3 -Sm 2 O 3 -Er 2 O 3 /NR flexible film show that it can be used in the X-ray protection field. The importance of the XRF mapping method is related to the need to identify the distribution of the chemical elements in large surface areas of objects by a non-destructive method compared to an EDS.