An application of micro X-ray fluorescence computed tomography for the determination of three-dimensional elemental distribution in a single hair strand

Three-dimensional imaging of trace elements in a single hair strand was achieved by a micro X-ray fluorescence computed tomography (mu XRF-CT) using synchrotron radiation. A simple rotational mechanism was attached to a two-dimensional XRF imaging system and a wide range of longitudinal scans was realized. The experimental determination of centroid of projections helped to maintain the spatial resolution around 2 mu m that was determined by the beam size. Determination of trace element concentration in a single hair strand was realized by combining measurements of both scattered X-ray and XRF intensities, and longitudinal changes in concentration were observed. Cross-sectional distribution of Br, Zn, Fe and Cu were obtained at the positions of interest after the longitudinal scan, and changes in distribution forms were observed.