SRXRF analysis with spatial resolution of dental calculus

This work presents elemental-composition studies of dental calculus by X-ra y fluorescence analysis using synchrotron radiation. The intrinsic characte ristics of synchrotron light allow for a semi-quantitative analysis with sp atial resolution. The experiments were carried out in the high-vacuum stati on of the XRF beamline at the Synchrotron Light National Laboratory (Campin as, Brazil). All the measurements were performed in conventional geometry ( 45 degrees + 45 degrees) and the micro-collimation was attained via a pair of orthogonal slits mounted in the beamline. In this way, pixels of 50 mu m x 50 mu m were obtained keeping a high flux of photons on the sample. Samples of human dental calculus were measured in different positions along their growing axis, in order to determine variations of the compositions i n the pattern of deposit. Intensity ratios of minor elements and traces wer e obtained, and linear profiles and surface distributions were determined. As a general summary, we can conclude that mu XRF experiments with spatial resolution on dental calculus are feasible with simple collimation and adeq uate positioning systems, keeping a high flux of photon. These results open interesting perspectives for the future station of the line, devoted to mu XRF, which will reach resolutions of the order of 10 mu m. (C) 2000 Elsevi er Science B.V. All rights reserved.