Desenvolvimento e caracterização de um sistema automatizado portátil de fluorescência de raios X por reflexão total

Abstract

This work presents the development and characterization of a portable automated total reflection X ray fluorescence system (TXRF). The system presents a compact arrangement consisting of a 50 kV X-ray tube with molybdenum anode and a Si-PIN detector, quartz optical flat, lucite monochromator, linear positioners and a goniometer driven by stepper motors controlled through software in programming Arduino. The system was subjected to verification tests of the beam geometric center, angular variation, repeatability, sensitivity curve, limit of detection (LD), precision and accuracy. The system had an application in the analysis of bovine milk samples collected in the city of Bauru, São Paulo. In the repeatability test, the system presented a variation coefficient equal to 3.5%. The precision and accuracy were approximately 17% and 7%, respectively. The LD observed was in the range from 34 g.g -1 to 0.08 g.g -1 (15 ≤ Z ≤ 37). In the analysis of bovine milk samples, the following elements were detected: P, S, K, Ca, Mn, Fe, Ni, Cu, Zn, Rb and Sr. Comparing the quantitative results with the TXRF system, it can be concluded which data are compatible with the technical analyzes used for bovine milk analysis. The system proved to be efficient, proving that it is possible to produce Xray fluorescence with a high-tech, low-cost system using a low-power X-ray tube and a compact Si-PIN detector.