Correction of X-ray tube aging effects and quantitative estimation of elemental composition using the ITRAX XRF core scanner: a case study of Japan Sea sediments

Abstract

The XRF core scanner, which facilitates non-destructive, high-speed, and high spatial resolution measurements, has recently been extensively used to measure element variability in sediments. Although identifying the precision of the measurement and concentration of the elements in the sample is essential to elucidating the variations recorded in the sediments, the element peak area count ratios are most commonly used to report the results of XRF core scanners in many previous studies, and element concentration is not discussed. This is mainly because quantitative calibration of element concentration necessitates numerous additional analyses of discrete samples. Because XRF core scanner measurements are often conducted before discrete sample analysis, if approximate element concentrations in the sediment can be estimated from XRF core scanner data just after measurement, sampling intervals should be determined for further analysis.In this study, we developed a new database on the aging of X-ray tubes, and propose a method for estimating element concentrations in the wet sediments from XRF core scanner measurement without any additional measurement. The ITRAX XRF core scanner at Kochi University, the first ITRAX installed in Japan in 2014, was used in this study. Mo X-ray tubes were used at 30 kV, 55 mA with XRF exposure time of 10 s or 32 s. First, the aging effect of the X-ray tube was monitored and its correction method was proposed. Subsequently, the precision of the ITRAX XRF measurements was evaluated and the relationship between the element peak area count by ITRAX and element concentration was analyzed. Finally, we propose a new method for applying these databases constructed in this study to any results measured by ITRAX XRF core scanner at Kochi University. Using this method, anyone can estimate approximate element composition of the sediment from their XRF core scanner data obtained at Kochi University without any additional measurement. This method even enables estimation of element concentrations of sediments just after the ITRAX measurement.