[MIS12-P09] Comparison of element profiles obtained from Itrax-XRF core scanner in evaluating data quality among laboratories used by geological reference material.
Keywords:Itrax-XRF core scanner, data quality, geological reference material
The reference materials were firstly filled in 2.2×2.2 cm sample cube and covered by a thickness of 1.4 μm PET film. These samples were measured in 100, 30, 15, 5, 1 seconds of exposure times using Molybdenum (Mo) and Chromium (Cr) X-ray tubes at 0.2 mm intervals, respectively. All the XRF spectra were reevaluated by the Q-Spec software (Cox Analytical Systems, version 15.1) to obtain individual element peak area. The continuous 50 measurements in the central part of scanning were selected and averaged to avoid possible edge error. These results (Al, Si, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Ba, Pb) were further compared with the absolute concentrations of six reference materials and calculated the correlation coefficients (R2) with each exposure times and X-ray tubes.
Beside the results using Mo X-ray tube at AIST (failed to measure due to the machine failure), we compare our results with the data using first generation XRF detector in National Taiwan University (NTU, CS-16 in 2009) that reported by Huang et al. (2016). The correlation coefficients of Si, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Rb and Ba show high (R2>0.90) among all the laboratories in all machine setting, while Al shows low (R2<0.80). Therefore, we confirm that (1) the influence of different exposure times is insignificant for the accuracy of the scanning results; (2) Al is difficult to measure by Itrax due to its low detectability, even advanced XRF detectors in CMCR and AIST were used. More detailed discussion will be made once we obtain the Mo tube data of AIST.