5:15 PM - 7:15 PM
[MIS23-P06] Quantitativeness of sediment core surface micro XRF mapping under atmospheric condition using M6 JETSTREAM
Keywords:micro XRF mapping, sediments, core, quantitativity, the Japan Sea, M6 JETSTREAM
Non-destructive, high-resolution measurement of sediment cores are useful to reveal sediment feature which reflect climatic or oceanographic changes. Non-destructive feature is especially important for valuable sediment core samples such as obtained by international ocean drilling program. Although non-destructive, high-resolution micro XRF mapping analysis is a useful method to reveal fine scale sediment feature, such analysis usually applicable to limited sized samples (up to ~30 cm) because samples are analyzed in the vacuum chamber. Therefore, this method was usually not applicable to 1.5 m long legacy cores obtained by international ocean drilling program.
In this study, we utilize M6 JETSTREAM provided by Bruker Corporation, which could conduct non-destructive measurement for 80 cm × 60 cm wide area, with high-resolution less than mm scale. This equipment could measure 1.5 m long archive half cores directly and could make high-resolution element maps. However, since analysis are usually conducted under atmosphere, quantitative analysis of measurement results is usually difficult.
In this study, we measured the Japan Sea sediment standard samples (Dunlea et al., 2020) under various measurement settings to check quantitativeness of M6 JETSTREAM analysis. We changed measurement settings such as “measurement time”, “aperture setting”, “X-ray tube voltage and current” “distance between sample and detector”, “on/off of He flush”, and calculated peak area counts of 25 elements (Mg, Al, Si, S, Cl, Ar, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, Zr, Rh, Ba) using attached software. Then, we compared these results to reveal difference caused by each measurement settings.
As a results, some measurement settings affected peak area counts of all elements in the same way, and other condition affected differently for lighter elements and heavier elements. In addition, among 17 elements which concentration in the Japan Sea sediment standard sample are known, high correlation calibration curves were obtained for four elements.
These calibration curves and the different results between various analytical settings obtained in this study enables us to roughly estimate elemental composition of unknown samples soon after the measurement. The database provided by this study could be used by other researchers to interpret their analytical results obtained by M6 JETSTREAM.
In this study, we utilize M6 JETSTREAM provided by Bruker Corporation, which could conduct non-destructive measurement for 80 cm × 60 cm wide area, with high-resolution less than mm scale. This equipment could measure 1.5 m long archive half cores directly and could make high-resolution element maps. However, since analysis are usually conducted under atmosphere, quantitative analysis of measurement results is usually difficult.
In this study, we measured the Japan Sea sediment standard samples (Dunlea et al., 2020) under various measurement settings to check quantitativeness of M6 JETSTREAM analysis. We changed measurement settings such as “measurement time”, “aperture setting”, “X-ray tube voltage and current” “distance between sample and detector”, “on/off of He flush”, and calculated peak area counts of 25 elements (Mg, Al, Si, S, Cl, Ar, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, As, Br, Rb, Sr, Y, Zr, Rh, Ba) using attached software. Then, we compared these results to reveal difference caused by each measurement settings.
As a results, some measurement settings affected peak area counts of all elements in the same way, and other condition affected differently for lighter elements and heavier elements. In addition, among 17 elements which concentration in the Japan Sea sediment standard sample are known, high correlation calibration curves were obtained for four elements.
These calibration curves and the different results between various analytical settings obtained in this study enables us to roughly estimate elemental composition of unknown samples soon after the measurement. The database provided by this study could be used by other researchers to interpret their analytical results obtained by M6 JETSTREAM.