Toward new frontiers : Encounter and synergy of state-of-the-art astronomical detectors and exotic quantum beams

Program A01-4	Advanced Earth and Planetary Sciences developed by application of TES to XAFS studies
Principal Investigator	TAKAHASHI, Yoshio (The University of Tokyo)

High energy resolution fluorescence XAFS for the speciation of trace elements in geochemical and environmental samples using transition-edge sensor (TES) detector

Speciation of trace elements in environment is essential for better understanding of their behaviors in environment. For this purpose, X-ray absorption fine structure spectroscopy (XAFS) analysis in fluorescence mode using intensity of X-ray fluorescence (XRF) to know the degree of X-ray absorption is one of most useful methods, but interference on the XRF signal of each trace element by those from background elements is a severe problem to selectively obtain the signal from trace elements. Transition-edge sensor (TES) detector is one of most attractive energy-dispersive detectors to measure XRF separately from other interference signals from coexistent elements and scattering X-rays based on its high energy resolution detection of X-rays (e.g., 5 eV at 6 keV), though the resolution is somewhat lower than that of wavelength dispersive method using Bragg-type crystal analyzer system with 1–2 eV energy resolution. We here study potentials of TES for various X-ray spectroscopies including XAFS, which consists of XANES (X-ray absorption near-edge structure) and EXAFS (extended X-ray absorption fine structure), and X-ray emission (XES) spectroscopy based on the high energy resolution. Three main applications (Fig. 1) will be tested as follows:

(1) High-sensitive measurement of XAFS (mainly XANES) in the presence of other interference elements for trace elements such as rare earth elements (REE) and platinum (Pt) in weathered granite and marine ferromanganese oxides, respectively, which are important as potential metal resources of REE and Pt.

(2) Applications of TES for X-ray microscopy, in which elemental mapping by the detection of XRF during scanning of sample in micrometer or submicrometer scale. High separation ability of TES enables us to obtain mapping of each element without any interferences from other elements. Moreover, possible application of shift of XES during the mapping will be conducted to know whether the method can reflect variation of chemical species in the sample or not.

(3) On the other hand, normal XANES is not very informative in terms of chemical state analysis of various elements in the samples. However, higher energy resolution detection of fluorescence X-ray than the degree of lifetime broadening enables us to measure XANES itself by better energy resolution, which is known as high energy resolution fluorescence detection (HERFD) XANES. The HERFD-XANES has more information on electronic state of each element given by the method, by which we can extract chemical information to the maximum degree possible. Thus, we here try to measure HERFD-XANES for the speciation of cesium and barium adsorbed within the interlayer of phyllosilicates.


Fig. 1. Development of XAFS and XRF spectroscopies using high energy resolution power of TES.

Members

Reference Materials

• H. -B. Qin, S. Yang, M. Tanaka, K. Sanematsu, C. Arcilla, Y. Takahashi, “Scandium immobilization by goethite: Surface adsorption versus structural incorporation,” Geochim. Cosmochim. Acta 294, 255–272 (2021).
• S. Yamada, Y. Ichinohe, H. Tatsuno, R. Hayakawa, H. Suda, T. Ohashi, Y. Ishisaki, T. Uruga, O. Sekizawa, K. Nitta, Y. Takahashi, T. Itai, H. Suga, M. Nagasawa, M. Tanaka, M. Kurisu, T. Hashimoto, D. Bennett, E. Denison, W.B. Doriese, M. Durkin, J. Fowler, G. O'Neil, K. Morgan, D. Schmidt, D. Swetz, J. Ullom, L. Vale, S. Okada, T. Okumura, T. Azuma, T. Tamagawa, T. Isobe, S. Kohjiro, H. Noda, K. Tanaka, A. Taguchi, Y. Imai, K. Sato, T. Hayashi, T. Kashiwabara, K. Sakata, “Broadband high-energy resolution hard x-ray spectroscopy using transition edge sensors at SPring-8,” Rev. Sci. Instrum. 92(1), 013103 (2021).
• H. Miura, Y. Kurihara, M. Yamamoto, A. Sakaguchi, N. Yamaguchi, O. Sekizawa, K. Nitta, S. Higaki, D. Tsumune, T. Itai, Y. Takahashi, “Characterization of two types of cesium-bearing microparticles emitted from the Fukushima accident via multiple synchrotron radiation analyses,” Sci. Rep. 10(1), 11421 (2020).
• G. -I. Uramoto, Y. Morono, N. Tomioka, S. Wakaki, R. Nakada, R. Wagai, K. Uesugi, A. Takeuchi, M. Hoshino, Y. Suzuki, F. Shiraishi, S. Mitsunobu, H. Suga, Y. Takeichi, Y. Takahashi, F. Inagaki, “Significant contribution of subseafloor microparticles to the global manganese budget,” Nat. Commun. 10(1), 400 (2019).
• Y. Takahashi, Q. Fan, H. Suga, K. Tanaka, A. Sakaguchi, Y. Takeichi, K. Ono, K. Mase, K. Kato, V. V. Kanivets, “Comparison of solid-water partitions of radiocesium in river waters in Fukushima and Chernobyl Areas,” Sci. Rep. 7(1), 12407 (2017).