Analysis of uranium in environmental samples by micro X-ray fluorescence spectroscopy using transition edge sensors

Yomogida, Takumi   ; Yamada, Shinya*; Ichinohe, Yuto*; Sato, Toshiki*; Hayakawa, Ryota*; Okada, Shinji*; Toyama, Yuichi*; Hashimoto, Tadashi   ; Noda, Hirofumi*; Isobe, Tadaaki*; Okumura, Takuma*; Takatori, Sayuri*; Hiraki, Takahiro*; Tatsuno, Hideyuki*; Sekizawa, Oki*; Nitta, Kiyofumi*; Kurihara, Yuichi*; Uruga, Tomoya*; Kitatsuji, Yoshihiro  ; Takahashi, Yoshio*

Biotite is known as a host phase that retains uranium (U) in uranium deposits at Ningyo-Toge and Tono, and it is expected that the distribution of U in biotite will provide insight into the concentration and long-term immobilization of U. However, biotite contains rubidium (Rb), which interferes with X-ray fluorescence analysis, making it difficult to accurately determine the distribution of U-Rb in biotite by measurement using a conventional solid state detector (SSD). In this study, we developed a method to use a transition edge sensor (TES) as a detector in microbeam X-ray fluorescence analysis, which enables us to detect X-ray fluorescence with an energy resolution of about 20 eV and to obtain a Rb K line at 13.373 keV and a U L line at 13.612 keV can be completely separated. Therefore,the developed method enables us to accurately determine the distribution of U-Rb in biotite.