Application of transition edge sensor (TES) to micro-XRF-XAFS for the speciation of cesium in glassy material emitted by Fukushima Dai-ichi Nuclear Power Plant accident

Abstract

The CsMP particles (CsMP), which are concentrated particles of radioactive cesium (Cs) released from the Fukushima Daiichi Nuclear Power Plant accident, are important as a material that reflects the physicochemical state inside the nuclear reactor during the accident and as a host material for radioactive Cs after deposition in the environment, and many studies have been conducted. Electron microscopy, µ-XRF, and fluorescence XAFS are effective methods to determine the distribution and chemical state of Cs in CsMP. However, energy-dispersive methods such as semiconductor detectors (SDD; energy resolution: about 130 eV) to detect characteristic X-rays and fluorescent X-rays (XRF) are difficult to identify Cs because of the interference between L-rays of trace Cs and K-rays of Ca and Ti, which are the main components of Cs. Therefore, in this study, we investigated the chemical state and distribution state of Cs in Type-B particles by XAFS and µ-XRF-XAFS methods using a superconducting transition edge sensor (TES) detector.