Establishment of measurement methods for ¹³⁵Cs

Abstract

Cs collection methods from environmental water (seawater) with less interference isotopes for the determination of ¹³⁵Cs by mass spectrometry has been developed in addition to attempt Cs isotope measurement by AMS. Adsorption/desorption experiments of ¹³⁷Cs and ¹³³Ba were using copper-substituted Prussian blue nonwoven fabric (PB). For AMS measurements， Cs negative ion beam extractions from some reagents were attempted using both Rb ion source and conventional Cs ion source. In the 24-hour adsorption experiments with 1 L of seawater, the adsorption rates of ¹³⁷Cs were 39% for PB sizes of 4 cm² and 85% for PB sizes of 25 cm². Adsorption rates of ¹³³Ba were less than 5% for all experiments. In the desorption experiments, only 40% of Cs was desorbed by 30% HNO₃, but more than 95% of Cs was desorbed by 35% HCl. As a result of the AMS experiments, CsS^- and CsF₂^- were observed in Cs beam that were sputtered by Cs and Rb.