We propose that132Cs (Eγ = 668 keV and T1/2 = 6.5 d) can replace137Cs (Eγ = 662 keV and T1/2 = 30 y) as a new environmental tracer of cesium. The alternative tracer,132Cs, can potentially reveal the short-time dynamics in an environment, which are considered to dominate radioactive cesium absorption after nuclear accidents. We first investigate the production yield and radioactive purity of132Cs in a production experiment at the Cyclotron and Radioisotope Center of Tohoku University. The132Cs was produced via the133Cs(n,2n) reaction with neutrons generated by bombarding accelerated deuterons onto a 4 mm-thick neutron converter made of carbon. The generated neutrons were then irradiated onto a Cs2CO3 sample. The experiment yielded 102.2 kBq/g of132Cs, sufficient for tracing environmental cesium. The radioactive purity reached 98%, indicating negligible amounts of by-products. Next, a132Cs tracer experiment was performed on three different soil samples: an andosol soil, a haplic fluvisol soil, and a gleyic fluvisol soil. This feasibility study confirmed that the new tracer can measure soil cesium distributions as adequately as the137Cs tracer. Thus, we conclude that132Cs is a promising alternative environmental tracer of 137 Cs.
- Accelerator-based neutrons
- Environmental tracer
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Surfaces, Coatings and Films
- Management, Monitoring, Policy and Law