Production of Sulfur-35 by the Cation Exchange Process

Sulfur-35 is the most commonly used radioactive isotope of sulfur, and it is a cosmogenic isotope that has a half life of 87 days. The short half life of 35S allows it to be used to examine the influence of recent (∼1yr) precipitation. The presence, or subsequent absence, of 35S indicates the source of at least part of the water is recent precipitation, and there is a flowpath which delivers this water to the sampled location. 35S is a conservative tracer, and acts as sulfate as it flows through the system. Sulfur-35 is usually produced by neutron irradiation on potassium chloride, utilizing the 35Cl(n,p)35S reaction. Although the 34S(n, γ)35S reaction can also be utilized, it produces a product of low specific activity and is not practical. In this study, technique to produce carrier-free sulfur-35 from neutron irradiated potassium chloride was developed. For the post-irradiation process, the cation exchange method based on the selective adsorption of phosphate on Fe+3-cation exchange resin was adopted