Harvesting krypton isotopes from the off-gas of an irradiated water target to generate 76Br and 77Br

• Published in: Scientific reports 2022-01, Vol.12 (1)
• Main Authors: Clause, Hannah K., Domnanich, Katharina A., Kleinfeldt, Chloe, Kalman, Morgan, Walker, Wesley, Vyas, Chirag, Abel, E. Paige, Severin, Gregory W.
• Format: Article
• Language: English
• Subjects: Science & Technology - Other Topics
• ISSN: 2045-2322; 2045-2322

A flowing-water target was irradiated with a 150 MeV/nucleon beam of78Kr at the National Superconducting Cyclotron Laboratory to produce77Kr and76Kr. Real-time gamma-imaging measurements revealed the mass transport of the krypton radioisotopes through the target-water processing, or “isotope harvesting”, system. The production rates were determined to be 2.7(1) × 10–4nuclei of76Kr and 1.18(6) × 10–2nuclei of77Kr formed per incident78Kr ion. Utilizing an off-gas processing line as part of the isotope harvesting system, a total of 7.2(1) MBq of76Kr and 19.1(6) MBq of77Kr were collected in cold traps. Through the decay, the daughter radionuclides76Br and77Br were generated and removed from the traps with an average efficiency of 77 ± 12%. Due to the differences in half-lives of76Kr and77Kr, it was possible to isolate a pure sample of76Br with 99.9% radionuclidic purity. The successful collection of krypton radioisotopes to generate76Br and77Br demonstrates the feasibility of gas-phase isotope harvesting from irradiated accelerator cooling-water. Larger-scale collections are planned for collecting by-product radionuclides from the Facility for Rare Isotope Beams.