From the accelerated heavy ions at the NSCL (National Superconducting Cyclotron Laboratory) only a small fraction is used for the production of secondary beams. Replacing a conventional solid beam blocker with a flowing water target creates a possibility to collect a variety of exotic radionuclides in a synergistic manner with other experiments. The radioisotopes 77Kr and 76Kr represent the main reaction products of a 78Kr beam stopped in water, however, in a side reaction the formation of 62Zn (t1/2= 9.2 h) occurs at a production rate of 9.08(30)*10-5 atoms per incoming 78Kr. The positron emitting 62Zn decays to the short-lived 62Cu (t1/2= 9.7 min, Iβ+= 100%) and currently both find collective application in nuclear medicine for the 62Zn/62Cu PET generator. Additionally, zinc functions as essential nutrient in many biological systems which makes this heavy metal also interesting for plant uptake studies. In this work we present the feasibility of collecting 7.6 (29)–11.1 (41) μCi 62Zn in the background of a 76,77Kr collection, both created by an impinging 78Kr beam (150 MeV/u, max. 2.2–3.7 pnA, 14.9–25.1 W) on an aqueous matrix. The produced radionuclides were captured on a set of cation and anion columns, whereby 62Zn exclusively exists as cation under the prevailing neutral pH conditions. A kinetic model was used to describe the column adsorption behavior of the generated radioactive species and additionally allowed estimation of the formation rates of twenty other radionuclides. With the subsequent purification method, based on anion exchange, 62Zn was separated from accompanying radioactive and stable nuclides. The radiogenerator principle was demonstrated by the successful isolation of pure 62Cu. Secondly, the obtained 62Zn was utilized in a proof-of-principle uptake and imaging experiment in a hydroponic garden cress culture.

Harvesting 62Zn from an aqueous cocktail at the NSCL

ACS Spring Meeting 2021

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