Aqueous and Solid Phase Isotope Harvesting at FRIB

At the Facility for Rare Isotope Beams (FRIB), exotic secondary beams are produced through the fragmentation of a high-power primary beam. In this process, only a small fraction of the generated beam products are utilized for nuclear physics research. The co-produced fragments are intercepted by accelerator components, while the unreacted primary beam is stopped in a water-cooled beam dump. These accumulated radionuclides represent a valuable resource for isotope harvesting.

This talk will first give an overview of the isotope harvesting process, focusing on ⁶²Zn collected from a stopped ⁷⁸Kr beam. The ⁶²Zn decays to the short-lived ⁶²Cu (t_1/2= 9.7 min) and currently, both find collective application in nuclear medicine for the ⁶²Zn/⁶²Cu PET generator. We developed and tested purification methods to isolate ⁶²Zn, started the chemistry development to set up a ⁶²Zn/⁶²Cu generator, and successfully radiolabeled ⁶²Cu in a recent experiment.

In addition, isotope collection from the solid phase is another possible isotope harvesting mode. We started to explore the radioisotopes ¹⁸⁹Pt and ¹⁹⁷Pt, which are relevant for nuclear medicine applications such as radio-cisplatin. A separation process was established to extract Pt from the collector matrix and co-implanted impurities. We are currently preparing for the beam time experiment.

Isotope harvesting, however, is generally non-selective towards producing a particular isotope, and often direct harvesting efforts do not yield radioisotopically pure samples. To expand access to pure radioisotopes, the implementation of a mass-separation step is being pursued. FRIB’s existing infrastructure includes a mass analyzer, enabling a prototype mass separator. I will present results from a mass-separation experiment using ⁶¹Ni and an outlook towards this prospective extension of the existing isotope harvesting program.