Quantitative gas-phase separation of carrier-free thallium radioisotopes from proton-irradiated nat HgO

Carrier-free $_{}^{202}\text{Tl}$ was thermally separated from proton-irradiated $_{}^{\text{nat}}\text{HgO}$ . Pressed $_{}^{\text{nat}}\text{HgO}$ targets were irradiated with $\approx 26\text{MeV}$ protons at the IP2 beamline of the high-intensity proton accelerator facility at the Paul Scherrer Institute. The well-known thermal decomposition of $\text{HgO}$ at $>470_{}^{\circ }$ C and the strong adsorption of $\text{Tl}$ on a $\text{Ta}$ surface allowed for a simple and quantitative gas-phase separation of carrier-free $\text{Tl}$ from bulk amounts of $\text{HgO}$ target material between 550 and $670_{}^{\circ }$ °C. The separation efficiency was verified by $\gamma$ -spectroscopy via the main $\gamma$ -emissions of $_{}^{202}\text{Tl}$ and co-produced $_{}^{203}\text{Hg}$ . This method generally provides a fast and reliable preparation of carrier-free, neutron-deficient $\text{Tl}$ radioisotopes (e.g., medically relevant $_{}^{201}\text{Tl}$ ) from a proton-irradiated $_{}^{\text{nat}}\text{HgO}$ matrix.