Rapid separation of gallium from zinc targets by thermal diffusion

We present a simple, non-destructive and rapid method to separate radioactive gallium isotopes from a zinc target. Irradiated target foils were heated up to 400°C, that is close to the melting point of zinc. At this temperature the gallium isotopes became movable in the zinc matrix and were concentrated on the surface of the target. By dipping the foils into a weak acid, more than 60% of the radioactivity was etched off the target (thickness 100 μm) and with less than 0.5% loss of the target material. The total separation time was less than 30 min. The method can be applied with enriched zinc targets and low energy proton reactions and may, e.g. produce high amounts of positron emitting gallium isotopes (66Ga and 68Ga) by the use of accelerators available at PET-centers.