Production and purification of molecular ²²⁵Ac at CERN-ISOLDE

The radioactive nuclide ²²⁵Ac is one of the few promising candidates for cancer treatment by targeted- $$ -therapy, but worldwide production of ²²⁵Ac faces significant limitations. In this work, the Isotope Separation On-Line method was used to produce actinium by irradiating targets made of uranium carbide and thorium carbide with 1.4-GeV protons. Actinium fluoride molecules were formed, ionized through electron impact, then extracted and mass-separated as a beam of molecular ions. The composition of the mass-selected ion beam was verified using time-of-flight mass spectrometry, $$ - and $$ -ray decay spectrometry. Extracted quantities of $$ particles per $$ C of incident protons were $$ from a uranium carbide target and $$ for a thorium carbide target. Using a magnetic mass separator, the long-lived contamination ²²⁷ Ac is suppressed to $$ (95% confidence interval) with respect to ²²⁵Ac by activity. Measured rates scale to collections of 108 kBq $$ A $$ h $$ of directly produced $$ .