Production and purification of molecular ²²⁵Ac at CERN-ISOLDE
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-α-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, α- and γ-ray decay spectrometry. Extracted quantities of ²²⁵Ac¹⁹F₂⁺ particles per μC of incident protons were 3.9(3)×10⁷ from a uranium carbide target and 4.3(4)×10⁷ for a thorium carbide target. Using a magnetic mass separator, the long-lived contamination ²²⁷Ac is suppressed to <5.47×10⁻⁷ (95% confidence interval) with respect to ²²⁵Ac by activity. Measured rates scale to collections of 108 kBqμA⁻¹h⁻¹ of directly produced ²²⁵Ac¹⁹F₂⁺.

