Ultra-low doping of silver thin films with thorium: Detection beyond the limits of conventional methods

This study introduces a novel method for simulating internal radiation damage in thin films of FCC metals, utilizing small-volume electroless deposition to achieve controlled, homogenously distributed ultra-low concentrations of radioactive ²²⁸Th atoms within Ag films. We have explored the ²²⁸Th chemical state and location in the films and its effect on film morphology. The films were characterized using nuclear spectroscopy and autoradiography due to the sub-ppb to sub-ppm ²²⁸Th content, where conventional characterization methods fail due to their detection limit. We found that higher ²²⁸Th concentrations in the bath resulted, unexpectedly, in lower film activity. This study enhances our understanding of the role of Th in Ag thin film deposition and lays a foundation for future research on internal radiation damage in FCC metals, particularly focusing on the effects of recoil atoms in the films during α-emission events.