Multiply Charged Ion Irradiation Effects on Thin Film Superconductors

High-fidelity detection of multiply charged ions (MCIs) requires materials and systems sensitive to their unique potential and kinetic energy deposition signatures. MCIs occur naturally in the near-Earth space environment as a component of the solar wind and also appear in applied settings such as high field laser-surface interactions and in regions near the walls of a fusion reactors. Decades of research have revealed that MCI-surface impacts in any of these contexts release stored ion energy in a complex array of secondary electrons, photons, and ions which are tied to the fundamental atomic and solid-state physics of the particular ion and surface under investigation. Here we investigate the use of superconducting thin films as a path to MCI detection utilizing ions extracted from the Clemson University Electron Beam Ion Trap (CUEBIT) facility. Thin Nb films were exposed to a range of kinetic energies and, through varying charge states, potential energies using incident Argon (ArQ+) and Neon (NeQ+) ions. Surface modification and erosion effects introduced by the MCIs were quantified using atomic force microscopy measurements at room temperature. Additional low-temperature measurements probed the effects of the ions on the film quality as it related to transition temperature and critical current.