D, He and Li sputtering of liquid eutectic Sn-Li

The absolute sputtering yields from bombardment of D⁺, He⁺ and Li⁺ on liquid tin-lithium eutectic have been measured and modeled at energies between 200 and 1000 eV. The Ion-surface InterAction Experiment (IIAX) has been optimized to reliably measure the absolute sputtering yield of many ion-target combinations including solid and liquid lithium. A Colutron ion source is used to create and accelerate gaseous or metal ions onto a liquid metal target. The bombarding ions are mass-selected through an E X B filter and decelerated near the target. The target can be rotated in order to provide variation in the angle of incidence. Deuterium plasma from a hollow cathode source is used to remove any remaining oxides. Upon melting of the sample a thin oxide layer forms and is cleaved by an in situ arm. Results show that sputtering yields from liquid tin-lithium are larger than pure lithium. In addition, modeling with VFTRIM-3D confirms that Li atoms segregate to the surface of liquid tin-lithium. This is consistent with results of ion fraction of sputtered atoms, which show a sputtered-atom ion fraction of 65% for liquid tin-lithium, equal to pure liquid lithium, and <10% for solid tin-lithium.