Laboratory Investigation of Vapor Shielding for Lithium-Coated Molybdenum in Devex

To investigate the effect of lithium on a molybdenum target, a triple Langmuir probe diagnostics and target temperature measurements are carried out. Several experimental scenarios are tested to optimize the device for the vapor shielding experiment. A lithium sputtering system is used to deposit lithium on a molybdenum target. A triple Langmuir probe is placed near the target at various pressures to estimate change of plasma density and electron temperature and their effects on vapor shielding. Temperature increase at the target is measured by a thermocouple and its relationship with plasma parameters and lithium is discussed in detail.