A method of measuring ion dose in a plasma immersion ion implantation reactor during ion implantation of a selected species into a workpiece includes placing the workpiece on a pedestal in the reactor and feeding into the reactor a process gas comprising a species to be implanted into the workpiece, and then coupling RF plasma source power to a plasma in the reactor. It further includes coupling RF bias power to the workpiece by an RF bias power generator that is coupled to the workpiece through a bias feedpoint of the reactor and measuring RF current at the feedpoint to generate a current-related value, and then integrating the current-related over time to produce an ion implantation dose-related value.