As part of a charged particle cancer therapy system, a negative ion source is used to generate and accelerate an anion, such a C−, and to convert the anion to a cation, such as C6+, through use of one or more electron extraction subsystems. Initially, an electric field is pulsed across a magnetic field to generate the C− anion. Subsequent to extraction of the C− anion from a plasma region using pulsed electrodes, one or both of a hydrogen gas electron stripping system and a carbon foil electron stripping system converts the carbon anion into the cation. The resultant cation is accelerated in a synchrotron, transported along a beam-line, and targeted to a tumor resulting in ablation of the tumor.
