An improved double chamber ion source comprising a plasma generating chamber, a charge exchange chamber and a divider structure therebetween. The charge exchange chamber includes magnetic shielding material to reduce exposure of interior components to magnetic field lines externally generated. The double compartment ion source further comprises inclusion of a heat shield and/or a cooling system to overcome deleterious effects caused by increased temperature in the plasma generating chamber. The divider structure has a plurality of apertures having a configuration to reduce surface area on the divider structure in the charge exchange chamber.