An ion beam neutral detector system, an ion implanter system including the detector system and a method of detecting ion beam neutrals that ensures an ion implant is meeting contamination requirements are disclosed. The detector includes an energy contamination monitor positioned with in an ion implanter system. A method of the invention includes implanting the workpiece using an ion beam, and periodically detecting ion beam neutrals in the ion beam such that adjustments to the ion implanter system can be made for optimization.