US Patent 7417242 Method of measuring ion beam position

A system, apparatus, and method for determining position and two angles of incidence of an ion beam to a surface of a workpiece is provided. A measurement apparatus having an elongate first and second sensor is coupled to a translation mechanism, wherein the first sensor extends in a first direction perpendicular to the translation, and wherein the second sensor extends at an oblique angle to the first sensor. The first and second elongate sensors sense one or more characteristics of the ion beam as the first and second sensors pass through the ion beam at a respective first time and a second time, and a controller is operable to determine a position and first and second angle of incidence of the ion beam, based, at least in part, on the one or more characteristics of the ion beam sensed by the first sensor and second sensor at the first and second times.