An ion implantation system measurement system has a scan arm that rotates about an axis and a workpiece support to translate a workpiece through the ion beam. A first measurement component downstream of the scan arm provides a first signal from the ion beam. A second measurement component with a mask is coupled to the scan arm to provide a second signal from the ion beam with the rotation of the scan arm. The mask permits varying amounts of the ion radiation from the ion beam to enter a Faraday cup based on an angular orientation between the mask and the ion beam. A blocking plate selectively blocks the ion beam to the first faraday based on the rotation of the scan arm. A controller determines an angle and vertical size of the ion beam based on the first signal, second signal, and orientation between the mask and ion beam as the second measurement component rotates.