An ion implantation system measurement system may have a scan arm (166) that rotates about an axis (184) and a workpiece support (168) to translate a workpiece through the ion beam (112). A first measurement component (162) may be downstream of the scan arm and provides a first signal from the ion beam. A second measurement component (164) with a mask (190) and a blocking plate (202) may be coupled (182) to the scan arm to provide a second signal from the ion beam with the rotation of the scan arm; wherein the mask permits varying amounts of the ion radiation from the ion beam to enter a Faraday cup (200) based on an angular orientation between the mask and the ion beam; and the blocking plate selectively blocks the ion beam to the Faraday cup based on the rotation of the scan arm. A controller is configured to determining a size of the ion beam and a relative orientation between the ion beam and the workpiece based, at least in part, on the one or more signals from the measurement component(s).