Abstract: An angle measurement system for an ion beam includes a flag defining first and second features, wherein the second feature has a variable spacing from the first feature, a mechanism to translate the flag along a translation path so that the flag intercepts at least a portion of the ion beam, and a sensing device to detect the ion beam for different flag positions along the translation path and produce a sensor signal in response to the detected ion beam. The sensor signal and corresponding positions of the flag are representative of a vertical beam angle of the ion beam in a vertical plane. The sensing device may include a mask and a mechanism to translate the mask in order to define a beam current sensor on a portion of an associated Faraday sensor.