METHODS AND APPARATUS FOR BEAM DENSITY MEASUREMENT IN TWO DIMENSIONS

摘要

A beam density measurement system includes a shield, a beam sensor, and an actuator. The beam sensor is positioned downstream from the shield in a direction of travel of a beam. The beam sensor is configured to sense an intensity of the beam, and the beam sensor has a long dimension and a short dimension. The actuator translates the shield relative to the beam sensor, wherein the shield blocks at least a portion of the beam from the beam sensor as the shield is translated relative to the beam sensor, and wherein measured values of the intensity associated with changes in a position of the shield relative to the beam sensor are representative of a beam density distribution of the beam in a first direction defined by the long dimension of the beam sensor.