Abstract: A system for shaping a radiation beam exiting from a radiation source. The system includes a mount coupleable to the radiation source. The mount has a beam aperture with a tapered inner surface extending through the mount, through which the radiation beam passes. The system further includes a die having a tapered outer surface capable of engaging the tapered inner surface of the beam aperture. The die has a beam window extending through the die which is substantially transparent at at least a selected radiation power such that the radiation emerging from the beam window has the same size and shape as the beam window.