Disclosed is an X-ray beam collimator. In one configuration, the collimator comprises an X-ray collimating portion having an X-ray transmission aperture formed therein. In one configuration, an electron absorbing portion is positioned in or arranged to overlie the X-ray transmission aperture. In one configuration, the X-ray collimating portion has a thickness in a direction through the aperture greater than a thickness in the same direction of the electron absorbing portion. In one configuration, the collimator comprises an x-ray collimating portion made of a conducting first material having an x-ray transmission aperture formed therein. In one configuration, an electron absorbing portion made of a conducting second material is arranged to plug or cover the x-ray transmission aperture. In one configuration, the first material is relatively more radiodense than the second material. Also disclosed is an x-ray beam apparatus, a method of reducing ozone generation and a structure manufacturing method using the disclosed collimator.