A method for aligning a projected beam on a reflector in a reflective-type beam detector, the method including adjusting the projected beam so as to: project on to substantially all, if not all, of a reflective surface of the reflector; or project on to at least a portion of a reflective surface of the reflector until a constant, or within a predetermined threshold of a constant, signal is received from the reflector; and detecting one or more edges of the reflective surface of the reflector and thereby: centering the projected beam, so as to align an approximate center of the projected beam on, or within a predetermined threshold of, an approximate center of the reflective surface of the reflector; and/or determining a shape or profile of the reflector.