A method for charged particle beam processing of a work piece, comprising: emitting ions from an ion source; forming the ions into an ion beam; directing the ion beam through an optical column having optical components positioned along an optical axis; directing the ion beam through a reference aperture to form a reference beam having a reference beam current and a reference beam shape; and adjusting the optical components to provide a desired reference beam profile at the work piece surface whereby the reference beam is aligned with the axis of the optical column and focused onto the work piece using selected parameters of said optical components so that the reference beam has a profile with a sharp edge; - using a working aperture to form a working beam by directing the ion beam through the working aperture instead of through the reference aperture; the working beam having a working beam current that is greater than the reference beam current, a working beam shape on the work piece surface that is different from the reference beam shape, the working aperture having at least one dimension that corresponds to at least one dimension of the reference aperture, whereby the working beam is aligned with the axis of the optical column and focused onto the work piece using the same optical component parameters used to align and focus the reference beam, wherein the reference beam profile includes an edge profile along a first direction and the working beam has the same edge profile along the same direction, thereby providing a higher current working beam to process a work piece more rapidly than the reference beam, while providing an edge sharpness that is similar to that of the reference beam in at least one direction; - processing the work piece using the working beam. emitting ions from an ion source; forming the ions into an ion beam; directing the ion beam through an optical column having optical components positioned along an optical axis; directing the ion beam through a reference aperture to form a reference beam having a reference beam current and a reference beam shape; and adjusting the optical components to provide a desired reference beam profile at the work piece surface whereby the reference beam is aligned with the axis of the optical column and focused onto the work piece using selected parameters of said optical components so that the reference beam has a profile with a sharp edge; - using a working aperture to form a working beam by directing the ion beam through the working aperture instead of through the reference aperture; the working beam having a working beam current that is greater than the reference beam current, a working beam shape on the work piece surface that is different from the reference beam shape, the working aperture having at least one dimension that corresponds to at least one dimension of the reference aperture, whereby the working beam is aligned with the axis of the optical column and focused onto the work piece using the same optical component parameters used to align and focus the reference beam, wherein the reference beam profile includes an edge profile along a first direction and the working beam has the same edge profile along the same direction, thereby providing a higher current working beam to process a work piece more rapidly than the reference beam, while providing an edge sharpness that is similar to that of the reference beam in at least one direction; - processing the work piece using the working beam. - using a working aperture to form a working beam by directing the ion beam through the working aperture instead of through the reference aperture; the working beam having a working beam current that is greater than the reference beam current, a working beam shape on the work piece surface that is different from the reference beam shape, the working aperture having at least one dimension that corresponds to at least one dimension of the reference aperture, whereby the working beam is aligned with the axis of the optical column and focused onto the work piece using the same optical component parameters used to align and focus the reference beam, wherein the reference beam profile includes an edge profile along a first direction and the working beam has the same edge profile along the same direction, thereby providing a higher current working beam to process a work piece more rapidly than the reference beam, while providing an edge sharpness that is similar to that of the reference beam in at least one direction; - processing the work piece using the working beam.