A method for irradiating a target with a beam of energetic radiation composed of electrically charged particles, wherein the target comprises an exposure region where an exposure by said beam is to be performed, the method comprising the steps of - defining a multitude of pattern pixels located at fixed pixel locations (px, px0, px1) within said exposure region, - dividing said exposure region into a number of stripes (s1, s2, s3) of predefined width, - defining, for each stripe, a multitude of exposure positions (px0, px1) on the target, each exposure position representing the location of one of a multitude of exposure spots, the exposure spots having uniform size and shape and each exposure spot covering at least one pattern pixel, - providing a pattern definition device having a plurality of apertures transparent to said radiation, - illuminating said pattern definition device by means of an illuminating wide beam (lb), which traverses the pattern definition device through said apertures thus forming a patterned beam (pb) consisting of a corresponding plurality of beamlets, - forming said patterned beam into a pattern image (pm) on the location of the target, said pattern image comprising the images of at least part of the plurality of apertures, which images sequentially expose the exposure spots in accordance with a desired pattern, and - generating a relative movement between said target and the pattern definition device producing a movement of said pattern image on the target according to a path corresponding to said stripes, wherein the width of the pattern image (pm), taken across the direction of movement (sd) is at least the width of the respective stripes, wherein defining a multitude of exposure positions (px0, px1) is performed with regard to a number of mutually separate cluster areas (L4, L9) defined at respective fixed locations on the target, and comprises: - defining locations of the exposure positions such that each exposure position is within one of the cluster areas (L4, L9), each of said cluster areas comprising a number of exposure positions arranged such that each exposure position (px0, px1) is within a given neighboring distance (ub; ex, ey) to at least one exposure position of the same cluster area, wherein said neighboring distance is smaller than a size of the images of the apertures generated on the target, wherein the cluster areas are separated from each other by spaces free of exposure positions, said spaces having a width (ux, uy; vx, vy) which is at least the double of said neighboring distance (ub; ex, ey) along at least one direction within the exposure region. - defining a multitude of pattern pixels located at fixed pixel locations (px, px0, px1) within said exposure region, - dividing said exposure region into a number of stripes (s1, s2, s3) of predefined width, - defining, for each stripe, a multitude of exposure positions (px0, px1) on the target, each exposure position representing the location of one of a multitude of exposure spots, the exposure spots having uniform size and shape and each exposure spot covering at least one pattern pixel, - providing a pattern definition device having a plurality of apertures transparent to said radiation, - illuminating said pattern definition device by means of an illuminating wide beam (lb), which traverses the pattern definition device through said apertures thus forming a patterned beam (pb) consisting of a corresponding plurality of beamlets, - forming said patterned beam into a pattern image (pm) on the location of the target, said pattern image comprising the images of at least part of the plurality of apertures, which images sequentially expose the exposure spots in accordance with a desired pattern, and - generating a relative movement between said target and the pattern definition device producing a movement of said pattern image on the target according to a path corresponding to said stripes, wherein the width of the pattern image (pm), taken across the direction of movement (sd) is at least the width of the respective stripes, - defining locations of the exposure positions such that each exposure position is within one of the cluster areas (L4, L9), each of said cluster areas comprising a number of exposure positions arranged such that each exposure position (px0, px1) is within a given neighboring distance (ub; ex, ey) to at least one exposure position of the same cluster area,