Abstract: In the process and by means of the apparatus, several radiation sources (1) arranged in a row, whose emitted radiation intensity distribution is not rotationally symmetrical, are imaged by means of a first, noncentrically imaging functional element (5), then each beam bundle (9) is rotated by means of a beam-rotating element (7), and the beam components of the rotated beam bundles (9) not imaged by the first functional element (5) are imaged by means of a second, noncentrically imaging functional element (11). The functional elements (5, 11) and their locations are chosen so that parallel beam bundles (9) are produced which are focused with a spherical lens (15) into a spatial zone (3). The apparatus according to this invention provides in a simple way a good focusing ability for several individual beams.