for example be embodied in the form of a packet oriented data line for example ethernet protocol token ring protocol fiber optic data cable etc particularly with such a u201c packet oriented u201d design it is also possible to have the data line 11 for the input signal and the data line 9 for the feedback signal embodied in the form of a combined data line not shown here in fig2 the two wedges 3 of the energy modulator 1 shown in fig1 are respectively shown in a position 13 in which they are spaced the maximum distance apart from each other and in a position 14 in which they are spaced the minimum distance apart from each other depicted with dashed lines the usable region 12 for the damping of the particle beam 2 10 is defined in this case by the overlapping region of the two wedges in the position 13 in which they are spaced the maximum distance apart from each other this usable region 12 is depicted in a top view in fig3 in fig3 a plurality of measurement points 15 is shown inside the usable region 12 in the exemplary embodiment shown here the measurement points 15 are arranged in the form of a regular grid the distance between two measurement points 15 in the present case is respectively constant both along a row and along a column however other patterns are basically also possible for example a cluster of points can be established in a region that is typically or more frequently struck by the.