Nonlinear optimization of beam lines

The current final focus systems of linear colliders have been designed based on the local compensation scheme proposed by Raimondi and Seryi. However, there exist remaining aberrations that deteriorate the performance of the system. This paper develops a general algorithm for the optimization of beam lines based on the computation of the high orders of the transfer map using MAD-X and Polimorphic Tracking Code. The algorithm is applied to the CLIC beam delivery system.

Figure 1

Twiss functions of the CLIC beam delivery system.

Figure 2

Horizontal and vertical rms beam sizes at the CLIC interaction point as a function of the maximum order considered in the transfer map. Both the nominal and monochromatic beams are considered. The horizontal aberrations are purely chromatic and only a small part of the vertical aberrations are geometric.

Figure 3

Horizontal and vertical rms beam sizes at the end of the CLIC collimation section as a function of the maximum order considered in the transfer map. Both the nominal and monochromatic beams are considered. The horizontal aberrations are purely chromatic.

Figure 4

Horizontal and vertical rms beam sizes at the CLIC IP for the nominal collimation system and the one with optimized chromaticity.

Figure 5

Horizontal and vertical rms beam sizes at the CLIC IP for the nominal BDS and the one fully optimized.

Figure 6

Horizontal and vertical rms beam sizes at the CLIC IP for the nominal BDS and the one linearly and nonlinearly optimized.