Focusing System
The figure below shows the Super-FRS focusing system: the last section of the coupling beamline from the SIS-100 or from the SIS-18 synchrotrons to the Super-FRS target, FPF0. The quadrupole triplets or doublets are used as a unit, i.e., all quadrupoles within a multiplet act together. For low energy beams, which generally mean those directly from the SIS-18, some quadrupoles may be switched off, in order to keep the remaining active quadrupoles well into their working fields. In the figure, which is for a beam of magnetic rigidity 55 Tm, only eight of the possible ten quadrupoles are used. The unused quadrupoles are uncolored in the figure (blue-colored quadrupoles are vertically focusing, red-colored quadrupoles are horizontally focusing).