Design, Construction and Performance of the DESY II Magnets

Dipoles, quadrupoles and sextupoles have been designed and constructed for the new separated function synchrotron, DESY II. The special constraints for the magnets were: 12.5 Hz repetition frequency and a 50 MeV to 10 GeV energy operation range. Special care was taken in selecting the steel, chosing the thickness of laminations and designing the endfield shape. To ensure easy access to the vacuum chamber, and because there are nine inlet and outlet beam pipes to be installed, a c-type pole shape design for the dipole was chosen. The quadrupoles and sextupoles have the same cross section as the PETRA magnets, but they are different in length, lamination thickness, coils and endfield shape. Back-leg windings are applied on the dipoles to enable horizontal orbit displacements to be made. The major part of the vertical orbit correction will be made using four coils mounted on the return yokes of the sextupoles so as to create superimposed horizontal magnetic fields.