3-D Transient Process Calculations For Fast Cycling Superferric Accelerator Magnets

Fast cycling superferric magnets are planned for use in the new International Accelerator Facility for Antiprotons and Ion Research (FAIR) at GSI, Darmstadt. The efficiency of this magnet is basically defined by the AC loss at liquid helium temperatures in the construction elements of the dipoles and quadrupoles (iron yoke, coil, beam pipe restraints and suspension). A detailed knowledge of the 3D magnetic field, the eddy current distributions and their transient behavior is necessary to minimize the hysteresis and the eddy current losses through the use of an appropriate design. Methodical problems are considered for finite element calculations (ANSYS) of eddy currents in a laminated iron yoke. The results for window-frame dipoles and quadrupoles of the Nuclotron type are given. We present the influence of nonlinear and anisotropic magnetic and electrical properties of laminated steel and of bulk restraint elements