Establishing a Consistent Basis for Beam Physics, Accelerator Magnet Design, and Magnetic Measurements

The paper describes the recent efforts in establishing a consistent basis for beam physics simulations and machine requirements, magnet design and manufacture, and magnetic measurements. Magnetic field measurements serve for the quality assurance of the magnet production, and for validating numerical field simulation (FEM) tools and magnet design techniques. In order to study the performance of the accelerator and to allocate a budget for magnet misalignment in the tunnel, the beam physicists require the field maps and multipole field errors of the magnet system, either from validated numerical models or from magnetic measurements. When dynamic effects in the magnet exceed the capability of numerical simulations, online field measurements are done for monitoring of the magnet behavior and thus providing direct feedback to the accelerator control room for adjusting the magnet current cycles, and to tune the high-frequency accelerator cavities. The paper describes the approaches and techniques in magnetic field measurements and numerical field computations, discusses their limitations and attempts to make them consistent with the requirements from beam physics and magnet design.