Impact of the Magnet Alignment and Field Errors on the Output Uniform Beam at the DONES HEBT Line

IFMIF-DONES will be a facility devoted to study the degradation of advanced materials for operation of fusion reactors. Motivated by the need of optimizing the neutron irradiation to the materials samples, the HEBT line of the deuteron DONES (DEMO Oriented Neutron Source) accelerator is based on non-linear magnetic fields. By using octupoles and dodecapoles magnets, it is possible to shape the beam profile to achieve the demanded rectangular uniform distribution across the flat top of the beam profile, with high edge peaks in the horizontal direction. Special optics conditions are obtained with a proper setting of quadrupole magnets to minimize the x-y coupling. Additionally, the high beam power (5 MW, for a 125 mA, 40 MeV deuteron beam) in conjunction with the huge space charge makes challenging the HEBT line design to avoid non-controlled losses, except in the devoted scrapers. A comprehensive beam dynamics analysis has been made using TraceWin code. It includes extensive error studies to define tolerances and verify the robustness of the design with respect to magnet misalignment, power supply instabilities and injection parameters.