Ion-assisted magnetron sputter deposition of B_4C doped Ni/Ti multilayer mirrors

摘要

Ion-assisted magnetron sputter deposition have been used to deposit Ni/Ti multilayer neutron mirrors. Improved interface widths were obtained by using B4C doping, to eliminate nanocrystallites by amorphization, and a two-stage modulated ion assistance, to obtain abrupt and smooth interfaces. In situ high-energy wide angle X-ray scattering during multilayer depositions was used to monitor the microstructure evolution and to determine the most favourable growth conditions. Post growth X-ray reflectometry in combination with high resolution transmission electron microscopy confirmed the amorhization and revealed significant improvements in interface widths and reduction of kinetic roughening upon applying B_4C doping and modulated ion assistance during growth. Significant improvement of neutron supermirror performance is predicted by employing this technique.