Improvement in the synthesis of Ni/Ti neutron mirrors

摘要

Abstract: Improvement in the as-deposited structure of Ni/Ti multilayers is achieved through optimization of the sputter deposition process. In the as-deposited condition, these Ni/Ti multilayers are well suited for very high reflectivity ($GRT 95%) neutron supermirror application. Smooth layering is produced with compositionally abrupt interfaces yielding an effective roughness less than 1 nm. The deposition parameters are controlled to produce a near thermalized condition for the sputtered neutrals. The Ni/Ti multilayer system is not structurally stable, however, when subject to moderate heating ($GRT 300$DGR@C) or irradiation. The in-use degradation of interface structure from neutron irradiation may be limitation for the Ni/Ti system.!24