Neutron supermirror

A neutron supermirror is a highly polished surface used in connection with neutron beams.

Supermirrors are produced by depositing and polishing large numbers of layers of a reflecting substance, such as silicon, nickel, titanium or nickel/titanium composite, on a substrate. In this way, the critical angle of total reflection becomes $n\cdot\theta_c$, where $n$ is the number of layers and $\theta_c$ the angle of total reflection for a single layer.