Neutron reflectivities of Ni-Mn and Ni-Ti multilayers for monochromators and supermirrors.

概要

論文の詳細を見る
Multilayer films for neutron mirror were made by vacuum depositing thin films of Ni and Mn or Ni and Ti on a glass plate alternately. Their neutron reflectivities were measured as a function of neutron wavelength by the time-of-flight technique. For Ni-Mn multilayer monochromators, the numbers of layers necessary to give a nearly perfect reflection (>90%) at the main Bragg peak, were found to be 7, 11 and 21 for layer thick-nesses of 163, 112 and 83A, respectively. The reflectivities obtained experimentally were compared with those calculated with the method applying the conventional optics, and their agreements were quantitatively reasonable. Moreover, for supermirrors, the num-bers of layers and the distributions of layer thicknesses were examined in order to get a reflectivity of near unity down to the wavelength much shorter than the critical wave-length of a totally reflecting mirror of Ni. The reflectivity of a supermirror consisting of 160 layers of Ni and Ti was observed to behave like that of a totally reflecting mirror with the critical wavelength of 1/2.5 time as long as that of the conventional Ni mirror. Such a supermirror can be used to improve much the characteristics of the neutron guide tube.
一般社団法人日本原子力学会の論文