Influence of heating on neutron multilayer mirror

Tamura, Itaru; Arai, Masaji; Maruyama, Ryuji; Soyama, Kazuhiko

no journal, , 

For upgrading the neutron beam facility of the JRR-3, neutron guides are planned to be installed close to the liquid hydrogen moderator, therefore a temperature rise of the neutron guide by nuclear radiation heating is expected. It is known that the performance of a neutron supermirror is degraded by heating. In order to investigate the influence of heating on the performance of the neutron supermirror, reflectivity profiles of the heated multilayer mirrors which were coated by ion beam sputtering technique were measured. Thickness of diffusion layer and interface roughness were analyzed by using these reflectivity profiles. It was found that the thickness of the Ni/Ti multilayer mirror was reduced by 2% and the intensity of the first Bragg reflection was reduced to one third at 443K by using X-ray reflectometer.