Neutron reflectometer

The surface physics research using thermal neutrons or cold neutrons has been carried out so far, but the weak signals were always the problem. In the field of ultracold neutrons, the existence of hydrogen on metallic mirror surfaces brings about the shortening of the confinement life of ultracold neutrons in neutron bottles, therefore surface phenomena are the problem. By confining ultracold neutrons in the bottle made of the material which is the object of surface research, there is the possibility to carry out precision surface physics experiment. In this report, on the research of surface physics and chemistry, the experimental apparatuses utilizing the total reflection of thermal neutrons and cold neutrons and a part of the fields of research are introduced. Neutron reflectometers are those for knowing the potential structure of sample surfaces to neutrons by making the total reflection of the neutrons on the mirror surfaces of the samples. By measuring the kappa dependence of neutron reflectivity, the information on atomic configuration and magnetic structure in the direction of normal to sample surfaces can be obtained. The examples of neutron reflectometers are shown. The examples of the experimental results are reported. (K.I.)