title: Simultaneous measurement of X-ray specular reflection and off-specular diffuse scattering from liquid surfaces using a two-dimensional pixel array detector: the liquid-interface reflectometer of BL37XU at SPring-8.
abstract: An X-ray reflectometer for simultaneous measurement of specular and off-specular reflection of liquid surfaces is described. The reflectometer, equipped with a two-dimensional single X-ray photon-counting pixel array detector obtained the full range of X-ray specular and off-specular reflections in an extremely short time (1 s). Both the specular and off-specular reflection of water exhibited good agreement with the predicted capillary-wave theory within the appropriate instrumental resolution. The approach is also demonstrated on an aqueous solution of 1-dodecyl-3-methylimidazolium chloride. The monolayer in which the dodecyl chain faces upwards and the Cl(-) anion locates next to the imidazolium ring formed on the water surface was found to be laterally homogeneous. The use of a pixel array detector will be particularly powerful for in situ measurements to investigate both out-of-plane and in-plane structures simultaneously, not only for liquid surfaces but also for other thin films.
authors.affiliation: Research Organization of Science and Engineering, Ritsumeikan University, Shiga, Japan.
authors.forename: Yohko F
authors.initials: YF
authors.lastname: Yano
authors.forename: Tomoya
authors.initials: T
authors.lastname: Uruga
authors.forename: Hajime
authors.initials: H
authors.lastname: Tanida
authors.forename: Hidenori
authors.initials: H
authors.lastname: Toyokawa
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Terada
authors.forename: Hironari
authors.initials: H
authors.lastname: Yamada