title: Figure correction of a metallic ellipsoidal neutron focusing mirror.
abstract: An increasing number of neutron focusing mirrors is being adopted in neutron scattering experiments in order to provide high fluxes at sample positions, reduce measurement time, and/or increase statistical reliability. To realize a small focusing spot and high beam intensity, mirrors with both high form accuracy and low surface roughness are required. To achieve this, we propose a new figure correction technique to fabricate a two-dimensional neutron focusing mirror made with electroless nickel-phosphorus (NiP) by effectively combining ultraprecision shaper cutting and fine polishing. An arc envelope shaper cutting method is introduced to generate high form accuracy, while a fine polishing method, in which the material is removed effectively without losing profile accuracy, is developed to reduce the surface roughness of the mirror. High form accuracy in the minor-axis and the major-axis is obtained through tool profile error compensation and corrective polishing, respectively, and low surface roughness is acquired under a low polishing load. As a result, an ellipsoidal neutron focusing mirror is successfully fabricated with high form accuracy of 0.5 μm peak-to-valley and low surface roughness of 0.2 nm root-mean-square.
authors.affiliation: Ultrahigh Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Jiang
authors.initials: J
authors.lastname: Guo
authors.affiliation: Ultrahigh Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamagata
authors.affiliation: Ultrahigh Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Morita
authors.affiliation: Ultrahigh Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Takeda
authors.affiliation: Ultrahigh Precision Optics Technology Team, RIKEN Center for Advanced Photonics (RAP), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kato
authors.affiliation: Neutron Optics Group, Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hino
authors.affiliation: Graduate School of Engineering, Hokkaido University, Sapporo, Hokkaido 060-0808, Japan.
authors.forename: Michihiro
authors.initials: M
authors.lastname: Furusaka