title: Alignment method for fabricating a parallel flat-field grating used in soft x-ray region.
abstract: Parallel flat-field gratings consist of two flat-field gratings lying on one substrate, one for 5-20 nm and the other for 2-5 nm spectral regions, and thus can be widely used in various fields to record broader spectra in the soft x-ray region. The alignment of two subgratings directly determines the resolving power of parallel flat-field gratings. The theoretical resolving power is evaluated by means of the ray-tracing method and the maximal allowable alignment error is 0.366°. Alignment is based on diffraction patterns and moiré fringes and the total alignment error in our experiment is within 0.234°. The results demonstrate that this alignment method is an effective way for fabricating parallel flat-field gratings.
authors.forename: Qingbo
authors.initials: Q
authors.lastname: Wang
authors.forename: Zhengkun
authors.initials: Z
authors.lastname: Liu
authors.forename: Yanchang
authors.initials: Y
authors.lastname: Zheng
authors.forename: Huoyao
authors.initials: H
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Yilin
authors.initials: Y
authors.lastname: Hong