Open AccessCharacterization and on‐line adjustment of the sagittal‐bent Laue crystal profile
Author(s) -
Dong Weiwei,
Cai Quan,
Yang Fugui,
Liu Xu,
Yang Jiaowang,
Diao Qianshun,
Liu Peng,
Zhang Xiaowei,
Hu Lingfei
Publication year - 2018
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577518008056
Subject(s) - bent molecular geometry , crystal (programming language) , monochromator , radius of curvature , optics , radius , curvature , bending , sagittal plane , line (geometry) , bend radius , materials science , physics , geometry , mathematics , wavelength , medicine , mean curvature , computer security , mean curvature flow , computer science , composite material , radiology , programming language
The sagittal‐bent Laue monochromator can provide an ideal way to focus high‐energy X‐ray beams. However, the anticlastic curvature induced by sagittal bending has a great influence on the crystal performance. Thus, characterizing the bent‐crystal shape is very important for predicting the performance of the bent‐crystal monochromator. In this paper the crystal profile is measured by off‐line optical metrology and on‐line X‐ray experiments. The off‐line results showed that the bent‐crystal surface could be well fitted to a saddle surface apart from a redundant cubic term which was related to the different couples applied on the crystal. On‐line characterization of the meridional and the sagittal radius of the bent crystal includes double‐crystal topography and ray‐tracing measurement. In addition, the double‐crystal topography experiment could be used as a quick diagnostic method for the bending condition adjustment. The sagittal radius of the bent crystal was characterized through a ray‐tracing experiment by using a particularly designed tungsten mask. Moreover, rocking curves under different bending conditions were measured as well. The results were highly consistent with analytical results derived from the elastic theory. Furthermore, radii along different vertical positions under various bending conditions were measured and showed a quadratic relationship between the vertical positions and the meridional radii.