Kolodziej Tomasz, Stoupin Stanislav, Grizolli Walan, Krzywinski Jacek, Shi Xianbo, Kim Kwang Je, Qian Jun, Assoufid Lahsen, Shvyd'ko Yuri
Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.
Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
J Synchrotron Radiat. 2018 Mar 1;25(Pt 2):354-360. doi: 10.1107/S160057751701699X. Epub 2018 Feb 14.
Performance tests of parabolic beryllium refractive lenses, considered as X-ray focusing elements in the future X-ray free-electron laser oscillator (XFELO), are reported. Single and double refractive lenses were subject to X-ray tests, which included: surface profile, transmissivity measurements, imaging capabilities and wavefront distortion with grating interferometry. Optical metrology revealed that surface profiles were close to the design specification in terms of the figure and roughness. The transmissivity of the lenses is >94% at 8 keV and >98% at 14.4 and 18 keV. These values are close to the theoretical values of ideal lenses. Images of the bending-magnet source obtained with the lenses were close to the expected ones and did not show any significant distortion. Grating interferometry revealed that the possible wavefront distortions produced by surface and bulk lens imperfections were on the level of ∼λ/60 for 8 keV photons. Thus the Be lenses can be succesfully used as focusing and beam collimating elements in the XFELO.
本文报道了抛物面铍折射透镜作为未来X射线自由电子激光振荡器（XFELO）中的X射线聚焦元件的性能测试。对单折射透镜和双折射透镜进行了X射线测试，测试内容包括：表面轮廓、透射率测量、成像能力以及利用光栅干涉测量波前畸变。光学计量显示，表面轮廓在形状和粗糙度方面接近设计规格。透镜在8 keV时的透射率>94%，在14.4 keV和18 keV时>98%。这些值接近理想透镜的理论值。用透镜获得的弯曲磁铁源图像接近预期图像，未显示任何明显畸变。光栅干涉测量表明，对于8 keV光子，由透镜表面和体缺陷产生的可能波前畸变在~λ/60的水平。因此，铍透镜可成功用作XFELO中的聚焦和光束准直元件。
