Affiliations: State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, Jilin, China
Correspondence:
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Corresponding author: Qipeng Lu, State Key Laboratory of Applied Optics, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, Jilin, China. E-mail:luqipeng@126.com
Abstract: A new monochromator is designed to develop a high performance soft X-ray
microscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF). But
owing to its high resolving power and high accurate spectrum output, there
exist many technical difficulties. In the paper presented, as two primary
design targets for the monochromator, theoretical energy resolution and
photon flux of the beamline are calculated. For wavelength scanning
mechanism, primary factors affecting the rotary angle errors are presented,
and the measuring results are 0.15'' and 0.17'' for plane mirror and plane
grating, which means that it is possible to provide sufficient scanning
precision to specific wavelength. For plane grating switching mechanism, the
repeatabilities of roll, yaw and pitch angles are 0.08'', 0.12'' and 0.05'',
which can guarantee the high accurate switch of the plane grating
effectively. After debugging, the repeatability of light spot drift reaches
to 0.7'', which further improves the performance of the monochromator. The
commissioning results show that the energy resolving power is higher than
10000 at Ar L-edge, the photon flux is higher than 1 × 108
photons/sec/200 mA, and the spatial resolution is better than 30 nm,
demonstrating that the monochromator performs very well and reaches
theoretical predictions.
