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Long, elliptically bent, active X-ray mirrors with slope errors <200 nrad

DOI: 10.1107/S1600577517005422 DOI Help

Authors: Ioana T. Nistea (Diamond Light Source) , Simon G. Alcock (Diamond Light Source) , Paw Kristiansen (FMB Oxford Ltd) , Adam Young (FMB Oxford Ltd.)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Journal Of Synchrotron Radiation , VOL 24

State: Published (Approved)
Published: May 2017

Open Access Open Access

Abstract: Actively bent X-ray mirrors are important components of many synchrotron and X-ray free-electron laser beamlines. A high-quality optical surface and good bending performance are essential to ensure that the X-ray beam is accurately focused. Two elliptically bent X-ray mirror systems from FMB Oxford were characterized in the optical metrology laboratory at Diamond Light Source. A comparison of Diamond-NOM slope profilometry and finite-element analysis is presented to investigate how the 900 mm-long mirrors sag under gravity, and how this deformation can be adequately compensated using a single, spring-loaded compensator. It is shown that two independent mechanical actuators can accurately bend the trapezoidal substrates to a range of elliptical profiles. State-of-the-art residual slope errors of <200 nrad r.m.s. are achieved over the entire elliptical bending range. High levels of bending repeatability (ΔR/R = 0.085% and 0.156% r.m.s. for the two bending directions) and stability over 24 h (ΔR/R = 0.07% r.m.s.) provide reliable beamline performance.

Journal Keywords: X-ray active optics; mechanically bent mirrors; optical metrology; Diamond-NOM

Subject Areas: Technique Development, Physics


Technical Areas: Optics

Documents:
ie5179.pdf