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Published on: October 11, 2016
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X-ray mirror surface figure correction with nanometre precision controlled by layer stresses simulated by FEA
1LCLS, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
Journal of Synchrotron Radiation
|January 19, 2019
Summary
Controlling X-ray mirror surface shape with layer stresses enables nanometre precision for advanced X-ray analytical techniques and free-electron laser applications. This method achieves high accuracy, overcoming limitations in current X-ray focusing optics.
Area of Science:
- Optics and Photonics
- Materials Science
- Nanotechnology
Background:
- High-energy hard X-rays enable nanoscale chemical, elemental, and structural analysis.
- Nanometre-scale surface precision of focusing optics is crucial for achieving single-nanometre spatial resolution in X-ray techniques.
- Precise control of reflective mirror surfaces is essential for preserving wavefront properties in coherent X-ray beams, particularly for X-ray free-electron laser applications.
Purpose of the Study:
- To develop a method for controlling the surface shape of multilayer-coated X-ray mirrors using layer stresses.
- To achieve nanometre-scale precision in X-ray focusing optics for enhanced analytical capabilities.
- To address the limitations in current X-ray analytical techniques imposed by optic surface precision.
Main Methods:
- Controlling mirror surface shape through induced layer stresses.
- Differentiating the desired surface profile to determine the curvature profile.
- Applying varied coating thicknesses to create differential layer thermal stresses via uniform temperature changes.
- Simulating the process using finite element analysis (FEA).
Main Results:
- The study successfully simulated the control of X-ray mirror surface shape using layer stresses.
- Finite element analysis demonstrated the feasibility of achieving nanometre-scale precision.
- A case study showed residual slope error of 0.22 µrad (r.m.s.) and residual height error of 1.42 nm (r.m.s.) between the desired and actual mirror shapes.
Conclusions:
- Layer stress engineering offers a viable method for fabricating X-ray mirrors with nanometre-scale surface precision.
- This technique can overcome current limitations in X-ray focusing optics, enabling advancements in X-ray analytical techniques and coherent X-ray beam applications.
- The FEA simulations validate the effectiveness of the proposed method for precise mirror surface control.
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