The Advanced Photon Source
a U.S. Department of Energy Office of Science User Facility

Beamline Optics Simulation and Code Development

Beamline optics simulation is essential for the new beamline development as well as for improving the beamline operation. The group specialists widely use the optics simulation suite OASYS to provide simulation support and develop integrated advanced optics simulation methods.

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HYBRID method

The HYBRID method computes diffraction effects when the beam is clipped by an aperture or mirror length and can also simulate the effect of figure errors in mirrors and gratings or thickness errors in refractive elements when diffraction is present. This method has been implemented into OASYS as a dedicated widget for the raytracing tool ShadowOui, provided with a user interface with a high level of automation.

Scanning loops

We added new widgets extending the looping mechanism embedded in OASYS, to provide accurate calculations of the specifications of mirrors, not only in terms of shape and dimension, but also critical technical details like (i) the resolution of motors to activate translations and rotations (ii) the manufacturing quality of mirrors in term of height (surface) errors.

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Thermal load loops
A new set of widgets has been developed and added to OASYS to create an iterative ab initio procedure to compute the thermal load in every critical element of the beamlines. The new tool integrates SRW for the source radiation simulation, ShadowOui for the beam propagation through beamline elements, and other tools for providing material and optical properties.
Simulation of real and complex optics

We modeled focusing bendable elliptical mirrors as realistic as possible by integrating into the simulation the real surface generated by a dynamical bending device, activated by one or two (unequal) end couples, and considering that the shape of the mirror can be trapezoidal. The surface profile generated by a bender can be calculated analytically. The implemented ShadowOui widget uses the non-linear least-square fit of the bent mirror profile to approach the ideal surface profile for a given focal condition.

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We also integrated into OASYS the wave optics simulations currently used by the Optics group to manufacture nanofocusing Zone Plates. A dedicated ShadowOui widget provides, by using the Hybrid method, accurate and realistic raytracing simulations.

WavePy 2.0

The beamline 1-BM at APS hosts a fast evaluation system based on single-grating Talbot interferometry as an at-wavelength characterization method capable of providing accurate, quantitative measurements of manufacturing imperfections of refractive optical elements. The software Wavepy 2.0 (a fully refactored version of the previous Wavepy) is coupled to reconstruct the shape of the surface of the optical elements under inspection (typically CRLs and High-Vacuum X-ray Windows) and, consequently, their thickness error profile. Wavepy 2.0 is available both as a command-line program and integrated into the OASYS graphical environment, allowing its output data to be directly and automatically used by the optical simulation tools without any further processing by the users.

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Further development includes data analysis for speckle-based and coded-mask-based methods.

User support 
The optics group staff provides support to APS and the APS upgrade project beamline optimization, optics, and thermal load simulations. Work requests can be submitted by filling the Optics Group's work request form.

 

09.07.2021