Recent developments in X-ray lens modelling with SRW

TL;DR

This paper enhances the SRW wave-optics model for X-ray lenses by introducing new degrees of freedom to simulate manufacturing errors, misalignments, and figure errors, improving the accuracy of beam transport and imaging simulations.

Contribution

It proposes modifications to the SRW model allowing independent adjustments of lens surfaces and incorporation of metrology data, enabling more realistic lens simulations.

Findings

New model captures misalignments and manufacturing errors.

Incorporation of Zernike and Legendre polynomials improves error simulation.

Enhanced modeling impacts point spread function and beam caustics.

Abstract

The advent of 4$^\text{th}$ generation high-energy synchrotron facilities (ESRF-EBS and the planned APS-U, PETRA-IV and SPring-8 II) and free-electron lasers (Eu-XFEL and SLAC) allied with the recent demonstration of high-quality free-form refractive optics for beam shaping and optical correction has revived interest in compound refractive lenses (CRLs) as optics for beam transport, probe formation in X-ray micro- and nano-analysis as well as for imaging applications. Ideal CRLs have long been made available in the 'Synchrotron Radiation Workshop' (SRW), however, the current context requires more sophisticated modelling of X-ray lenses. In this work, we revisit the already implemented wave-optics model for an ideal X-ray lens in the projection approximation and propose modifications to it as to allow more degrees of freedom to both the front and back surfaces independently, which enables to reproduce misalignments and manufacturing errors commonly found in X-ray lenses. For the cases where simply tilting and transversely offsetting the parabolic sections of a CRL is not enough, we present the possibility of generating the figure errors by using Zernike and Legendre polynomials or directly adding metrology data to the lenses. We present the effects of each new degree of freedom by calculating their impact on point spread function and the beam caustics.