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Correction of the X-ray wavefront from compound refractive lenses using 3D printed refractive structures

DOI: 10.1107/S1600577520011765 DOI Help

Authors: Vishal Dhamgaye (Diamond Light Source; Ramanna Centre for Advanced Technology) , David Laundy (Diamond Light Source) , Sara Baldock (University, Lancaster) , Thomas Moxham (Diamond Light Source; Oxford University) , Kawal Sawhney (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Synchrotron Radiation , VOL 27

State: Published (Approved)
Published: November 2020

Open Access Open Access

Abstract: A refractive phase corrector optics is proposed for the compensation of fabrication error of X-ray optical elements. Here, at-wavelength wavefront measurements of the focused X-ray beam by knife-edge imaging technique, the design of a three-dimensional corrector plate, its fabrication by 3D printing, and use of a corrector to compensate for X-ray lens figure errors are presented. A rotationally invariant corrector was manufactured in the polymer IP-STM using additive manufacturing based on the two-photon polymerization technique. The fabricated corrector was characterized at the B16 Test beamline, Diamond Light Source, UK, showing a reduction in r.m.s. wavefront error of a Be compound refractive Lens (CRL) by a factor of six. The r.m.s. wavefront error is a figure of merit for the wavefront quality but, for X-ray lenses, with significant X-ray absorption, a form of the r.m.s. error with weighting proportional to the transmitted X-ray intensity has been proposed. The knife-edge imaging wavefront-sensing technique was adapted to measure rotationally variant wavefront errors from two different sets of Be CRL consisting of 98 and 24 lenses. The optical aberrations were then quantified using a Zernike polynomial expansion of the 2D wavefront error. The compensation by a rotationally invariant corrector plate was partial as the Be CRL wavefront error distribution was found to vary with polar angle indicating the presence of non-spherical aberration terms. A wavefront correction plate with rotationally anisotropic thickness is proposed to compensate for anisotropy in order to achieve good focusing by CRLs at beamlines operating at diffraction-limited storage rings.

Journal Keywords: X-ray optics; wavefront correction; X-ray lenses; 3D printing; knife-edge imaging

Subject Areas: Physics

Instruments: B16-Test Beamline