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Title: Optics fabrication and metrology for nanofocusing of hard x-rays

Abstract

Progress in the fabrication and metrology of both Multilayer Laue Lenses (MLLs) and Kirkpatrick-Baez (K-B) mirrors at the Advanced Photon Source (APS) is on-going as part of the world-wide race to achieve ever smaller focusing. Successful MLLs require multilayer depositions consisting of many layers. Focusing to 30 nm for 19.5 keV has been demonstrated at APS beamlines with a WSi2/Si MLL having 728 layers made at the APS. These same techniques were used to achieve a partial linear zone plate structure having a 5-nm outer most zone width and consisting of 1588 total layers as discussed below. Achromatic focusing to 80 nm of x-rays in the range {approx}7 to 22 keV by an elliptically figured K-B mirror has been demonstrated at the APS with a mirror coated at the APS. The mirror was made by profile coating a substrate with Au to achieve the elliptical surface shape. The elliptical mirror was made starting from a flat substrate. To make further progress, non-x-ray-based metrology data for real mirrors will need to be incorporated into simulations. This is being done using Fourier Optics methods as detailed below. Multilayer Laue Lens with 5-nm outermost zone - A scanning electron micrograph of a crossmore » section of a 5-nm MLL structure is shown in Fig.1, below. The bilayer structure was WSi{sub 2}/Si and a total of 1588 layers were sputter deposited at the APS. The micrograph was read to obtain the data plotted in Fig. 2. Here the d-spacing as a function of position in the lens is shown, where the d-spacing is twice the individual layer spacing A linear behavior in 1/d vs. position is needed to satisfy the zone plate law. (Owing to limited SEM resolution, the thinnest layers were subject to greater uncertainty.) This lens was used to obtain a linear focus of 19.3 nm at 19.5 keV at beamline 12-BM at the APS. Kirkpatrick-Baez mirrors and Fourier Optics Simulations - Elliptically shaped mirrors have been made by profile coating at the APS. A program to simulate the performance of such mirrors by means of Fourier Optics has recently been started. Mirror aberrations away from a perfect ellipse will be incorporated into a complex pupil function. In the absence of any aberrations, spherical waves emanating from a point source will be reflected to produce spherical waves directed to a focus. The resultant Fraunhofer diffraction pattern near the focal plane is shown in Fig. 3. Subsequent introduction of mirror aberrations will be simulated with this procedure.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC)
OSTI Identifier:
991605
Report Number(s):
ANL/XSD/CP-118784
TRN: US1007516
DOE Contract Number:
DE-AC02-06CH11357
Resource Type:
Conference
Resource Relation:
Conference: 5th International Conference on Synchrotron Radiation in Materials Science (SRMS 5); Jul. 30, 2006 - Aug. 2, 2006; Chicago, IL
Country of Publication:
United States
Language:
ENGLISH
Subject:
43 PARTICLE ACCELERATORS; ADVANCED PHOTON SOURCE; COATINGS; CROSS SECTIONS; DIFFRACTION; ELECTRONS; FABRICATION; FOCUSING; LENSES; MIRRORS; OPTICS; PERFORMANCE; PLATES; POINT SOURCES; RESOLUTION; SHAPE; SUBSTRATES; SYNCHROTRON RADIATION

Citation Formats

Macrander, A. T., Liu, C., Conley, R., Assoufid, L., Khounsary, A., Qian, J., Kewish, C. M., and X-Ray Science Division. Optics fabrication and metrology for nanofocusing of hard x-rays. United States: N. p., 2006. Web.
Macrander, A. T., Liu, C., Conley, R., Assoufid, L., Khounsary, A., Qian, J., Kewish, C. M., & X-Ray Science Division. Optics fabrication and metrology for nanofocusing of hard x-rays. United States.
Macrander, A. T., Liu, C., Conley, R., Assoufid, L., Khounsary, A., Qian, J., Kewish, C. M., and X-Ray Science Division. Sun . "Optics fabrication and metrology for nanofocusing of hard x-rays". United States. doi:.
@article{osti_991605,
title = {Optics fabrication and metrology for nanofocusing of hard x-rays},
author = {Macrander, A. T. and Liu, C. and Conley, R. and Assoufid, L. and Khounsary, A. and Qian, J. and Kewish, C. M. and X-Ray Science Division},
abstractNote = {Progress in the fabrication and metrology of both Multilayer Laue Lenses (MLLs) and Kirkpatrick-Baez (K-B) mirrors at the Advanced Photon Source (APS) is on-going as part of the world-wide race to achieve ever smaller focusing. Successful MLLs require multilayer depositions consisting of many layers. Focusing to 30 nm for 19.5 keV has been demonstrated at APS beamlines with a WSi2/Si MLL having 728 layers made at the APS. These same techniques were used to achieve a partial linear zone plate structure having a 5-nm outer most zone width and consisting of 1588 total layers as discussed below. Achromatic focusing to 80 nm of x-rays in the range {approx}7 to 22 keV by an elliptically figured K-B mirror has been demonstrated at the APS with a mirror coated at the APS. The mirror was made by profile coating a substrate with Au to achieve the elliptical surface shape. The elliptical mirror was made starting from a flat substrate. To make further progress, non-x-ray-based metrology data for real mirrors will need to be incorporated into simulations. This is being done using Fourier Optics methods as detailed below. Multilayer Laue Lens with 5-nm outermost zone - A scanning electron micrograph of a cross section of a 5-nm MLL structure is shown in Fig.1, below. The bilayer structure was WSi{sub 2}/Si and a total of 1588 layers were sputter deposited at the APS. The micrograph was read to obtain the data plotted in Fig. 2. Here the d-spacing as a function of position in the lens is shown, where the d-spacing is twice the individual layer spacing A linear behavior in 1/d vs. position is needed to satisfy the zone plate law. (Owing to limited SEM resolution, the thinnest layers were subject to greater uncertainty.) This lens was used to obtain a linear focus of 19.3 nm at 19.5 keV at beamline 12-BM at the APS. Kirkpatrick-Baez mirrors and Fourier Optics Simulations - Elliptically shaped mirrors have been made by profile coating at the APS. A program to simulate the performance of such mirrors by means of Fourier Optics has recently been started. Mirror aberrations away from a perfect ellipse will be incorporated into a complex pupil function. In the absence of any aberrations, spherical waves emanating from a point source will be reflected to produce spherical waves directed to a focus. The resultant Fraunhofer diffraction pattern near the focal plane is shown in Fig. 3. Subsequent introduction of mirror aberrations will be simulated with this procedure.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

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  • We report on a new research and development program at the Advanced Light Source, Lawrence Berkeley National Lab directed to establish both at-wavelength and conventional optical metrology techniques suitable to characterize the surface profile of super-high-quality x-ray optics with sub-microradian precision.
  • Customized flexure mechanisms and precision thermal expansion compensation are needed for the development of nanopositioning stages for hard x-ray nanofocusing and coherence preservation optics at the APS. Recent progress of such stage development is summarized in this paper, which includes: stages designed for alignment apparatus for K-B mirrors with 20 - 50 nm focal spot; alignment apparatus for six Fresnel zone plates stacking with 20 nm focal spot; stages for switchable multiple nanofocusing system; UHV hard x-ray monochromators for coherence related applications; and four-crystal hard x-ray split-and-delay line with coherence preservation. Preliminary test results for mechanical performance of these nanopositioningmore » stages are also discussed in this paper.« less
  • What is the point of developing new high-brightness light sources if beamline optics won't be available to realize the goals of nano-focusing and coherence preservation? That was one of the central questions raised during a workshop at the 2007 Advanced Light Source Users Meeting. Titled, 'Advanced X-Ray Optics Metrology for Nano-focusing and Coherence Preservation', the workshop was organized by Kenneth Goldberg and Valeriy Yashchuk (both of Lawrence Berkeley National Laboratory, LBNL), and it brought together industry representatives and researchers from Japan, Europe, and the US to discuss the state of the art and to outline the optics requirements of newmore » light sources. Many of the presentations are viewable on the workshop website http://goldberg.lbl.gov/MetrologyWorkshop07/. Many speakers shared the same view of one of the most significant challenges facing the development of new high-brightness third and fourth generation x-ray, soft x-ray, and EUV light sources: these sources place extremely high demands on the surface quality of beamline optics. In many cases, the 1-2-nm surface error specs that define the outer bounds of 'diffraction-limited' quality are beyond the reach of leading facilities and optics vendors. To focus light to 50-nm focal spots, or smaller, from reflective optics and to preserve the high coherent flux that new sources make possible, the optical surface quality and alignment tolerances must be measured in nano-meters and nano-radians. Without a significant, well-supported research effort, including the development of new metrology techniques for use both on and off the beamline, these goals will likely not be met. The scant attention this issue has garnered is evident in the stretched budgets and limited manpower currently dedicated to metrology. With many of the world's leading groups represented at the workshop, it became clear that Japan and Europe are several steps ahead of the US in this critical area. But the situation isn't all dire: several leading groups are blazing a trail forward, and the recognition of this issue is increasing. The workshop featured eleven invited talks whose presenters came from Japan, Europe, and the US.« less
  • The first test of nanoscale-focusing Kirkpatrick-Baez (KB) mirrors in the nested (or Montel) configuration used at a hard X-ray synchrotron beamline is reported. The two mirrors are both 40 mm long and coated with Pt to produce a focal length of 60 mm at 3 mrad incident angle, and collect up to a 120 {micro}m by 120 {micro}m incident X-ray beam with maximum angular acceptance of 2 mrad and a broad bandwidth of energies up to 30 keV. In an initial test a focal spot of about 150 nm in both horizontal and vertical directions was achieved with either polychromaticmore » or monochromatic beam. The nested mirror geometry, with two mirrors mounted side-by-side and perpendicular to each other, is significantly more compact and provides higher demagnification than the traditional sequential KB mirror arrangement. Ultimately, nested mirrors can focus larger divergence to improve the diffraction limit of achromatic optics. A major challenge with the fabrication of the required mirrors is the need for near-perfect mirror surfaces near the edge of at least one of the mirrors. Special polishing procedures and surface profile coating were used to preserve the mirror surface quality at the reflecting edge. Further developments aimed at achieving diffraction-limited focusing below 50 nm are underway.« less
  • The first test of nanoscale-focusing Kirkpatrick-Baez (KB) mirrors in the nested (or Montel) configuration used at a hard X-ray synchrotron beamline is reported. The two mirrors are both 40 mm long and coated with Pt to produce a focal length of 60 mm at 3 mrad incident angle, and collect up to a 120 {micro}m by 120 {micro}m incident X-ray beam with maximum angular acceptance of 2 mrad and a broad bandwidth of energies up to 30 keV. In an initial test a focal spot of about 150 nm in both horizontal and vertical directions was achieved with either polychromaticmore » or monochromatic beam. The nested mirror geometry, with two mirrors mounted side-by-side and perpendicular to each other, is significantly more compact and provides higher demagnification than the traditional sequential KB mirror arrangement. Ultimately, nested mirrors can focus larger divergence to improve the diffraction limit of achromatic optics. A major challenge with the fabrication of the required mirrors is the need for near-perfect mirror surfaces near the edge of at least one of the mirrors. Special polishing procedures and surface profile coating were used to preserve the mirror surface quality at the reflecting edge. Further developments aimed at achieving diffraction-limited focusing below 50 nm are underway.« less