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Title: Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser

Abstract

The Linac Coherent Light Source is upgrading its machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high-resolution soft X-ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile to have high reflectivity (or efficiency) and at the same time survive the high peak energy of the free-electron laser pulses. For these reasons the experimental damage threshold, at 900 eV, of two platinum-coated gratings with different blazed angles has been investigated. The gratings were tested at 1° grazing incidence. To validate a model for which the damage threshold on the blaze grating can be estimated by calculating the damage threshold of a mirror with an angle of incidence identical to the angle of incidence on the grating plus the blaze angle, tests on Pt-coated substrates have also been performed. The results confirmed the prediction. Uncoated silicon, platinum and SiB 3 (both deposited on a silicon substrate) were also investigated. In general, the measured damage threshold at grazing incidence is higher than that calculated under the assumption that there is no energy transport frommore » the volume where the photons are absorbed. However, it was found that, for the case of the SiB 3 coating, the grazing incidence condition did not increase the damage threshold, indicating that the energy transport away from the extinction volume is negligible.« less

Authors:
 [1];  [2];  [1];  [3];  [3];  [3];  [3]; ORCiD logo [1]
  1. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
  3. Helmholtz Zentrum Berlin fur Materialen und Energie, Berlin (Germany)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1413825
Alternate Identifier(s):
OSTI ID: 1417641
Grant/Contract Number:
AC02-76SF00515
Resource Type:
Journal Article: Published Article
Journal Name:
Journal of Synchrotron Radiation (Online)
Additional Journal Information:
Journal Name: Journal of Synchrotron Radiation (Online); Journal Volume: 25; Journal Issue: 1; Journal ID: ISSN 1600-5775
Publisher:
International Union of Crystallography
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; free-electron laser; optical damage; diffraction gratings

Citation Formats

Krzywinski, Jacek, Conley, Raymond, Moeller, Stefan, Gwalt, Grzegorz, Siewert, Frank, Waberski, Christoph, Zeschke, Thomas, and Cocco, Daniele. Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser. United States: N. p., 2018. Web. doi:10.1107/S1600577517016083.
Krzywinski, Jacek, Conley, Raymond, Moeller, Stefan, Gwalt, Grzegorz, Siewert, Frank, Waberski, Christoph, Zeschke, Thomas, & Cocco, Daniele. Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser. United States. doi:10.1107/S1600577517016083.
Krzywinski, Jacek, Conley, Raymond, Moeller, Stefan, Gwalt, Grzegorz, Siewert, Frank, Waberski, Christoph, Zeschke, Thomas, and Cocco, Daniele. Mon . "Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser". United States. doi:10.1107/S1600577517016083.
@article{osti_1413825,
title = {Damage thresholds for blaze diffraction gratings and grazing incidence optics at an X-ray free-electron laser},
author = {Krzywinski, Jacek and Conley, Raymond and Moeller, Stefan and Gwalt, Grzegorz and Siewert, Frank and Waberski, Christoph and Zeschke, Thomas and Cocco, Daniele},
abstractNote = {The Linac Coherent Light Source is upgrading its machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high-resolution soft X-ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile to have high reflectivity (or efficiency) and at the same time survive the high peak energy of the free-electron laser pulses. For these reasons the experimental damage threshold, at 900 eV, of two platinum-coated gratings with different blazed angles has been investigated. The gratings were tested at 1° grazing incidence. To validate a model for which the damage threshold on the blaze grating can be estimated by calculating the damage threshold of a mirror with an angle of incidence identical to the angle of incidence on the grating plus the blaze angle, tests on Pt-coated substrates have also been performed. The results confirmed the prediction. Uncoated silicon, platinum and SiB 3 (both deposited on a silicon substrate) were also investigated. In general, the measured damage threshold at grazing incidence is higher than that calculated under the assumption that there is no energy transport from the volume where the photons are absorbed. However, it was found that, for the case of the SiB 3 coating, the grazing incidence condition did not increase the damage threshold, indicating that the energy transport away from the extinction volume is negligible.},
doi = {10.1107/S1600577517016083},
journal = {Journal of Synchrotron Radiation (Online)},
number = 1,
volume = 25,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2018},
month = {Mon Jan 01 00:00:00 EST 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1107/S1600577517016083

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  • The Linac Coherent Light Source is upgrading its machine to high repetition rate and to extended ranges. Novel coatings, with limited surface oxidation, which are able to work at the carbon edge, are required. In addition, high-resolution soft X-ray monochromators become necessary. One of the big challenges is to design the mirror geometry and the grating profile to have high reflectivity (or efficiency) and at the same time survive the high peak energy of the free-electron laser pulses. For these reasons the experimental damage threshold, at 900 eV, of two platinum-coated gratings with different blazed angles has been investigated. Themore » gratings were tested at 1° grazing incidence. To validate a model for which the damage threshold on the blaze grating can be estimated by calculating the damage threshold of a mirror with an angle of incidence identical to the angle of incidence on the grating plus the blaze angle, tests on Pt-coated substrates have also been performed. The results confirmed the prediction. Uncoated silicon, platinum and SiB 3 (both deposited on a silicon substrate) were also investigated. In general, the measured damage threshold at grazing incidence is higher than that calculated under the assumption that there is no energy transport from the volume where the photons are absorbed. Furthermore, it was found that, for the case of the SiB 3 coating, the grazing incidence condition did not increase the damage threshold, indicating that the energy transport away from the extinction volume is negligible.« less
  • Optical elements to be used for x-ray free electron lasers (XFELs) must withstand multiple high-fluence pulses. We have used an ultraviolet laser to study the damage of two candidate materials, crystalline Si and B{sub 4}C-coated Si, emulating the temperature profile expected to occur in optics exposed to XFEL pulses. We found that the damage threshold for 10{sup 5} pulses is {approx}20% to 70% lower than the melting threshold.
  • Diffraction gratings are used from micron to nanometer wavelengths as dispersing elements in optical instruments. At shorter wavelengths, crystals can be used as diffracting elements, but due to the 3D nature of the interaction with light are wavelength selective rather than wavelength dispersing. There is an urgent need to extend grating technology into the x-ray domain of wavelengths from 1 to 0.1 nm, but this requires the use of gratings that have a faceted surface in which the facet angles are very small, typically less than 1°. Small facet angles are also required in the extreme ultra-violet and soft x-ray energymore » ranges in free electron laser applications, in order to reduce power density below a critical damage threshold. In this work, we demonstrate a technique based on anisotropic etching of silicon designed to produce very small angle facets with a high degree of perfection.« less
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  • The loss of crystallinity at the surface of a silicon single crystal exposed to intense pulsed laser irradiation has been observed by means of a grazing incidence diffraction technique. The Bragg peak is shown to disappear during melting, and gradually reappear during subsequent stages of recrystallization.