Design and fabrication of a supermirror with smooth and broad response for hard x-ray telescopes

Yao, Youwei; Kunieda, H.; Matsumoto, Hironori; Tamura, Kouichi; Miyata, Yusuke

doi:10.1364/ao.52.006824

Cited by 21 publications

(17 citation statements)

References 15 publications

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“…In particular, manipulating the thickness of the top several layers will reduce the dips between the total reflection part and the first Bragg peak in the x-ray reflectivity profile. Yao et al 17 demonstrated a design method to smooth the reflectivity curve profile of a supermirror. This may help us achieve a more efficient design in the future.…”

Section: Discussion and Summarymentioning

confidence: 99%

Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H)

Tamura

Kunieda

Miyata

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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Abstract. We designed depth-graded multilayers, so-called supermirrors, with platinum/carbon (Pt/C) layer pairs for the Hard X-Ray Telescope (HXT) that was on-board the sixth Japanese X-Ray Astronomy Satellite Hitomi (ASTRO-H). The HXT has multinested thin foil optics, and the grazing angles of the x-ray mirrors are 0.07 to 0.27 deg. Supermirrors for HXTs are designed to provide a broad energy response (up to 80 keV) for astronomical requests. Under practical boundary conditions, we establish a block method applying empirical rules to maximize the integrated reflectivity. We fabricated Pt/C supermirrors using a DC magnetron sputtering system. The reflectivity of the mirrors was measured in a synchrotron radiation facility, SPring-8. We describe the design method for the supermirrors and our results.

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Section: Discussion and Summarymentioning

confidence: 99%

Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H)

Tamura

Kunieda

Miyata

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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“…Smaller σ values lead to greater side lobe suppression, however a value for σ that is too small can lead to Γ values that are too close to 0 or 1 at the boundary of the structure; in that case the design would require layers that are too thin to fabricate in practice. For example, base on our ability on Pt/C multilayer deposition (DC magnetron sputtering) [18], the smallest achievable layer thickness is ~0.6 nm, so a value of σ ~0.7 is optimal. The solution of Eq.…”

Section: Design Examplesmentioning

confidence: 99%

Suppression of reflected side lobes in narrow-band X-ray multilayer coatings

Yao

Kunieda

2019

Opt. Express

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We present an analytical method for the design of narrow-band X-ray multilayer coatings having greatly reduced reflected side-lobe intensity, for the realization of X-ray mirrors that have improved spectral purity. The method uses a specific variation of the individual layer thicknesses as a function of depth in the multilayer stack, derived from Laplace transform analysis of the multilayer's reflectance profile. The design process and mathematical foundations are outlined. Pt/C multilayers with 5 nm d-spacing for hard X-rays are designed, fabricated and measured to demonstrate the validity and effectiveness of the method are presented. As an extrapolation, three additional side lobe suppressed multilayers for soft X-rays and EUVs are also designed and investigated: 1) Cr/Sc multilayer for soft Xrays (4.96 nm wavelength) at high grazing angle (30°), 2) Mo/Si multilayer for EUV (13.5 nm wavelength) at normal incidence angle and 3) SiC/Mg multilayer for EUV (30.4 nm wavelength) at normal incidence angle. The calculated reflectances demonstrate that the presented method is robust for the energy range from X-rays to EUVs.

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“…Similarly, monochromatic light is reflected over a range of incident angles. Several approaches to obtain such depth-graded structures were considered theoretically, based on numerical optimization [24][25][26][27] or a combination of analytical designing and numerical optimization. [28][29][30][31] In both methods, solving the so-called inverse problem is usually required as the final step, which consists of the minimization of a certain merit function that characterizes the deviation of the calculated reflectivity profile from the desired one.…”

Section: B Broadband Multilayer Mirrormentioning

confidence: 99%

Spectral tailoring of nanoscale EUV and soft x-ray multilayer optics

Huang

Медведев

Kruijs

et al. 2017

Applied Physics Reviews

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Extreme ultraviolet and soft X-ray (XUV) multilayer optics have experienced significant development over the past few years, particularly on controlling the spectral characteristics of light for advanced applications like EUV photolithography, space observation, and accelerator- or lab-based XUV experiments. Both planar and three dimensional multilayer structures have been developed to tailor the spectral response in a wide wavelength range. For the planar multilayer optics, different layered schemes are explored. Stacks of periodic multilayers and capping layers are demonstrated to achieve multi-channel reflection or suppression of the reflective properties. Aperiodic multilayer structures enable broadband reflection both in angles and wavelengths, with the possibility of polarization control. The broad wavelength band multilayer is also used to shape attosecond pulses for the study of ultrafast phenomena. Narrowband multilayer monochromators are delivered to bridge the resolution gap between crystals and regular multilayers. High spectral purity multilayers with innovated anti-reflection structures are shown to select spectrally clean XUV radiation from broadband X-ray sources, especially the plasma sources for EUV lithography. Significant progress is also made in the three dimensional multilayer optics, i.e., combining micro- and nanostructures with multilayers, in order to provide new freedom to tune the spectral response. Several kinds of multilayer gratings, including multilayer coated gratings, sliced multilayer gratings, and lamellar multilayer gratings are being pursued for high resolution and high efficiency XUV spectrometers/monochromators, with their advantages and disadvantages, respectively. Multilayer diffraction optics are also developed for spectral purity enhancement. New structures like gratings, zone plates, and pyramids that obtain full suppression of the unwanted radiation and high XUV reflectance are reviewed. Based on the present achievement of the spectral tailoring multilayer optics, the remaining challenges and opportunities for future researches are discussed.

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Design and fabrication of a supermirror with smooth and broad response for hard x-ray telescopes

Cited by 21 publications

References 15 publications

Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H)

Supermirror design for Hard X-Ray Telescopes on-board Hitomi (ASTRO-H)

Suppression of reflected side lobes in narrow-band X-ray multilayer coatings

Spectral tailoring of nanoscale EUV and soft x-ray multilayer optics

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