<title>X-ray multilayer-coated reflection gratings: theory and applications</title>

AbstractESA’s X-ray Astronomy Mission, XMM, scheduled for launch in 1998, is the second of four cornerstones of ESA’s long term science program Horizon 2000. Covering the range from about 0.1 to 10 keV, it will provide a high throughput of 5000 cm2 at 7 keV with three independant telescopes, and have a spatial resolution better than 30 arcsec. Broadband spectrophotometry is provided by CCD cameras while reflection gratings provide medium resolution spectroscopy (resolving power of about 400) in the range 0.3–3 keV. Long uninterrupted observations will be made from the 24 hr period, highly eccentric orbit, reaching a sensitivity approaching 10−15 erg cm−2 s−1 in one orbit. A 30 cm UV/optical telescope is bore-sighted with the x-ray telescopes to provide simultaneous optical counterparts to the numerous serendipitous X-ray sources which will be detected during every observation.

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X-ray scattering applications using pulsed x-ray sources

10.1117/12.331844 ◽

1998 ◽

Author(s):

Bennett C. Larson

Keyword(s):

X Ray ◽

Title X ◽

X Ray Scattering ◽

Ray Scattering

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Binary Amplitude Reflection Gratings for X-ray Shearing and Hartmann Wavefront Sensors

Sensors ◽

10.3390/s21020536 ◽

2021 ◽

Vol 21 (2) ◽

pp. 536

Author(s):

Kenneth A. Goldberg ◽

Antoine Wojdyla ◽

Diane Bryant

Keyword(s):

Operating Conditions ◽

Design Parameters ◽

Wavefront Aberration ◽

Light Sources ◽

Wavefront Sensors ◽

X Ray ◽

New Class ◽

Coherent Wave ◽

Reflection Gratings ◽

Dynamic Operating

New, high-coherent-flux X-ray beamlines at synchrotron and free-electron laser light sources rely on wavefront sensors to achieve and maintain optimal alignment under dynamic operating conditions. This includes feedback to adaptive X-ray optics. We describe the design and modeling of a new class of binary-amplitude reflective gratings for shearing interferometry and Hartmann wavefront sensing. Compact arrays of deeply etched gratings illuminated at glancing incidence can withstand higher power densities than transmission membranes and can be designed to operate across a broad range of photon energies with a fixed grating-to-detector distance. Coherent wave-propagation is used to study the energy bandwidth of individual elements in an array and to set the design parameters. We observe that shearing operates well over a ±10% bandwidth, while Hartmann can be extended to ±30% or more, in our configuration. We apply this methodology to the design of a wavefront sensor for a soft X-ray beamline operating from 230 eV to 1400 eV and model shearing and Hartmann tests in the presence of varying wavefront aberration types and magnitudes.

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