Soft x-ray high diffraction efficiency and spectral flux laminar-type W/B4C multilayer diffraction grating for...

Area of Science:

• X-ray optics and spectroscopy
• Materials science for advanced coatings
• Instrument development for scientific research

Background:

• Soft x-ray spectroscopy is crucial for analyzing elemental emissions, particularly Fe-L, Cu-L, and Zn-L.
• Existing flat-field spectrographs face limitations in detection limit and sensitivity.
• Improving spectral flux is key to enhancing detection sensitivity in spectrographic instruments.

Purpose of the Study:

• To design multilayer diffraction gratings for soft x-ray flat-field spectrographs.
• To enhance the detection limit and sensitivity for specific soft x-ray emissions (300-1000 eV).
• To increase spectral flux while maintaining spectral resolution and dispersion.

Main Methods:

• Utilized a super-mirror-type W/B4C multilayer coating with graded refractive index and period length.
• Optimized incidence angle to 86.03° and increased groove density to 3200 lines/mm.
• Designed a holographic varied-line-spacing spherical grating using aspherical-wavefront-recording method.

Main Results:

• Numerical simulations demonstrated a 3.2-8.2 times increase in spectral flux.
• The new design maintained spectral resolution comparable to previous designs.
• Enhanced diffraction efficiency across a wide energy range was achieved.

Conclusions:

• The developed W/B4C multilayer gratings significantly improve soft x-ray spectrograph performance.
• The design advancements enable more sensitive detection of key elemental emissions.
• This work contributes to advancements in soft x-ray spectroscopy instrumentation.