Characterization of a Flat-Field Grazing-Incidence XUV Spectrometer

Area of Science:

• Plasma Physics
• Spectroscopy
• Atomic and Molecular Physics

Background:

• Dense hot microplasmas are crucial in various scientific fields, including astrophysics and inertial confinement fusion.
• Characterizing these plasmas requires advanced spectroscopic techniques capable of operating in the extreme ultraviolet (XUV) range.
• Existing methods often face limitations in spectral resolution and efficiency for microplasma diagnostics.

Purpose of the Study:

• To develop and characterize a novel XUV spectrometer for analyzing dense hot microplasmas.
• To achieve high spectral resolution in the 50–300 Å wavelength range.
• To evaluate the performance of a grazing incidence flat-field reflection grating for microplasma spectroscopy.

Main Methods:

• Utilized a commercially fabricated grazing incidence flat-field reflection grating (1200 grooves/mm).
• Optimized spectral resolution by employing a curved grazing incidence mirror to image the source onto a narrow slit.
• Tested the spectrometer using a laser-produced plasma as a source and measured grating efficiencies across multiple diffraction orders.

Main Results:

• The spectrometer achieved a resolving power ranging from 1500 at 50 Å to 3600 at 200 Å with a 5-μm slit.
• Imaging aberrations of the flat-field grating were identified as the limiting factor for resolving power.
• Measured and calculated grating efficiencies for the first to fifth diffraction orders as a function of wavelength.

Conclusions:

• The developed XUV spectrometer is a viable tool for high-resolution spectral analysis of dense hot microplasmas.
• The instrument's performance demonstrates the effectiveness of using flat-field gratings with optimized imaging for XUV spectroscopy.
• The findings provide valuable data on grating efficiencies, aiding future instrument design and plasma diagnostics.