Grazing incidence spectrometer with variable angle of incidence.

Area of Science:

• Atomic and Molecular Physics
• Plasma Physics
• Spectroscopy

Background:

• Grazing incidence spectrometers are crucial for analyzing extreme ultraviolet (EUV) radiation.
• Optimizing grating performance and minimizing higher-order spectral contamination are key challenges in EUV spectroscopy.

Purpose of the Study:

• To describe a novel grazing incidence spectrometer for the 10-600 A wavelength range.
• To demonstrate the instrument's capability to reduce second-order spectral interference.
• To showcase its application in time-resolved plasma emission analysis.

Main Methods:

• Utilized a 1-m concave grating spectrometer with interchangeable 600 lines/mm or 3600 lines/mm gratings.
• Employed a continuously variable angle of incidence (89-80 degrees) to optimize reflectivity and minimize higher-order spectra.
• Incorporated two independent detectors for simultaneous measurement of adjacent spectral lines.

Main Results:

• Demonstrated significant reduction of second-order spectra for C V and O VII lines.
• Achieved a spectral resolution (lambda/Deltalambda) better than 1600 at 66 A.
• Successfully performed time-resolved measurements of N VI and N VII lines from a thetapinch plasma.

Conclusions:

• The developed grazing incidence spectrometer offers enhanced performance for EUV spectral analysis.
• The variable angle of incidence is effective in suppressing unwanted higher-order spectral lines.
• The instrument is well-suited for detailed studies of transient plasma phenomena.