Flat-field EUV spectrometer and its performance test by Penning discharge source

Abstract

A high-resolution extreme ultraviolet (EUV) spectrometer is developed to diagnose the magnetically confined plasmas in the spectral region of 5-50 nm. The spectrometer consists a holographic aberration-corrected concave grating, an entrance slit, an x-ray shutter and a deep-cooled back-illuminated CCD camera. This paper presents the spectrometer structure, the spectral resolution simulation. The spectrometer is tested by a Penning discharge light source which is a convenient wavelength calibration source working at EUV spectral range. This light source emits a number of standard spectral lines with different combinations of discharge gas and cathode material, which will provide different standard spectral lines for wavelength calibration and spectral resolution evaluation. Results show that the spectral resolution is about 0.015 nm at 20 nm which agrees with the design goal.