Extreme ultraviolet spectra fromN-shell ions of Gd, Dy and W

Measurements of extreme ultraviolet radiation from gadolinium, dysprosium and tungsten ions with an open n = 4 shell were performed at the National Institute of Standards and Technology. The ions were produced and confined in an electron beam ion trap, and the spectra were recorded with a flat-field grazing-incidence spectrometer in the wavelength range 3.5–17.5 nm. These data are useful for the development of future lithography sources and for diagnostics of hot plasmas in fusion devices.