Spectrometer-sensitivity calibration in the extreme ultraviolet by means of branching ratios of magnetic-dipole lines

Abstract

Relative intensity measurements of various line pairs resulting from magnetic-dipole transitions within the configurations s2p2 and s2p4, in conjunction with calculated transition probabilities, have been used to determine the wavelength dependence of the sensitivity of a grazing-incidence spectrometer in the range 400–1000 Å. Emissions from Cr xix, Fe xxi, Ni xxi, Ni xxiii, Cu xxiv, and Zr xxvii ions in Princeton Large Torus tokamak discharges were used for this purpose. Absolute sensitivity of the spectrometer at selected wavelengthshad been determined by the traditional hydrogen, helium, carbon, and oxygen electric-dipole line pairs from the same discharges. Similar attempts to use transitions in the s2p3 configurations in Cr xviii, Zr xxvi, and Mo xxviii ions resulted in significant discrepancies that are ascribed to uncertainties in the corresponding calculated transition probabilities.