X-ray emission from neon-like Fe XVII has been measured with high-resolution spectrometers from laboratory or celestial sources for nearly seven decades. Two of the strongest lines regularly identified in these spectra are the 1P1 → 1S0 resonance and the 3D1 → 1S0 intercombination line, known as 3C and 3D, respectively. This paper gives a brief overview of measurements of the intensities of the lines 3C and 3D from laboratory and celestial sources and their comparison to model calculations, with an emphasis on measurements completed using an electron beam ion trap. It includes a discussion of the measured absolute cross sections compared with results from modern atomic theory calculations as well as the diagnostic utility of the relative intensity, R = I3C/I3CD, as it applies to the interpretation of spectra measured from the Sun and extra-solar sources. PACS Nos.: 32.30.Rj, 32.30.–r, 32.70.Cs, 52.72.+v, 95.85.Nv, 96.60.P–, 97.10.Ex
Measurements of L‐shell X‐ray emission lines of neonlike europium on an electron beam ion trap
