Calcium and Potassium Spectra in the EUV

Abstract

In online data bases, the entries on extreme ultraviolet (EUV) spectra of Ca are much more sparse than those of neighbouring elements such as Ar, K, Sc and Ti. This may be a result of experimental problems with Ca in the laboratory as well as of the limited role of multiply charged Ca ions in solar observations. Beam-foil EUV spectra of Ca and K are presented that provide survey data of a single element each.

EUV Beam-Foil Spectra of Titanium, Iron, Nickel, and Copper

“…Among the prominent lines of interest are the Ti XII and Ti XIII 4f-5g yrast transition arrays. A prominent line pair is formed by the Ti XIV 2s 2 2p 5 2 P o 3/2,1/2 -2s2p 6 2 S 1/2 lines which have recently found theoretical interest [32,33] and are discussed for elements Ar to Ca in [30]. An interesting point here is the line intensity ratio.…”

“…The beam-foil measurement technique has been recalled in various reviews (see [61,62] and references therein) and in two recent companion papers [30,31]. The spectra shown in this study have been obtained at the Bochum Dynamitron tandem accelerator laboratory (DTL), where a 4 MV tandem accelerator equipped with a sputter ion source [63,64] provided ion beams of more than 40 elements, with an energy from a few MeV up to about 30 MeV, and with beam currents (particle current) in the range from 0.1 µA to several µA of most iron group elements.…”

“…However, the latter technique provides isotopically pure spectra and thus can contribute to the analysis of coronal EUV spectra even if the spectral resolution is typically poorer than that of the spacecraft spectrographs. This contribution of data are one of the goals of the present study and its companions (on K and C [30], and on Sc, V, Cr, Mn, Co, Zn [31]) which together span the range of elements from Z = 19 to 30.…”

EUV Beam-Foil Spectra of Scandium, Vanadium, Chromium, Manganese, Cobalt, and Zinc

“…The beam-foil measurement technique has been recalled in a recent companion paper [44] and various reviews (see in [45,46] and references therein). The spectra shown in this study have been obtained at the Bochum Dynamitron tandem accelerator laboratory (DTL), where a 4 MV tandem accelerator equipped with a sputter ion source [47,48] provided ion beams of an energy between a few MeV up to about 30 MeV with beam currents (particle current) in the range from 0.01 µA to about 1 µA of the iron group elements.…”

“…A companion paper on K and Ca [44] has reported on a line ratio measurement in the F-like ion K XI, on the line doublet 2s 2 2p 5 2 P o 3/2,1/2 -2s2p 6 2 S 1/2 . The beam-foil line ratio in K XI agreed with the expected value calculated from the wavelengths of the two decay branches of the same upper level, or from computed transition rates A ki [7,11,16]), whereas the corresponding ratios observed in a low-pressure plasma discharge with Ar and Ca [52] did not.…”