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We present a new experiment on (quasi) symmetric collision systems at low velocity, namely Ar17+ ions (μ = 0.53 au) on gaseous Ar and N2 targets, using low- and high-resolution x-ray spectroscopy. Thanks to an accurate efficiency calibration of the spectrometers, we extract absolute x-ray emission cross sections combining low-resolution x-ray spectroscopy and a complete determination of the ion beam-gas jet target overlap. Values with improved uncertainty are found in agreement with previous results (Tawara et al 2001 Phys. Rev. A 64 042712). Resolving the whole He-like Ar16+ Lyman series from n = 2-10 with our crystal spectrometer enables us to determine precisely the distribution {Pn} of the electron capture probability and the preferential npref level of the selective single-electron capture. Evaluation of cross sections for this process as well as for the contribution of multiple-capture is carried out. Their sensitivity to the ℓ-distribution of n levels populated by single-electron capture is clearly demonstrated, providing a stringent benchmark for theories. In addition, the hardness ratio is extracted and the influence of the decay of the metastable 1s2s 3S1 state on this ratio is discussed. [ABSTRACT FROM AUTHOR]

We have performed a systematic study of the bremsstrahlung emission from the electrons in the plasma of a commercial 14.5 GHz electron-cyclotron resonance ion source. The electronic spectral temperature and the product of ionic and electronic densities of the plasma are measured by analyzing the bremsstrahlung spectra recorded for several rare gases (Ar, Kr, and Xe) as a function of the injected power. Within our uncertainty, we find an average temperature of ≈48 keV above 100 W, with a weak dependency on the injected power and gas composition. Charge state distributions of extracted ion beams have been determined as well, providing a way to disentangle the ionic density from the electronic density. Moreover x-ray emission from highly charged argon ions in the plasma has been observed with a high-resolution mosaic-crystal spectrometer, demonstrating the feasibility for high-precision measurements of transition energies of highly charged ions, in particular, of the magnetic dipole (M1) transition of He-like of argon ions. [ABSTRACT FROM AUTHOR]