Hannover 2010 – scientific programme

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A: Fachverband Atomphysik

A 23: Poster II

A 23.19: Poster

Thursday, March 11, 2010, 16:30–19:00, Lichthof

Extreme-Ultraviolet Spectroscopy on highly charged Fe Ions in an EBIT — •Thomas Baumann, Guiyun Liang, José Crespo López-Urrutia, Hiro Tawara, and Joachim Ullrich — Max-Planck-Institut für Kernphysik, Heidelberg, Germany

Spectra in the extreme-ultraviolet range between 10 and 35 nm emitted from iron ions in charge states ranging from Fe VIII to Fe XXIV have been observed at the Heidelberg electron beam ion trap (EBIT). The emission spectra were recorded sequentially at electron beam energies from 75 eV up to 3 keV using a high precision flat-field grazing-incidence grating spectrometer.

The spectra clearly show the evolution of each ionic state as a function of the electron energy and, by comparison with collisional-radiative simulations, allow for line identification and separation of blends. Furthermore, the ion charge state distribution within the EBIT plasma could be determined from the relative line intensities. By comparing intensity ratios of emission lines from levels directly populated from the ground state to those starting from metastable levels of Fe XXI and Fe X, the effective electron densities within the plasma under different EBIT operation conditions were extracted.

Thus, EUV spectroscopic measurements serve as a precise tool for EBIT plasma diagnosis, and support solar observations by providing a laboratory technique for line identification.