Berlin 2014 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 14: Poster: Precision spectroscopy of atoms and ions (with Q)

A 14.28: Poster

Montag, 17. März 2014, 16:30–18:30, Spree-Palais

X-ray laser spectroscopy with an electron beam ion trap at a free-electron laser — •Sven Bernitt and José Ramon Crespo López-Urrutia — Max-Planck-Institut für Kernphysik, Heidelberg, Germany

Highly charged ions (HCI) of various elements are found in the plasmas of many astrophysical objects. Ions of iron play a particularly important role, often dominating the X-ray spectra. High precision X-ray spectroscopy in the laboratory is necessary to test the underlying theory. With X-ray free-electron lasers now available, the techniques of laser spectroscopy can be applied in the X-ray region. By resonantly exciting transitions with photons it is possible to overcome many of the limitations of conventional spectroscopy with HCI, which used to rely on electron impact excitation. We present the results of experiments carried out at the Linac Coherent Light Source (LCLS) free-electron laser. An electron beam ion trap was used to produce and trap Fe¹³⁺, Fe¹⁴⁺, Fe¹⁵⁺, and Fe¹⁶⁺ and the fluorescence from resonantly excited transitions between 795 and 830 eV was detected. The relative oscillator strength of two prominent lines in Fe¹⁶⁺ provided new insight into a 40 year old enigma [1], and an until then only posulated line of Fe¹⁵⁺ was directly observed for the first time.
[1] S. Bernitt, Nature 492, 225 (2012).