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A: Fachverband Atomphysik

A 15: Precision spectroscopy of atoms and ions III (with Q)

A 15.1: Hauptvortrag

Dienstag, 19. März 2013, 11:00–11:30, B 305

X-ray laser spectroscopy with trapped highly charged ions — •Sven Bernitt — Max-Planck-Institut für Kernphysik, Heidelberg, Germany

The X-ray spectra of many astrophysical objects, as observed by X-ray observatories like Chandra and XMM-Newton, are dominated by emission lines of highly charged ions. However, even today's most sophisticated spectral models only poorly fit certain prominent spectral features. For this reason, precise laboratory measurements of astrophysically relevant transition wavelengths and intensities are needed to be able to interpret astronomical observations.

Laser spectroscopy is a remarkably successful experimental method. However, the X-ray wavelength regime has not been accessible due to the lack of appropriate lasers, until in recent years free-electron lasers have become available. In the experiments presented, an electron beam ion trap was used to provide a target of trapped highly charged ions, interacting with femtosecond X-ray pulses from the Linac Coherent Light Source free-electron laser. This introduced the techniques of laser spectroscopy into the 1 keV spectral range, allowing to directly address photonic excitations in highly charged ions.

Results of an experiment, potentially resolving a continuing controversy about the relative intensity ratio of two bright lines in the Fe XVII spectrum, will be presented, as well as new results and applications.