Article

Soft X-ray laser spectroscopy on trapped highly charged ions at FLASH

Institut für Experimentalphysik, University of Hamburg, Hamburg, Hamburg, Germany
Physical Review Letters (Impact Factor: 7.51). 06/2007; 98(18):183001. DOI: 10.1103/PhysRevLett.98.183001
Source: PubMed

ABSTRACT In a proof-of-principle experiment, we demonstrate high-resolution resonant laser excitation in the soft x-ray region at 48.6 eV of the 2 (2)S(1/2) to 2 (2)P(1/2) transition of Li-like Fe23+ ions trapped in an electron beam ion trap by using ultrabrilliant light from Free Electron Laser in Hamburg (FLASH). High precision spectroscopic studies of highly charged ions at this and upcoming x-ray lasers with an expected accuracy gain up to a factor of a thousand, become possible with our technique, thus potentially yielding fundamental insights, e.g., into basic aspects of QED.

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    • "The experiments, which benefit from high integrated flux are, e.g., spectroscopy of highly charged ions and cold molecular ions, produced with low concentration in the ion traps [1] [2]; spectroscopy of low Z elements [3], and studies of low populated mass selected clusters [6]. High integrated photon flux is greatly appreciated by the photon-induced materials processing applications. "
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Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. 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The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear deformation is achieved. Laser spectroscopy provides the only mechanism for such studies in exotic systems and uniquely facilitates these studies in a model-independent manner. The accuracy of laser-spectroscopic-determined nuclear properties is very high. 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    Physical Review Letters 10/2007; 99(11):113001. DOI:10.1103/PHYSREVLETT.99.113001 · 7.51 Impact Factor
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