Soft X-Ray Laser Spectroscopy on Trapped Highly Charged Ions at FLASH

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.

Major role of multielectronicK-Lintershell resonant recombination processes in Li- to O-like ions of Ar, Fe, and Kr

“…The variable bias acceleration voltage V DT pot is applied to all drift tubes, while keeping the ions trapped within a potential well of constant depth determined by the potential difference between the central drift tube and its immediate neighboring electrodes. We have used the FLASH-EBIT [17] for the Ar and Fe experiments and the Heidelberg EBIT [16] for the Kr measurements. The experimental procedure was the same in both devices.…”

“…In this paper we report in detail on our systematic high-resolution resonant recombination measurements performed at two of the EBITs at the Max-PlanckInstitut für Kernphysik in Heidelberg, Germany, namely, the HD-EBIT [16] and FLASH-EBIT [17]. We have extended the range of observed isoelectronic sequences, ranging now from He-like to O-like ions.…”

Guest Editor’s Notes on the “Atoms” Special Issue on “Perspectives of Atomic Physics with Trapped Highly Charged Ions”

“…In the vacuum ultraviolet (VUV), extreme ultraviolet (EUV), or X-ray range, however, there now are tunable light sources that can fill this role. The Heidelberg device FLASH-EBIT has been transported to the synchrotron light sources PETRA (at DESY Hamburg) [37] and BESSY-II (Berlin) [38], and to the free-electron lasers FLASH (at DESY Hamburg) [39,40] and LCLS (at SLAC, Menlo Park, CA) [41]. The electron beam ion trap was used to provide a target of highly charged ions of a known element and predictable highest charge state, and the narrowband VUV/EUV/X-ray radiation was scanned across a spectral band, resulting in detectable fluorescence only when in resonance with atomic transitions (usually ground state transitions) in the target.…”

Multiphoton ionization of atoms and ions by high-intensity X-ray lasers

“…In the nearest future, transition to a wavelength of 6 nm is planned and use will be made of the third and fifth harmonics of the fundamental fre quency (the latter harmonic corresponds to a wave length of 1.2 nm) [2]. Numerous experiments on the interaction of high intensity coherent rf radiation with atoms, molecules, multiply charged ions, nanostruc tures, and solids were performed at the DESY labora tory in 2002-2007 using free electron lasers (see [4][5][6][7][8][9] and the literature cited therein).…”

“…It can be seen from Table 1 that in the case of ion ization of atoms by the field of a titanium-sapphire laser, the adiabaticity parameter is not very large (γ ≈ 2-3) for reasonable values of intensity. 9 Accordingly, the deviation of the Coulomb correction from its tun nel limit (1), characterized by quantity Q 1 , is insignif icant (Q 1 ≈ 0.1; see Fig. 2 below).…”