Hyperfine Interact (2006) 173:13–18 DOI 10.1007/s10751-007-9536-1 Atomic spectroscopy of trapped, highly charged, heavy ions Elmar Träbert Published online: 20 June 2007 © Springer Science + Business Media B.V. 2007 Abstract For spectroscopy, the electron beam ion trap (EBIT) is of special interest, because it provides a cloud of highly charged ions that is confined to a small volume, at very low particle density, at a relatively low temperature, and without any net velocity in the laboratory rest frame. These conditions are favourable for observations at high spectral resolution and wavelength accuracy. Examples from recent work at Livermore comprise extreme ultraviolet and soft-X-ray spectra. A time-resolving multi-pixel microcalorimeter furthermore permits the study of time-dependent plasma phenomena and atomic lifetimes. Lifetime measurements at a heavy-ion storage ring can be combined with EBIT measurements to clarify isoelectronic behaviour. Keywords Visible and ultraviolet spectra · Lifetimes · Spectroscopic techniques 1 Introduction Quantum mechanics is the accepted framework in which atomic structure and processes can be described. A number of computer algorithms and program packages have been developed to put this description into practice. With the exception of some few-electron systems, experiment can describe atomic structure more precisely than calculations can – so far. In many cases it can be shown that quantum electrodynam- ical (QED) corrections can be computed to a higher precision than the experimental error bars. Hence the discrepancies between the results of precise experiments and E. Träbert (B ) Experimentalphysik III, Ruhr-Universität Bochum, 44780 Bochum, Germany e-mail: traebert@ep3.rub.de E. Träbert High Temperature and Astrophysics Division, Physics and Advanced Technologies, Lawrence Livermore National Laboratory, Livermore, CA 94550-9234, USA