Why Highly Charged Ions (HCI)
Ionized states of matter are of interest for questions in fundamental physics as well as for applications in other fields of physics and technology. More than 90% of matter in the universe appears in an ionized state. Almost all information in astronomy and astrophysics comes from radiation of electrons and ions. In tokamak-plasmas highly charged ions (HCI) occur as impurities and therefore it is important to know their properties. Photon emission spectra from highly charged ions are observed in the sun and other stars as well as in supernovae and even in comets passing close to the earth. Studies of the optical spectra give information of the elemental composition and the temperature of such objects.
The removal of electrons changes the atomic structure whereby inner electrons feel extremely strong electromagnetic fields with strengths that never can be achieved by conventional laboratory techniques. This allows studies of atomic properties in the ultra-relativistic regime thereby exploring the validity range of Quantum Electro-Dynamics (QED).

Investigations of optical to x-ray transitions in few-electron ions.
a. A soft X-ray emission (SXE) spectrometer will be directly connected to the S-EBIT to make high-resolution measurement of transitions in highly-charged ions, A determination of such transition energies would provide a challenge to many-particle effects and non-perturbative QED calculations. In addition to the Lamb-shift, the hyper-fine structure in few-electron systems can be measured, to get information on the distribution of nuclear magnetism.
b. XUV Free-Electron Laser (FEL) radiation interacting with HCIs in S-EBIT can be studied with FEL photon sources that have a brilliance 8-10 orders of magnitude larger than present synchrotron radiation sources. Combining the S-EBIT with an XUV-FEL will facilitate selective photon excitation of states in few-electron ions for the first time.
c. Laser-spectroscopy and lifetime measurements of metastable states in trapped highly charged ions. Metastable states can only decay by "forbidden transitions", which is the common name on all transitions that do not arise due to an electric dipole type coupling between an ion.

Highly-charge ions on surfaces and nano-capillaries:
Exploration of the low-emittance beam properties of S-EBIT by localizing HCI in a narrow area of about nm2 in a time as short as a few femtoseconds.. The interaction of HCI with solid surfaces offer unique conditions because the potential energy of the ion is very large, being for example 160 keV for 197Au69+ ions, corresponding to a power density of 1014 W/cm2. New types of investigations are possible due to the high yields of secondary electrons per HCI that allows to image the hit of every single ion. Beam focusing could be done by nano-tubes and nano-capillaries.
-Secondary ion mass spectrometry (SIMS)
-Single ion implantation
-Precision doping

Plasma spectroscopy from electron-ion processes is directly accessible through optical and x-ray windows at S-EBIT. Electron-ion collisions are abundant in plasmas, like those found in a fusion reactor or in the solar corona. To correctly model these plasmas it is essential to know the strength (rates and cross sections) of the various collision processes. Also from a fundamental point of view, recombination and ionization cross sections, as a function of electron energy, can be used to test theoretical models for the dynamical many-body problem at hand. One also gets e.g. very precise spectroscopic data on the level of testing Quantum Electro-Dynamical (QED) predictions for fundamental atomic systems.

Precision mass measurements in a Penning Trap The objective of the Penning trap mass spectrometer SMILETRAP is to perform high-precision measurements of stable atomic masses using the precision gain from highly charged ions. So far a mass uncertainty as low as 3×10-10 has been achieved in q/A doublet measurements for masses from A=1 up to A=202, with a loss of precision for the heavier ones. We plan mass measurements related to fundamental problems in physics with the objective to increase the mass precision by one order of magnitude. We aim at a precision below 10-10 over the full mass range. This will be achieved by increasing the charge state using S-EBIT, increasing the excitation time, cooling the ions and reducing systematic errors, as well as using Ramsey excitation.

Accelerator physics: There are plans to develop S-EBIT to a super-EBIT that should reach 250 keV electron beam energy. With that fully stripped Uranium ions could be obtained. One can also perform detector tests with energetic ions by exploiting the high charge of ions from S-EBIT for efficient acceleration. This mini-accelerator option can be used as multi-user facility for testing electronic devices and detectors.