Research Group Wilfried Nörtershäuser
Experimental Atomic and Nuclear Physics with Radioactive Nuclides

Open Positions

We always look for new highly motivated members of our working group to perform laser spectroscopy experiments at TU Darmstadt, the storage rings and trap facilities at the GSI Helmholtz Centre for Heavy Ion Research, at ISOLDE/CERN and at Argonne (USA). We offer all stages of education from mini-research, bachelor and master thesis up to PhD contracts. Please contact any member of the working group if you are interested.

The presentation (in German) of “Attraktive Physik” in WS 21/22 can be found here: pdf, 4.1 MB (opens in new tab)

A list of the theses that have been successfully finished in our working group can be found here .

Bachelor Theses

You are interested, but require an explanation in English? Please contact us .

You are interested, but require an explanation in English? Please contact us .

You are interested, but require an explanation in English? Please contact us .

You are interested, but require an explanation in English? Please contact us .

Master Theses

You are interested, but require an explanation in English? Please contact us .

You are interested, but require an explanation in English? Please contact us .

You are interested, but require an explanation in English? Please contact us .

Doctoral Projects

Project: ALIVE

The candidate will work on a prototype development for high-voltage measurements using collinear laser spectroscopy for scientific and metrological applications. Such measurements are required for many scientific projects, e.g. at storage rings, ISOL facilities or at KATRIN for neutrino mass measurements. This research will be predominantly performed at the Collinear Apparatus for Laser Spectroscopy and Applied Sciences (COALA) at TU Darmstadt where we have already demonstrated an accuracy of 5 ppm [Metrologia 55, 268 (2018)], which is close to the world-best high-voltage dividers reaching 1 ppm. Further improvements in the collinear apparatus, i.e., the acceleration region and the ion source section are foreseen. The latter was recently equipped with an Electron Beam Ion Source (EBIS) to expand possible candidate ions to multiply charged species. With the available versatile laser systems that include titanium:sapphire laser, frequency doubling and quadrupling and optical frequency combs improved measurement schemes using Raman transitions for optical population transfer of a narrow velocity component [Phys. Rev. A 101, 052512 (2020)], can be applied. It is expected that realizing these ideas will further boost the accuracy beyond the systematical limitations of high-voltage dividers and provide a quantum standard for high voltages. Further widening of the research profile is possible by participating at experiments in the frame of FAIR Phase 0 experiments within the LASPEC or SPARC collaborations, e.g. at GSI, ANL, FRIB or ISOLDE.

Application: If you formally want to apply, please send a single pdf document including a letter of motivation, your CV, a transcript of your university grade records, and two contact addresses for letters of reference.

Contact: Prof. Dr. Wilfried Nörtershäuser (S2|14 410, ), Dr. Kristian König (S2|14 411, )

For the laser spectroscopy we use several tunable laser systems, including for example, pulsed lasers, single-mode ring Ti:Sa and dye lasers, frequency conversion and mixing units as well as frequency combs.

The candidate will work on laser spectroscopy of highly charged ions with the goal to test quantum electrodynamics in light and heavy isotopes. We are performing laser spectroscopy at the ESR and CRYRING storage rings at GSI/FAIR with the goal to develop optical pumping [Phys. Rev. Accel. Beams 24, 024701 (2021)], and to improve the sensitivity in laser spectroscopy of lithium-like heavy ions [Nat. Commun. 8, 15484 (2017)] by combining laser spectroscopy with dielectronic recombination (DR).
Polarization of an ion bean by optical pumping
At CRYRING, we have performed first tests of optical pumping using continuous wave (cw) lasers to polarized Mg+ ions and observed surprising results. We are presently getting the continuation of this experiment ready, which will take place in autumn 2023.
Getting granular on QED
In a beamtime at ESR, which took place in spring 2022, we were able to observe for the very first time the hyperfine transition of an artificially produced 208Bi82+ ion beam. A rigorous test of strong-field QED is now in reach by measuring the hyperfine transition in 208Bi80+. The preparation is just starting and a first attempt of this experiment is planned to take place early 2024.

Further widening of the research profile is possible by participating at collinear laser spectroscopy experiments in our other research areas at ANL, FRIB and at ISOLDE.

Application: If you formally want to apply, please send a single pdf document including a letter of motivation, your CV, a transcript of your university grade records, and two contact addresses for letters of reference.

Contact: Prof. Dr. Wilfried Nörtershäuser (S2|14 410, ), Dr. Rodolfo Sanchez (), Dr. Zoran Andelkovic (), Dr. Konstantin Mohr ()

The candidate will develop highly sensitive collinear laser spectroscopy techniques based on state-selective charge exchange and ionization with respect to applications at ISOLDE.. State-selective charge exchange will be used for measurements of 53,54Ca [J. Phys. G: Nucl. Part. Phys. 44, 044003 (2017)], while ionization measurements are foreseen for studies of fluorine isotopes and rare gases. For preparation measurements on stable isotopes, an offline ion source will be designed and implemented. The development work can be carried out at TU Darmstadt. Installation, commissioning and participation at various beamtimes will require extensive stays at ISOLDE/CERN. The distribution between TU Darmstadt and ISOLDE is subject to discussions and will also depend on the candidate’s personal preference. Further widening of the research profile is possible by participating at collinear laser spectroscopy beamtimes at other facilities, e.g. at ANL, FRIB and at the storage rings at GSI/FAIR.

Application: If you formally want to apply, please send a single pdf document including a letter of motivation, your CV, a transcript of your university grade records, and two contact addresses for letters of reference.

Contact: Prof. Dr. Wilfried Nörtershäuser (S2|14 410, ), Dr. Kristian König (S2|14 411, )

Project: BOR8 (ANL, Chicago)

The candidate will perform collinear laser spectroscopy on light isotopes. The isotope 8B is believed to be the prototype of a proton-halo nucleus, i.e. a core that is surrounded by a halo of a weakly bound proton. There are indications for this assumption from the measurement of its quadrupole moment but the most decisive measurement will be a direct nuclear charge radius measurement. We have already performed a measurement of the stable isotopes 10,11B using resonance ionization mass spectrometry on an atomic beam of boron [Phys. Rev. Lett. 122, 182501 (2019)]. At Argonne National Laboratory (ANL) we plan to perform collinear/anti-collinear measurements on a fast neutralized beam of 8B. Since the isotope is delivered after production attached to water molecules, a molecule breakup setup has been developed during the last years and has to be commissioned. The setup for collinear laser spectroscopy will be moved within the ANL from the CARIBU low-energy hall to the ATLAS facility, and a deep-UVl aser system based on a frequency quadrupled titanium:sapphire laser that is locked to a frequency comb has to be installed. Most of this work will be performed during extensive stays at ANL. Further widening of the research profile is possible by participating at collinear laser spectroscopy experiments in our other research areas at FRIB, GSI and ISOLDE.

Application: If you formally want to apply, please send a single pdf document including a letter of motivation, your CV, a transcript of your university grade records, and two contact addresses for letters of reference.

Contact: Prof. Dr. Wilfried Nörtershäuser (S2|14 410, ), Dr. Bernhard Maaß (ANL, )