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I am an experimental nuclear physicist working in the field of Nuclear Astrophysics.
As such I am studying nuclear reactions driving the energy generation of stars. I am especially interested in stellar explosions, like supernovae explosions, and the underlying nuclear reactions.
Compact and extremely dense supernovae remnants, like neutron stars, are excellent nuclear physics laboratories.


Accreting neutron stars, i.e. neutron stars in a binary system with another, relatively unevolved star with activated mass transfer through Roche-lobe overflow, are amongst the most fascinating stellar objects. Typically, in the outer part in the accretion disk, proton-rich conditions are found, while moving inwards, it is getting more and more neutron rich.
"Funny" structures evolve there (e.g. pastas and gnocchis), forming a new kind of neutron-dense matter. Moving even more inwards, densities and temperatures are getting so extreme, that possibly even a quark-gluon-plasma might be formed.

As a nuclear physicist who studies more "low-energy" phenomena, the outer part of the accreting neutron star is very attractive. It is a rich nuclear physics laboratory, involving very short-lived "exotic" radioactive nuclei. Fast nuclear reactions lead to a shift of accreted abundances from hydrogen and helium to much heavier elements, like Sn and Te.
I try to understand these processes using experiments and corresponding models. This involves a combination of different fields, from pure nuclear structure to nuclear reactions and their correlations, from 1D symmetric stellar models to multi-D convective models, from complex nuclear experiments to so-far inaccessible isotopes, and so on.

We restage the processes happening in stars when studying reactions in terrestrial nuclear physics laboratories, like the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, the National Superconducting Cyclotron Laboratory in Michigan, USA, the RIKEN facility in Japan, and many other facilities all around the globe. Depending on what information is needed, I use variable experimental approaches to gain access to the particular reaction studied.
Typically, we use direct or indirect methods to constrain astrophysical relevant reactions. This involves experiments with γ-rays, protons, neutrons, heavy ions and other probes, combined with complex state-of-the-art experimental setups. Besides extracting highly exciting physics, this also heavily relies on new instrumental developments. Detectors provide the basic tools for us to measure and extract important properties, and so, we constantly try to improve and develop our detector systems.

Recently, I extended my interests to the "newly re"-discovered i(ntermediate) neutron process, which might take place in the late stages of the evolution of a post-AGB star during the Very Late Thermal Pulse (and assumably also on rapidly accreting white dwarfs?). The neutron densities reached are in between the slow neutron-capture process and still significantly below the rapid neutron-capture process conditions. This drives material neutron-rich; just into a region, which is, regarding the nuclear reaction rates, accessible with statistical approaches (Hauser-Feshbach rates), but also, for some reactions, single neutron resonances or direct capture dominate. As such, it is experimentally challenging and attractive, since new experimental methods need to be developed and tested. This also requires substantial theoretical nuclear structure developments.

I am also interested in the underlying stellar models. The very versatile stellar evolution code MESA (Modules for Experiments in Stellar Astrophysics) is an example of an open-source code with a huge user community and many interesting features. In the most recent instrumentation paper the authors describe first steps towards a reliable simulation of binary systems, including type I x-ray bursts. This is, of course, really exciting and a great tool to study nuclear physics on accreting neutron stars. I participated in the MESA summer school 2013 to learn and study the code, and in the near future, I want to make use of the capabilities provided with the newest releases.

Please see my short review article, published as a conference proceeding, for more information. Please also do not hesitate contacting me (see here for details).

Latest News
April 18, 2017

Our paper on the low-lying level structure of 56Cu measured with the GRETINA array at NSCL has been accepted for publication in Physical Review C. Here is the arXiv link: arXiv:1704.07941.

June 16, 2015

Beginning from today I started to work at the Goethe-University in Frankfurt a. M., Germany, in the group of Prof. Dr. Rene Reifarth. Please contact me as shown under Contact.

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