Newsletter February 2013
X-ray detectors based on micro-calorimeter technology combine the broad bandwidth of standard solid-state x-ray detectors with a very high resolution comparable to crystal spectrometers. While such detector systems will offer unique experimental possibilities at the future FAIR facility, the complexity of the detector design and operation requires detailed planning and close collaboration between detector developers and experimentalists.
On the 31st of January the first workshop on the application of micro-calorimeters within SPARC, the atomic physics research collaboration at FAIR, was held at HI-Jena. About 40 scientists from the universities of Jena, Frankfurt, Giessen and Paris as well as from EMMI, GSI and HI-Jena took part in the discussions. Besides the application of micro-calorimeters at FAIR, the workshop was also used to define a road map for the commissioning of the novel maXs calorimeter and very first test experiments.
Prof. Stephan Fritzsche joins HI-Jena and FSU
Since the beginning of this year, Dr. Stephan Fritzsche has joined the Helmholtz Institute and the Department of Physics and Astronomy of the Friedrich Schiller University as Professor for Theoretical Physics and, especially, for the theory of correlated quantum systems in intense fields. In the future, he and his group will strengthen the activities of the institute in the area of relativistic quantum dynamics and strong-field QED and will hence support ongoing research in x-ray science and polarimetry.
During the past years, Stephan Fritzsche has worked at Oulu University (Finland) and the Frankfurt Institute of Advanced Studies (FIAS) where his research was focused mainly on the structure and dynamics of finite quantum systems with applications in atomic, optical and nuclear physics. In this time, in particular, he and his group applied atomic many-body techniques and the density matrix theory for modeling the excitation, ionization and recombination dynamics of neutrals and multiply-charged ions in synchrotron and FEL radiation as well as in the presence of strong Coulomb fields. Several case studies on the quantum dynamics of ions and atoms helped explore, for example, the relativistic light-matter coupling and the role of higher multipoles of the radiation field (than the electric-dipole component) by analyzing the angular and polarization correlations of emitted photons and electrons. Such investigations are of great importance for future research at GSI/FAIR as well as DESY/XFEL.
When combined with highly-correlated quantum amplitudes, the density matrix theory appears to be very suitable also to understand explicitly timedependent phenomena, such as the ionization and radiation of matter in short-pulse and pump-probe scenarios. In the future, therefore, Stephan Fritzsche and his group plans to develop new (many-body) methods for describing the electron dynamics of ions, atoms and plasma in strong fields. Apart from a better qualitative insight into the mechanisms, emphasis will be placed on models with predictive power and that provide quantitative understanding of the underlying processes.
Current and future research interest of Fritzsche's group will therefore include:
- multi-photon ionization dynamics in intense FEL radiation
- auto-ionization of atomic and molecular systems after irradiation
- light-matter interactions and light scattering in strong Coulomb fields
- excitation and decay mechanisms in highly-charged ions
- structure and spectroscopy of heavy and radio-active isotopes as well as
- particle beams carrying quantized orbital angular momentum