Atomic Polarization Spectroscopy: working group of PD Dr. Stanislav Tashenov
Our young investigators group is funded by DFG within the Emmy Noether program to study fundamental processes of photon-matter interaction in the realm of hard x-rays and heavy atomic systems. In particular we study the processes of radiative and dielectronic recombination (inverse photoelectric and Auger effects) and bremsstrahlung. We investigate their alignment and polarization properties. Such properties, so far rarely studied, reveal the finest details of the coupling of light to matter in the relativistic regime and in strong Coulomb fields.
We perform experiments using electron beam ion traps in Max-Planck-Institute for nuclear physics in Heidelberg, heavy ion storage ring in GSI Darmstadt and electron accelerators S-DALINAC in TU-Darmsatd and MAMI in Mainz University. To make such experiments possible we develop novel hard x-ray and gamma-ray polarimeters as well as new imaging and photon-photon correlation techniques in this high energy regime.
Apart from the fundamental importance, the investigated processes play an important role in fusion plasmas and hot astrophysical plasmas, such as those found near black holes. Our research establishes a basis for polarization diagnostics of such plasmas. We tested such techniques using a hot plasma in an electron cyclotron ion trap in the University of Paris 6. Furthermore, we developed techniques of polarimetry of relativistic beams of electrons and heavy ions. With these developments we work towards a completely new class of experiments - the experiments to investigate the parity violation in heavy ions and test the predictions of the Standard Model of particles and interactions in the atomic sector.
Polarization measurement of dielectronic recombination transitions in highly charged krypton ions
C. Shah, et al., Physical Review A 92, 042702 (2015)
Linear polarization of x-ray transitions due to dielectronic recombination in highly charged ions
Joerg, H. et al., Physical Review A 91, 042705 (2015)
Observation of coherence in the time-reversed relativistic photoelectric effect
S. Tashenov, et al., Physical Review Letters 113, 113001 (2014)
Measurement of the correlation between electron spin and photon linear polarization in atomic-field bremsstrahlung
S. Tashenov, et al., Physical Review Letters 107, 173201 (2011)
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