Veranstaltungsarchiv

RS-APS-Seminar

Titel

RS-APS-Seminar

Beschreibung

From the abstract of the thesis presented:

The planned FAIR complex on the site of the GSI Helmholtz Center for Heavy Ion Research establishes a broad bandwidth of new experimental opportunities especially in the area of heavy ion physics. New efforts to not only use its high-energy storage ring HESR for proton—antiproton collisions, but also to open it up for experiments with relativistic heavy ions, are of great importance for the regime of relativistic collisions. They extend the options for atomic-physical studies into so far unreached areas of energy. This allows collision experiments of intensive, well-defined ion beams with virtually the full range of both energy and charge states with a variable gas target. Electrons and photons released in those interactions lead the way to detailed observations and analysis of atomic structures and processes within the collision system.

The planning of future experiments requires preferably pragmatic and precise methods of describing the cross sections of the most important interaction processes that lead to the emission of electrons and photons in ion—atom collisions. In the frame of this work a basic overview of relevant interaction processes of collisions in the new energy range made available beyond 500 MeV/u is summarized. Furthermore the theoretical description of their emission characteristics is collected from already existing work, and used to calculate the energy and angle differential cross-sections and polarization behaviors for a few processes in a wide range of parameters. The data sets are condensed into a database and compared to the results of other work, to test their quality. In the second part of this work the acquired data is used to plan a possible experiment at the HESR. For one, this demonstrates the practical usability of the database for future experiments. But also, the proposed experiment could be conducted in the initial phase of the storage ring’s operation. The functionality of the facility could be checked and the effect of negative-polarized X-ray radiation emitted by the radiative electron capture process, which – because of insufficient experimental capabilities – was not detectable yet, could be measured for the first time. Beyond the sole optimization of the experiment’s parameters using the database, several simulations were executed. The efficiency of a possible detector was studied, as well as the detectability of the effect itself under the precalculated experimental conditions. Secondly an analysis of the fraction of the radiation background was performed, that looked at the electrons which are also emitted and their interaction products with the experiment setup. The newly gained insight shows that a measurement of the negative polarization effect at the new storage ring seems possible, but new problems and challenges arise from the fact that the emitted particles carry much higher energies. For example, binary encounter electrons can reach kinetic energies in the MeV regime, which may lead to the emission of high energy secondary bremsstrahlung. This has to be considered when designing the new target chamber and detectors, and it is crucial for the planning of experiments to come.

Ort

Seminarraum HI-Jena, Fröbelstieg 3

Datum (Start der Veranstaltung)

11.02.2016