School Seminar Program
Stars, supernovae and meteorites: laboratory studies of nucleosynthesis using accelerator mass spectrometry
Dr. Anton Wallner
Department of Nuclear Physics
The complex isotopic signature of our solar system and that observed in stars can be understood as interplay between fundamental nuclear physics properties and the specific conditions of the stellar environment. Nuclear reactions shape the stellar evolution of stars and determine the different astronomical abundances. Accelerator mass spectrometry (AMS) represents a sensitive technique for studying such processes through ultra-low isotope ratio measurements while simulating stellar nucleosynthesis processes in the laboratory. In particular, for studying long-lived radionuclides such a technique yields much higher sensitivities when counting atoms directly rather than measuring decay products.
Two different applications utilizing AMS have been conducted:
(i) the search for live supernova-produced radionuclides in terrestrial archives, as well as trace element studies in nanodiamonds extracted from meteorites. Such studies probe directly specific nucleosynthesis sites and will help understanding heavy element nucleosynthesis in massive stars and dust formation from their ejecta;
(ii) the simulation of stellar nucleosynthesis processes in the laboratory via the study of dedicated nuclear reactions.
An overview on recent AMS measurements with respect to nuclear astrophysics will be given including a status report on the recently launched programme ‘Eurogenesis’, organized by the European Science Foundation.
Anton Wallner obtained his PhD in 2000 from the University of Vienna, Austria. His dissertation was on the production and diagnostic potential of long-lived 26Al in a fusion reactor. In 2000 he moved to Germany joining the Ludwig-Maximilian University and the Technical University Munich. There he continued AMS measurements in a wide range of applications. 2003 Anton Wallner moved to the University of Vienna leading the nuclear astrophysics programme at the VERA laboratory at the Faculty of Physics. 2010 he joined the Institute for Environmental Research at ANSTO, Sydney and in Oct. 2011 the Department of Nuclear Physics, RSPE-ANU. Current research interests include AMS applications in interdisciplinary topics ranging e.g. from nuclear (astro)physics to environmental studies and medical applications.
Refreshments will be held in the Tea Room after the Seminar (around 5pm)