Search for Supernova R-process Actinides in Fossilized Reservoirs
Even though GW170817 and the associated kilonova from a neutron-star merger were detected in August 2017, the possible sites of r-process elements remain an open question in nuclear astrophysics, including special kinds of core-collapse supernovae (CCSNe). A well-known supernova-produced 60Fe radioisotope has been found in several terrestrial reservoirs proving that material from the ejecta of a nearby supernova arrived on earth in the last several millions of years. If live r-process isotopes were to be found in temporal coincidence with the 60Fe peak, it would provide strong evidence to the r-process occurring in CCSNe. The radioisotope 244Pu has been chosen, as it is an r-process only isotope and has a very long half-live, providing the same conditions as for 60Fe. Unfortunately, it is much less abundant than even 60Fe, and therefore a highly concentrated reservoir must be found. Candidates for this type of investigations were found in Atacama Desert, Chile, and Turkana Basin.
A great challenge that arises during the 244Pu investigations is the inherent anthropogenic contamination with Plutonium isotopes released during the atmospheric nuclear weapon tests. The AMS (Accelerator Mass Spectrometry) measurements and sample preparation were carried out using the 1MV Tandetron Accelerator installed at the RoAMS Laboratory at IFIN-HH, Romania.
Anthropogenic plutonium results obtained while investigating fossils from Turkana Basin and Atacama Desert will be presented along with data for certified reference materials and data on interstellar Pu-244.
Acknowledgements: This research was supported by the Collaborative Research Center SFB1258 of the Deutsche Forschungsgemeinschaft (SFB1258 – M06 Prof. Shawn Bishop), Romanian Government Program through the National Program for Installations of National Interest (IOSIN).
Iuliana Stanciu is a research assistant at the Horia-Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH) in Romania. She obtained her degree in Chemical Engineering in 2015 from the Polytechnical University of Bucharest, Romania while working in the radiocarbon dating laboratory at IFIN-HH. Iuliana completed her PhD in Experimental Nuclear Astrophysics at the Technical University of Munich (Germany) within the group of Prof. Shawn Bishop. Her work focused on searching for the r-process isotope - Pu244 in fossilized reservoirs using Accelerator Mass Spectrometry.