Welcome and Introduction

• Konrad Schmidt (Helmholtz-Zentrum Dresden-Rossendorf, Germany)

Room: virtual

Russbach School on Nuclear Astrophysics

• Olivier Sorlin (Grand Accélérateur National d'Ions Lourds, France)

Room: virtual Introduction of the annual winter school and invitation to the Russbach School on Nuclear Astrophysics from March 13 to 19, 2022. https://events.hifis.net/e/russbach2022

Why to study stars underground?

• Rosanna Depalo (Università degli Studi di Milano, Italy)

Room: virtual First lecture

Moderated questions

• Konrad Schmidt (Helmholtz-Zentrum Dresden-Rossendorf, Germany)

Room: virtual

How to study stellar explosions with deep-sea sediments and ocean crust?

• Jenny Feige (Technische Universität Berlin, Germany)

Room: virtual Second lecture

Moderated questions

• Olivier Sorlin (Grand Accélérateur National d'Ions Lourds, France)

Room: virtual

Measurements of 3He(α,γ)7Be γ-ray angular distribution at Felsenkeller shallow underground laboratory

• Steffen Turkat (Technische Universität Dresden)

Room: virtual Scientific talk The 3He(α,γ)7Be reaction plays a significant role in Big Bang nucleosynthesis, as well as solar fusion processes. Furthermore it affects the predicted solar 7Be and 8B neutrino fluxes as well as the nucleosynthesis of primordial 7Li. A measurement of the angular distribution of the prompt gamma rays may enable a better comparison between several experimental data sets at E = 0.7 - 1.3 MeV and a unique data set from the LUNA collaboration at E = 0.09 MeV - 0.13 MeV. Therefore the 3He(α,γ)7Be reaction is currently being studied with the 5MV Pelletron accelerator at the Felsenkeller shallow underground facility. The long-term focus lies on the measurement of the gamma ray angular distribution between 0.5 and 1.3 MeV in center of mass. In addition to this inbeam-analysis, the activated 7Be samples are counted offline on a counting setup, which was recently installed underground. This setup contains a HPGe detector with a relative detection efficiency of 163% in a sophisticated shielding consisting of active and passive components. First results of this ongoing campaign will be summarized.

Moderated questions

• Marcel Heine (Hubert Curien Pluridisciplinary Institute, France)

Room: virtual

Single Atom Counting of Stellar and r-Process Nuclei in Time-Resolved Deep-Sea Archives

• Dominik Koll (Australian National University, Australia)

Room: virtual Scientific talk Stars are the major element factories in the universe. In 1999, live supernova Fe-60 (2.6 Myr half-life) was detected in a deep-sea ferromanganese crust indicating the accumulation of supernova dust on Earth about 2 million years ago. This was followed by several projects reinforcing the initial evidence for a global influx of supernova Fe-60. Recently, a much younger continuous influx was found in Antarctic snow and in deep-sea sediments and an older peak around 6 to 8 Myr in deep-sea crusts. In contrast to the well-known production mechanism and synthesis site of Fe-60, the long-lived plutonium isotope Pu-244 (80 Myr half-life) is a pure r-process nucleus. The nucleosynthesis site for the astrophysical r-process is still debated in the astrophysics community. Potential candidates involve rare supernovae and neutron star mergers. To date no evidence was presented that would point to an exclusive r-process site and combinations of different sites are considered. Experimentally, we can search for Pu-244 signatures in samples with known Fe-60 signatures to test for either common influx patterns or independent Pu-244 influxes disentangled from stellar Fe-60. Accordingly, this information provides a unique and direct experimental approach for identifying the production site of the heavy elements. Based on the recent publication of the first detection of interstellar Pu-244 in a ferromanganese crust with a time resolution of 4.5 Myr (integrating over much shorter Fe-60 influxes), we are now working on a highly time-resolved profile of Fe-60 and Pu-244 in the large ferromanganese crust VA13/237KD. This direct experimental input will further constrain models for r-process nucleosynthesis in the galaxy. The recently determined profile of Fe-60 clearly shows two influxes, one at 2 Myr, the other at 7 Myr, confirming and refining previous results. Preliminary data on Pu-244 and an outlook for future measurement campaigns will be given.

Moderated questions

• Livius Trache (Horia Hulubei National Institute for Physics & Nuclear Engineering, Romania)

Room: virtual

Round table discussion Room: virtual Questions that were compiled in the chat during and after lectures and breakout session will be answered and discussed.