Seminarium Fizyki Jądra Atomowego

The determination of the carbon-to-oxygen ratio produced during the final stages of helium burning in stars poses a significant challenge in astrophysics. The thermonuclear reactions that regulate the ratio occur at energies far below the Coulomb barrier, making direct measurements not possible at the relevant energies. Consequently the astrophysical S-factor at the Gamow peak needs to be extrapolated from data at higher energies, which are still very challenging experimentally and affected by large uncertainties. High-intensity γ-ray beams provide a new opportunity to investigate the 12C(α,γ)16O reaction, i.e. the key that regulates carbon-to-oxygen ratios in the Universe, via time-reversal photo-disintegration, offering advantages over previous methods. The Warsaw TPC, an active-target Time Projection Chamber with electronic readout, was developed at the University of Warsaw for comprehensive studies of nuclear reactions with high-intensity γ-ray beams. In 2022, it was deployed at the HIγS facility for measurements focusing on the photo-disintegration of 16O and 12C using monochromatic γ-ray beams. This seminar will cover the detector design, experiment principles and preliminary results.