Direct measurement of the 103Rh(n,γ) and 103Rh(γ,n) cross section up to stellar temperatures at the CSNS Back-n and SSRF SLEGS

The cross sections of 103 Rh(n, γ ) and 103 Rh( γ ,n) reactions play a crucial role in the stellar nucleosynthesis, rhodium-based self-powered neutron detectors, and nuclear medicine. The cross sections of 103 Rh(n, γ ) reaction was measured by the time-of-flight (TOF) method from 1 eV to 1000 keV at the Back-n facility of the Chinese Spallation Neutron Source. In the resolved resonance region, the data reported multiple new resonance structures for the first time. Several discrepancies, especially some previously spurious structures were clarified, offering valuable insights into the differences between the evaluated libraries. Maxwellian-averaged cross sections (MACSs) were calculated within the temperature range of the s process nucleosynthesis model, based on the averaged cross sections in the unresolved resonance region. Meanwhile the cross sections of 103 Rh( γ ,n) reaction within the range of p process nucleosynthesis were measured using laser Compton scattering (LCS) γ rays and a new neutron flat efficiency detector (FED) array at the Shanghai Laser Electron Gamma Source (SLEGS), Shanghai Synchrotron Radiation Facility (SSRF). Using an unfolding iteration method, 103 Rh( γ ,n) reaction data were obtained with uncertainty less than 5 %, and the inconsistencies between the available experimental data and the evaluated libraries were discussed. This study provides a reliable benchmark for nuclear data evaluation and model optimization, and lays a solid foundation for Rh medical isotope applications and astrophysical research.