Photoneutron cross section of in the giant dipole resonance region measured with quasimonoenergetic -rays at the Shanghai Laser Electron Gamma Source
Phys. Rev. C 114, 045810 – Published 19 October, 2026
DOI: https://doi.org/10.1103/rm6z-cgrb
Abstract
The photoneutron cross sections for the , reaction have been measured using quasimonoenergetic -ray beams at the Shanghai Laser Electron Gamma Source (SLEGS) in the energy range from 7.54 to 13.53 MeV. A flat-efficiency neutron detector consisting of 26 proportional counters was employed to minimize systematic uncertainties associated with neutron energy dependence. An iterative unfolding method was applied to extract monoenergetic cross sections from the measured data. The results resolve the longstanding discrepancy between the Lawrence Livermore and Saclay datasets, confirming the systematically higher Saclay values and revealing an 18% underestimation in the Livermore data at the giant dipole resonance peak. A Lorentzian fit to the combined data yields resonance parameters of 13.56 MeV for the centroid energy, 4.08 MeV for the width, and mb for the peak cross section. Using these constrained results, we calculate the stellar photodisintegration rate and the reverse neutron capture cross section, providing improved input for p-process nucleosynthesis simulations and accelerator-driven system design.
