Measurement of Co 59 ( γ , n ) Co 58 using a new flat-efficiency neutron detector at the Shanghai Laser Electron Gamma Source

The $(\ensuremath{\gamma},n)$ cross sections for the $^{59}\mathrm{Co}$ isotope within the range of giant dipole resonance were measured using laser Compton scattering (LCS) $\ensuremath{\gamma}$ rays at the Shanghai Laser Electron Gamma Source (SLEGS), Shanghai Synchrotron Radiation Facility (SSRF). A new neutron flat efficiency detector (FED) array was employed for neutron detection, and a BGO detector with 100% efficiency was utilized to precisely determine the energy distribution of the LCS radiation. The incident energy of $\ensuremath{\gamma}$ was adjusted from ${E}_{\ensuremath{\gamma}}=10.52\phantom{\rule{0.28em}{0ex}}\mathrm{MeV}$ to 18.95 MeV by adjusting the collision angles of the laser to the electron beam in the SSRF storage ring and compared with the experimental data and the TENDL-2023 evaluated data. The experimental results are significantly different from those of the Livermore and other bremsstrahlung-generated $\ensuremath{\gamma}$ source, but better agree with those measured by the LCS $\ensuremath{\gamma}$ source. The measurement data were used as experimental constraint to extract the gamma strength function $(\ensuremath{\gamma}\mathrm{SF})$, and the inverse reaction cross section of $^{58}\mathrm{Co}(n,$ $\ensuremath{\gamma})$ was subsequently calculated.