Neutron capture reaction cross section measurement for iodine nucleus with detailed uncertainty quantification

The neutron activation cross section for $$^{127}$$ I(n, $$\gamma $$ ) $$^{128}$$ I reaction has been experimentally measured with respect to the $$^{115}$$ In(n,inl) $$^{115}$$ In $$^{m}$$ reference monitor reaction cross section in the neutron spectrum average energy range 0.60 $$--$$ 2.51 MeV. The neutrons were produced through $$^{7}$$ Li(p,n) $$^{7}$$ Be reaction, and $$\gamma $$ -ray spectra of the residue product were measured offline with the precalibrated lead-shielded HPGe detector. The very first time the covariance analysis was done to quantify the measured cross section uncertainties and the correlation coefficients between the different neutron energy cross sections for iodine nucleus. The needful corrections related to the $$\gamma $$ -ray self-attenuation process, $$\gamma $$ -ray true coincidence summing effect and the low background neutron energy contributions were considered in the present measurement. Theoretical calculations were done using the standard nuclear reaction model codes TALYS-1.9 and EMPIRE-3.2 to obtain the $$^{127}$$ I(n, $$\gamma $$ ) $$^{128}$$ I reaction cross section. The measured cross sections were compared with the experimental data available in the EXFOR database, theoretical predicted results, and ENDF/B-VIII.0, JEFF-3.1/A, TENDL-2019, and JENDL-4.0 evaluated nuclear data.