Prompt gamma rays emitted in thermal-neutron capture reaction by 99Tc and its reaction cross section

We have studied the primary and secondary gamma rays (a total of similar to1,100) in Tc-100 following thermal-neutron capture by the radioactive Tc-99 isotope. A fraction of these gamma rays have been incorporated into the corresponding level scheme consisting of 36 levels in Tc-100. The determined neutron separation energy (S-n) for Tc-100 is 6,765.20+/-10.04 keV. By Summing the cross sections of all ground-state transitions, we have obtained 21.37+/-0.68 b as a lower limit of the thermal-neutron capture cross section for Tc-99. We have also determined the capture cross section by examining the 540-and 591-keV gamma rays in (RU)-R-100 emitted following the beta(-) decay of Tc-100. The inferred thermal-neutron capture cross section for Tc-99 is 22.8 +/-1.8 b.