Cross section measurements via residual nuclear decays: Analysis methods

We develop an approach to calculating the pure cross section of the ground state of artificial radioactive nuclides that subtracts the effect of an excited state on the ground state. We apply a formalism to obtaining pure cross sections by subtracting the effect of excited states in the reactions 122Te(n,2n)121Teg and 128Te(n,2n)127Teg, induced by neutrons of about 14 MeV. The cross sections are measured by an activation relative to the 93Nb(n,2n)92Nbm reaction and are compared with results that take into account the effect of the excited state. Measurements are carried out by γ detection using a coaxial high-purity germanium (HPGe) detector. As samples, spectroscopically pure Te powder is used. The fast neutrons are produced by the 3H(d,n)4He reaction. The neutron energies in these measurements are determined using the method of cross-section ratios between the 90Zr(n,2n)89Zrm+g and 93Nb(n,2n)92Nbm reactions.