Measurements of isomeric cross sections for (n,2n) reaction on ¹⁴⁰Ce, ¹⁴²Nd and ¹⁴⁴Sm isotopes around 14 MeV

In this study, activation cross sections were measured for the ¹⁴⁰Ce(n,2n)^139mCe, ¹⁴²Nd(n,2n)^141mNd and ¹⁴⁴Sm(n,2n)^143mSm reactions at six different neutron energies from 13.5 and 14.8 MeV. The fast neutrons were produced via the ³H(d,n)⁴He reaction on SAMES T-400 neutron generator. The cyclic activation technique was used. Induced γ activities were measured by a high-resolution γ-ray spectrometer with a high-purity germanium (HpGe) detector. Corrections were made for the effects of γ-ray attenuation, dead-time and fluctuation of neutron flux. For these reactions, statistical model calculations for which the pre-equilibrium emission effects are taken into consideration were also performed between 13.6 and 14.8 MeV energy range. Theoretical excitation functions and experimental results were plotted together with previous works.