本项目以兰州大学ZF-400型、中国工程物理研究院Pd-300或K-400型中子发生器为实验平台，通过d-T中子活化天然稳定同位素54-Fe、76-Ge、74-Se、85-Rb、87-Rb、110-Pd、115-In、114-Sn、123-Sb、122-Te、134-Ba、134-Ba、180-W、185-Re、196-Hg和198-Hg，并用高分辨率高纯锗探测器对其(n,2n)反应生成核同质异能态和基态的活度进行测量。根据生成核的衰变规律，扣除同质异能态对基态活度的影响，从而对生成核为纯基态的(n,2n)核反应截面进行系统的实验研究，目的是要得到其纯基态及其同质异能态与基态的截面比值。在实验测量的同时，结合Empire-II和Talys理论程序对其激发函数和截面比进行计算并评价，与文献中已有的数据进行比对，分析比对结果，对于有分歧的数据，找出数据分歧的原因，并对其进行矫正。

In this project, the pure ground-state cross sections and isomeric cross section ratios for the (n,2n) reactions on 54-Fe, 76-Ge, 74-Se, 85-Rb, 87-Rb, 110-Pd, 115-In, 114-Sn, 123-Sb, 122-Te, 134-Ba, 134-Ba, 180-W, 185-Re, 196-Hg and 198-Hg will be measured in the neutron energy range of 13.5-14.8 MeV using the activation technique. The fast neutrons are produced via the T(d,n)4He reaction on ZF-400 Intense Neutron Generator at Lanzhou University or Pd-300 or K-400 Neutron Generator at Chinese Academy of Engineering Physics (CAEP). Induced gamma activities are measured by a high-resolution gamma-ray spectrometer with high-purity germanium (HPGe) detector. According to the regulation of the growth and decay of an artificial radioactive nuclide, cross sections for the (n,2n) reactions with effect of an isomeric state on the ground-state will be systematic studied. The goal is to measure and obtain the pure ground-state cross sections and isomeric cross section ratios for the (n,2n) reactions on above nuclide. Meanwhile, nuclear model calculations using the code Empire-II and Talys, which employs the Hauser-Feshbach (statistical model) and exciton model (precompound effects) formalisms, are undertaken to describe the formation of the products. The ground-state cross sections and isomeric cross section ratios for reactions induced by neutrons on natural 54-Fe, 76-Ge, 74-Se, 85-Rb, 87-Rb, 110-Pd, 115-In, 114-Sn, 123-Sb, 122-Te, 134-Ba, 134-Ba, 180-W, 185-Re, 196-Hg and 198-Hg will be compared with experimental data found in the literature, and with values of model calculations, to analyse comparable results, to find out the cause of disagreement in those data, and also to correct the discrepant data.