Cross section determination of 27Al(n,2n)26Al reaction induced by 14-MeV neutrons uniting with D-T neutron activation and AMS techniques

Aluminum is the primary structural material in nuclear engineering, and its cross section induced by 14-MeV neutrons is of great significance. To address the issue of insufficient accuracy for the \(^{27}\hbox {Al}\)(n,2n)\(^{26}\hbox {Al}\) reaction cross section, the activation method and accelerator mass spectrometry (AMS) technique were used to determine the \(^{27}\hbox {Al}\)(n,2n)\(^{26}\hbox {Al}\) cross section, which could be used as a D-T plasma ion temperature monitor in fusion reactors. At the China Academy of Engineering Physics, neutron activation was performed using a K-400 neutron generator produced by the T(d,n)\(^{4}\hbox {He}\) reaction. The \(^{26}\hbox {Al}/^{27}\hbox {Al}\) isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry, Chinese Academy of Sciences. The neutron flux was monitored by measuring the activity of \(^{\mathrm{92\,m}}\hbox {Nb}\) produced by the \(^{93}\hbox {Nb}\)(n,2n)\(^{\mathrm{92\,m}}\hbox {Nb}\) reaction. The measured results were compared with available data in the experimental nuclear reaction database, and the measured values showed a reasonable degree of consistency with partially available literature data. The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence, which has two different growth trends from the existing experimental values. The obtained results are also compared with the corresponding evaluated database, and the newly calculated excitation functions with TALYS\(-\)1.95 and EMPIRE\(-\)3.2 codes, the agreement with CENDL\(-\)3.2, TENDL-2021 and EMPIRE\(-\)3.2 results are generally acceptable. A substantial improvement in the knowledge of the \(^{27}\hbox {Al}\)(n,2n)\(^{26}\hbox {Al}\) reaction excitation function was obtained in the present work, which will lay the foundation for the diagnosis of the fusion ion temperature, testing of the nuclear physics model, evaluation of nuclear data, etc.