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摘要
An accurate knowledge of the cross section for neutron-induced reactions on Co-59 is of importance clue to use of cobalt as a structural material in fission and fusion reactors, its applicability in neutron dosimetry and for testing theoretical models as well. The thin Co foils (0.25 mm thickness, 99.9% purity, Goodfellow product) were irradiated in the quasi-momoenergetic p-Li neutron field. For the production of the neutron fields, the proton beam from the NPI energy-variable cyclotron U120M at proton energies 19.8, 25.1, 27.6, 30.1, 32.7, 35.0 and 37.4 MeV and thin Li-7 target with carbon stopper were used. The reaction Li-7(p, n) produces the high-energy quasi-monoenergetic neutrons with tail to lower energies. The flux density and neutron spectra were evaluated by MCNPX code using Li-7(p,n) cross section measurement of other authors and including correction to the NPI target layout. The time profile of the neutron source strength during the irradiation was monitored by the proton beam current on the neutron-source target, recorded by a calibrated current-to-frequency converter on a PC. Au foils were used as additional monitors. The foil activity determination was performed by the nuclear spectrometry method employing two calibrated HPGe detectors of 23 and 50% efficiency and of FWHM (Full Width Half Maximum) 1.8 keV at 1.3 MeV for gamma-ray measurement. The reaction rates for (CO)-C-59(n, p) Fe-59, Co-59(n, alpha)Mn-56, Co-59(n, 2n alpha)Mn-54, Co-59(n, 3n)Co-57, Co-59(n, 2n)Co-58m and Co-59(n, 2n)Co-58g were obtained. Integral activation cross sections were estimated. The preliminary results are discussed.
- 出版日期2011-8-11
