Cross sections of theFe56(n,α)Cr53andFe54(n,α)Cr51reactions in the MeV region

Abstract

Cross sections of the $^{56}\mathrm{Fe}(n,\ensuremath{\alpha})\phantom{\rule{0.28em}{0ex}}^{53}\mathrm{Cr}$ and $^{54}\mathrm{Fe}(n,\ensuremath{\alpha})\phantom{\rule{0.28em}{0ex}}^{51}\mathrm{Cr}$ reactions were measured at ${E}_{n}=5.5\phantom{\rule{0.16em}{0ex}}\mathrm{and}\phantom{\rule{0.16em}{0ex}}6.5\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$ and ${E}_{n}=4.0,\phantom{\rule{0.16em}{0ex}}4.5,\phantom{\rule{0.16em}{0ex}}5.5,\phantom{\rule{0.16em}{0ex}}\mathrm{and}\phantom{\rule{0.16em}{0ex}}6.5\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}$, respectively, using a double-section gridded ionization chamber as the $\ensuremath{\alpha}$-particle detector. Natural iron and enriched $^{56}\mathrm{Fe}$ and $^{54}\mathrm{Fe}$ foil samples were prepared. A deuterium gas target was used to produce monoenergetic neutrons through the $^{2}\mathrm{H}(d,n)\phantom{\rule{0.28em}{0ex}}^{3}\mathrm{He}$ reaction. Two rounds of experiments were performed at the 4.5-MV Van de Graaff Accelerator of Peking University. The foreground and background were measured in separate runs. The neutron flux was monitored by a $\mathrm{B}{\mathrm{F}}_{3}$ long counter, and the cross sections of the $^{238}\mathrm{U}(n,f)$ reaction were used as the standard. Present results are compared with those of the talys-1.6 code calculations, existing measurements, and evaluations.