Neutron Total Cross Sections of Chromium and Iron in the kev Region

Abstract

The neutron total cross sections of chromium and iron have been measured in the energy range from one to 410 kev using neutron energy spreads from about 0.3 to 0.7 kev. Variations in the cross section of chromium show the presence of many resonances; seven of them in the region between 3 and 11 kev are due to neutron reactions with ${\mathrm{Cr}}^{53}$, and many others at higher energies are attributable to ${\mathrm{Cr}}^{53}$ and other less abundant isotopes. Eleven resonances are due to $s$-wave neutron reactions with ${\mathrm{Cr}}^{52}$. The results are similar for iron. Fourteen, or possibly fifteen, resonances are due to $s$-wave neutron reactions with ${\mathrm{Fe}}^{56}$. The values of the strength function of ${\mathrm{Cr}}^{52}$ and ${\mathrm{Fe}}^{56}$ for a well depth of approximately 40 Mev are 1.3 and 1.5×${10}^{-4\mathrm{}}$, respectively, and for ${\mathrm{Cr}}^{53}$ it appears to be much higher. A new technique for analysis of $s$-wave neutron scattering resonances has been developed.