New Isotope of Manganese; Cross Sections of the Iron Isotopes for 14.8-Mev Neutrons

Bombardment of iron enriched in ${\mathrm{Fe}}^{58}$ with 14.8-Mev neutrons produces an activity having a half-life of 1.1±0.1 min. On the basis of cross bombardments and the gamma-ray spectrum of the activity, this is assigned to ${\mathrm{Mn}}^{58}$. In addition, the following cross sections were measured: ${\mathrm{Fe}}^{58}(n, p)$, 23.0±3.5 mb; ${\mathrm{Fe}}^{57}(n, p)$, 71.0±7.0 mb; ${\mathrm{Fe}}^{56}(n, p)$, 128±13 mb; ${\mathrm{Fe}}^{58}(n, \alpha )$, 21.5±2.0 mb; ${\mathrm{Fe}}^{54}(n, \alpha )$, 270±135 mb; ${\mathrm{Fe}}^{57}(n, np)$, 6.1±2.6 mb; ${\mathrm{Fe}}^{54}(n, 2n)$, 7.9±0.8 mb; ${\mathrm{Fe}}^{54}(n, t)$, 0.6±0.1 mb.