Radioactive Isotopes of Iron

Radioactive ${\mathrm{Fe}}^{59}$ has been produced through the reactions ${\mathrm{Fe}}^{58}(d, p){\mathrm{Fe}}^{59}$ and ${\mathrm{Co}}^{59}(n, p){\mathrm{Fe}}^{59}$; the half-life is 47±3 days. The emitted particles are negative electrons, most of which have a range of 0.09 grams/${\mathrm{cm}}^2$ Al, while a small number extend to 0.35 grams/${\mathrm{cm}}^2$ Al. The gamma-ray shows a half-thickness of 10 grams/${\mathrm{cm}}^2$ Pb. Radioactive ${\mathrm{Fe}}^{53}$ is formed by the two processes ${\mathrm{Fe}}^{54}(n, 2n){\mathrm{Fe}}^{53}$ and ${\mathrm{Cr}}^{50}(\alpha , n){\mathrm{Fe}}^{53}$; positrons are ejected with a half-life of 8.9±0.2 minutes. No subsequent decay of ${\mathrm{Mn}}^{53}$ to ${\mathrm{Cr}}^{53}$ has been observed. No activity corresponding to ${\mathrm{Fe}}^{55}$ has been detected, although Cr, Mn, Fe, Co and Ni have been bombarded with protons, neutrons, deuterons and alpha-particles in all the combinations that might be expected to produce this isotope; it is concluded that ${\mathrm{Fe}}^{55}$ is either stable or has a very long or a very short life.