Disintegration of Iron-52 and Iron-53

Abstract

The disintegration of ${\mathrm{Fe}}^{52}$(8.2 hours) and ${\mathrm{Fe}}^{53}$(8.9 min) has been investigated with the help of scintillation and coincidence counting equipment. ${\mathrm{Fe}}^{52}$ decays 56.5% by positron emission and 43.5% by electron capture. The end-point energy of the positron group is 0.804\ifmmode\pm\else\textpm\fi{}0.01 Mev. This is followed by a gamma ray of energy 165 kev leading to ${\mathrm{Mn}}^{52m}$(21 min). The chain ${\mathrm{Fe}}^{52}$\ensuremath{\rightarrow}${\mathrm{Mn}}^{52}$\ensuremath{\rightarrow}${\mathrm{Cr}}^{52}$ has been studied. In addition to the well-known states of ${\mathrm{Mn}}^{52}$---the ground state, with character 6+ and half-life of 5.7 days, and the first excited state (${\mathrm{Mn}}^{52m}$), with character 2+, half-life of 21 min, and energy of 390 kev---these experiments show a third excited state at 555 kev having a configuration 0+ and a half-life of (1.2\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. The disintegration of ${\mathrm{Fe}}^{53}$ is accompanied by the emission of a gamma ray of energy 380 kev and positron groups of end-point energies 2.84\ifmmode\pm\else\textpm\fi{}0.10, 2.38\ifmmode\pm\else\textpm\fi{}0.10 Mev, and an indication of third group at 1.57\ifmmode\pm\else\textpm\fi{}0.15 Mev.