The decay scheme of ${\mathrm{Co}}^{56}$ was studied by means of a magnetic lens spectrometer and a gamma-gamma coincidence scintillation spectrometer. The positron spectrum consists of two groups of maximum energies of 1.50 Mev and 0.44 Mev, relative abundance of 96 percent and 4 percent, respectively, leading to a second and third excited state of ${\mathrm{Fe}}^{56}$. Orbital electron capture also takes place involving several other excited states. Both of the beta-ray spectra involved appear to have the "allowed" shape of the Fermi plot. The energies of the gamma rays emitted by the ${\mathrm{Fe}}^{56}$ nucleus were determined by studies of the photoelectron spectrum and scintillation spectrum. The energies determined were 0.845 Mev, 1.24 Mev, 1.75 Mev, 2.30 Mev, 2.60 Mev, and 3.25 Mev, respectively. These gamma rays were fitted into the decay scheme by means of beta spectrum analysis and gamma-gamma coincidence experiments.

• Received 28 January 1954

DOI:https://doi.org/10.1103/PhysRev.95.101