## Abstract

The present work demonstrates the feasibility of alining manganese-56 produced by neutron irradiation of a nickel fluosilicate crystal containing stable $^{55}$Mn. Measurements were made of the angular distribution of the $\gamma $-radiation from the alined $^{56}$Mn and also of the angular correlation of the $\gamma $-rays from this isotope. By combining the results it is possible to establish uniquely as 2 the spins of the states of the daughter nucleus of $^{56}$Fe at 2$\cdot $66 and 2$\cdot $98 MeV. The mixing ratios $\delta $(E 2/M 1) for the 1$\cdot $81 and 2$\cdot $13 MeV $\gamma $-rays to the first excited state are shown to be 0$\cdot $19 $\pm $ 0$\cdot $02 and - 0$\cdot $28 $\pm $ 0$\cdot $02. The spectrum of the $\gamma $-radiation was studied with a scintillation spectrometer and this leads to the following relative intensities; 0$\cdot $845 MeV (100%), 1$\cdot $81 MeV (27 $\pm $ 3%), 2$\cdot $13 MeV (15 $\pm $ 3%), 2$\cdot $55 MeV (1$\cdot $2 $\pm $ 0$\cdot $2%), 2$\cdot $66 MeV (0$\cdot $65 $\pm $ 0$\cdot $1%), 2$\cdot $98 MeV (0$\cdot $35 $\pm $ 0$\cdot $1%) and 3$\cdot $4 MeV (0$\cdot $22 $\pm $ 0$\cdot $05%). Coincidence measurements suggest that the 2$\cdot $55 and 3$\cdot $4 MeV $\gamma $-rays are due to de-excitation of a level at about 3$\cdot $4 MeV which decays both to the ground and first excited states. A spin of 2 for this state is proposed.

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