Gamma-Rays fromMg26

The energies of the gamma-rays found in coincidence with the protons of the ${\mathrm{Na}}^{23}(\alpha , p){\mathrm{Mg}}^{26}$ reaction have been measured with a NaI(Tl) scintillation counter. The experiments revealed doubt as to the existence of an excited state at 0.4 Mev. A direct transition to ground was found from the 1.83-Mev excited state. Competition between a cascade transition to the 1.83-Mev excited state and a weaker crossover transition to ground was observed for the 2.97-Mev excited state. With the 3.97-Mev excited state were identified a cascade transition to the 1.83-Mev excited state and a probable crossover transition to the ground state. For the decay of the 4.35-Mev excited state, a 1.38-Mev transition to the 2.97-Mev excited state was established. There is also a discussion of possible spin and parity assignments and a few decay schemes proposed by the use of the Weisskopf lifetime formulas.