Levels of 31P from [alpha]-particle capture in 27Al

Abstract

Resonance energies, strengths and decay schemes have been determined for seventeen 27Al(α, γ)31P resonances in the range Eα = 2.3–3.3 MeV. New levels of 31P are reported at Ex = 6503±3, 6792±3, 7117.7±1.0, 7441.4±1.0 and 8345.5±1.5 keV. The reaction Q-value is found as 9665.1 ±1.3 keV. Doppler-shift attenuation measurements lead to the mean lives τm, = 130±50, 300±80, 90±20, 90±50, 35±18, 220±90, 120±50, 17±14 and 39±10 fs for the 31P levels at Ex = 3.30, 3.41, 4.63, 4.78, 6.45, 6.79, 6.83, 7.44 and 8.35 MeV, respectively, and to eight upper and one lower limits for the mean lives of other levels. These lifetimes and the combined evidence of the decay of the resonance levels and bound states limit the possible Jπ values for many levels of 31P.