The reaction 26Mg(p, γ)27Al : (I). Excitation energies and branching of 27Al levels

Abstract

The gamma-ray spectra of thirty 26Mg(p, γ)27Al resonances in the range Ep = 0.3−2.8 MeV, were measured with a 20 cm3 Ge(Li) detector. Internal calibration based only on the reaction Q-value and the 511 keV annihilation line, leads to level energies with a precision ranging from a few tenths of a keV for the lower levels to 2 or 3 keV for the higher levels. Branching ratios are reported for the thirty resonance levels and most of the known bound states. A remarkable grouping of resonances which strongly decay to highly excited (Ex6–7 MeV bound states suggests some form of intermediate structure even at the widely spaced low-energy resonances; it can be described only partly in terms of isobaric analogue states.