Spectroscopy of 24Al and extraction of Gamow-Teller strengths with the 24Mg(3He,t) reaction at 420 MeV

Abstract

The 24 Mg( 3 He,t) 24 Al reaction has been studied at E( 3 He) = 420 MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in 24 Al are extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small discrepancies for a few weak excitations, good agreement with previous 24 Mg(p, n) data and nuclear-structure calculations using the USDA/B interactions in the sd shell-model space is found. The excitation energy of several levels in 24 Al of significance for determination of the 23 Mg(p, γ) 24 Al thermonuclear reaction rate were measured. Results are consistent with two of the three previous ( 3 He,t) measurements, performed at much lower beam energies. However, a new state at Ex( 24 Al)=2.605(10) MeV was found and is the third state above the proton separation energy.