Experimental study of-delayed proton decay offor nucleosynthesis in novae
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The -delayed and proton decay of Al23 has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A&M University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous -decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the Al23 ground state at E x=7803 keV in Mg23 was observed. Instead we assign the observed low-energy group Ep,c.m.=206 keV to the decay from a state that is 16 keV below the IAS. We measured both proton and gamma branches from the decay of this state at Ex=7787 keV in Mg23, which is a very rare case in the literature. Combining our data with its measured lifetime, we determine its resonance strength to be =1.4-0.4+0.5 meV. The value is in agreement with older direct measurements, but disagrees with a recent direct measurement. This state is the most important resonance for the radiative proton capture Na22(p,)Mg23 in some astrophysical environments, such as novae. 2011 American Physical Society.
author list (cited authors)
Saastamoinen, A., Trache, L., Banu, A., Bentley, M. A., Davinson, T., Hardy, J. C., ... yst, J.
complete list of authors
Saastamoinen, A||Trache, L||Banu, A||Bentley, MA||Davinson, T||Hardy, JC||Iacob, VE||McCleskey, M||Roeder, BT||Simmons, E||Tabacaru, G||Tribble, RE||Woods, PJ||Äystö, J