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Experimental study of {beta}-delayed proton decay of {sup 23}Al for nucleosynthesis in novae

Journal Article · · Physical Review. C, Nuclear Physics
;  [1]; ; ; ; ; ; ; ; ;  [2];  [3]; ;  [4]
  1. Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), FI-40014 Finland (Finland)
  2. Cyclotron Institute, Texas A and M University, College Station, Texas 77843-3366 (United States)
  3. Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)
  4. School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom)
The {beta}-delayed {gamma} and proton decay of {sup 23}Al has been studied with an alternative detector setup at the focal plane of the momentum achromat recoil separator MARS at Texas A and M University. We could detect protons down to an energy of 200 keV and determine the corresponding branching ratios. Contrary to results of previous {beta}-decay studies, no strong proton intensity from the decay of the isobaric analog state (IAS) of the {sup 23}Al ground state at E{sub x}=7803 keV in {sup 23}Mg was observed. Instead we assign the observed low-energy group E{sub p,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 E{sub x}=7787 keV in {sup 23}Mg, which is a very rare case in the literature. Combining our data with its measured lifetime, we determine its resonance strength to be {omega}{gamma}=1.4{sub -0.4}{sup +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 {sup 22}Na(p,{gamma}){sup 23}Mg in some astrophysical environments, such as novae.
OSTI ID:
21499634
Journal Information:
Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 4 Vol. 83; ISSN 0556-2813; ISSN PRVCAN
Country of Publication:
United States
Language:
English