β-Delayed proton-decay study of 20Mg and its implications for the Ne19(p,γ)Na

Studies of X-ray burst reactions with radioactive ion beams from RESOLUT

“…Some arguments favor a 1 + assignment for this state but with a small singleparticle component (see [24] for example). This is also supported an upper limit on the protoncapture resonance strength (ωγ < 16 meV) set from the a 19 Ne(p,γ) 20 Na reaction measurement [25]. However, some information argues otherwise.…”

“…Excitation energies are relatively well determined from charge-exchange reactions, but these studies have placed only weak constraints on J π values due to challenges from unresolved states and increased background above the separation energy, problems exacerbated by difficulties with neon targets [14][15][16]. Only the 3.00-MeV (1 + ) and 3.09-MeV (0 + ) states have clear assignments based upon 19 Ne+p elastic scattering [17] and their population in allowed β-decay transitions from 20 Mg [18,19]. These states have been identified as mirror levels to the 3.49-MeV and 3.53-MeV states in 20 F, with a large Coulomb shift resulting from a substantial 2s 1/2 component in the wavefunction as expected from sd shell model calculations.…”

“…Only the 2.966-MeV state in 20 F has majority sd single-particle character, being strongly populated in the 19 Most important is to determine the properties of the first state above the separation energy in 20 Na at 2.65 MeV that could dominate the 19 Ne(p,γ) 20 Na reaction rate given the low (E cm = 457 keV) resonance energy. Some arguments favor a 1 + assignment for this state but with a small singleparticle component (see [24] for example).…”

“…The rates of many of these reactions are purely theoretical or have large uncertainties due to experimental challenges in studying short-lived nuclei that hinder our understanding of X-ray bursts. e-mail: blackmon@lsu.edu Some of the important reactions in X-ray bursts are those that involve breakout of the hot-CNO cycle, either through the 17 F(p,γ) 18 Ne(α,p) 21 Na or 15 O(α,γ) 19 Ne(p,γ) 20 Na reaction sequences. We measured the 17 F(d,n) 18 Ne and 19 Ne(d,n) 20 Na reactions to improve our understanding of the 17 F(p,γ) 18 Ne and 19 Ne(p,γ) 20 Na capture reactions, respectively, that are important in breakout from the hot-CNO cycle.…”

“…Both measurements were conducted at the J. D. Fox Superconducting Accelerator Laboratory at Florida State University using "in-flight" radioactive ion beams. Stable beams of 16 O and 19 F bombarded a cryogenic gas cell to produce 17 F and 19 Ne from the 16 O(d,n) 17 F and 19 F(p,n) 19 Ne reactions, respectively. The radioactive products were collected and separated by the RESOLUT facility [5].…”