Structure of 22Mg, 26Si, 34Ar and 38Ca via the (3He, n) reaction

Proton-decaying states inMg22and the nucleosynthesis ofNa22<

“…We have carried out a measurement of the protondecay branching ratios of near-threshold states in 22 Mg. Populating the states via the (p, t) reaction in inverse kinematics with a 55 MeV/nucleon 24 Mg beam, we have detected tritons in coincidence with 22 Mg recoils and 21 Na decay products with 100% geometric efficiency. On the basis of the present and previous measurements, we assign spins and parities to the 5.96 MeV and 6.05 MeV levels.…”

“…The measurement was carried out at the Kernfysisch Versneller Instituut (KVI) using a recoil coincidence technique [7] through which we have detected both protonand γ-decaying recoils with 100% geometric efficiency in the Big-Bite Spectrometer [8]. A 55 MeV/nucleon 24 Mg beam provided by the variable energy, superconducting cyclotron AGOR bombarded a 1 mg cm −2 (CH 2 ) n target to populate states in 22 Mg via the (p, t) reaction in inverse kinematics. Both triton ejectiles and 22 Mg recoils entered the magnetic spectrometer, which was positioned at 0…”

“…The latest compilation [17] includes only a single level at 5965 (25) keV. The angular momentum and parity of this state were assigned as 0 + on the basis of angular distribution measurements using the ( 3 He,n) reaction [23,24]. In an early (p, t) measurement at 42 MeV [25], a peak was seen at 6.061(37) MeV that was assumed to be the same 0 + state observed in the ( 3 He,n) study at 5.945 (20) MeV.…”

A study of the proton resonant property in 22Mg by elastic scattering of 21Na + p and its astrophysical implication in the 18Ne(α, p)21Na reaction rate

“…20 Ne( 3 He, n) reaction [10,11] as well as the 20 Ne( 3 He, nγ) reaction [12,13]. By knowing the location of excitation states in 22 Mg, the resonance property of states just above the proton threshold has been studied by the direct 21 Na(p, γ) 22 Mg measurements [14,15] as well as by a resonant scattering measurement of 21 Na + p [16] with the DRAGON recoil separator at TRIUMF.…”

“…The resonant property of those states at E x = 10.12-11.13 MeV has been studied via the direct 18 Ne(α, p) 21 Na measurement [18,19], but the observed states are too high in energy for nucleosynthesis. As for the states above the α threshold, although their excitation energies were determined [7][8][9]11], their resonant properties (such as, J π , Γ α and Γ p ) have not been determined yet. Actually, in calculating the resonant reaction rate of 18 Ne(α, p) 21 Na using the narrow resonance formalism, the knowledge of the proton partial widths (Γ p ) is not required, since the resonance strength depends on the factor ΓαΓp Γtot and is based on the knowledge of the states in 22 Ne, Γ α ≪ Γ p ≈ Γ tot , so that ωγ = (2J + 1)Γ α , where J is the spin of the resonant states, and the partial width Γ α is given by 22 Ne α-transfer studies [21].…”