Beta-delayed proton emission from 20Mg

Lund, M. V.; Andreyev, A. N.; Borge, María José García; Cederkäll, J.; Witte, H. De; Fraile, L. M.; Fynbo, H. O. U.; Greenlees, P. T.; Harkness-Brennan, L. J.; Howard, Alan; Huyse, M.; Jonson, B.; Judson, D. S.; Kirsebom, O. S.; Konki, J.; Kurcewicz, J.; Lazarus, I.; Lică, R.; Lindberg, Simon; Madurga, M.; Mărginean, N.; Mărginean, R.; Marroquín, I.; Mihai, C.; Münch, M.; Nácher, E.; Negreţ, A.; Nilsson, T.; Page, R. D.; Pascu, S.; Perea, Á.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Riisager, K.; Rotaru, F.; Sotty, Ch.; Stănoiu, M.; Tengblad, O.; Turturică, A.; Duppen, P. Van; Vedia, V.; Wadsworth, R.; Warr, N.

doi:10.1140/epja/i2016-16304-x

Cited by 17 publications

(52 citation statements)

References 28 publications

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“…The decay scheme presented in Figure 6 is deduced from the γ ray spectrum obtained in this experiment. Only the 19 Ne levels which are populated by 20 We proceed to discuss the individual 19 Ne states.…”

Section: Resultsmentioning

confidence: 99%

“…A. 19 Ne 1507 keV 5/2 − state There are two γ rays which are emitted from this state at 1232.5 keV and 1269.3 keV and they are expected 20 Mg(βp), and were determined by applying recoil corrections to the measured γ ray energies in the lab-frame (column-four). Column two reports the measured lifetimes of 19 Ne excited states.…”

Section: Resultsmentioning

confidence: 99%

“…A 1 µs timegate was also applied to reduce the contribution from random coincidences. The well known 984 keV γ ray from 20 Ne and 20 Mg(βpγ) 19 Ne peaks.…”

Section: B β Decay Detection Efficiencymentioning

confidence: 99%

“…The recoiling 19 Ne * is given an initial kinetic energy based on the CoM energy of the proton emission from an excited 20 Na state which is, to a good approximation, at rest in the plastic scintillator. The Monte Carlo simulation works by first assuming a lifetime for a 19 Ne * state and randomly sampling the exponential decay curve distribution.…”

Section: Doppler Broadening Analysismentioning

confidence: 99%

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Doppler broadening in Mg20(βpγ)Ne19 decay

et al. 2019

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Background: The 15 O(α, γ) 19 Ne bottleneck reaction in Type I x-ray bursts is the most important thermonuclear reaction rate to constrain experimentally, in order to improve the accuracy of burst light-curve simulations. A proposed technique to determine the thermonuclear rate of this reaction employs the 20 Mg(βpα) 15 O decay sequence. The key 15 O(α, γ) 19 Ne resonance at an excitation of 4.03 MeV is now known to be fed in 20 Mg(βpγ) 19 Ne; however, the energies of the protons feeding the 4.03 MeV state are unknown. Knowledge of the proton energies will facilitate future 20 Mg(βpα) 15 O measurements. Purpose: To determine the energy of the proton transition feeding the 4.03 MeV state in 19 Ne. Method: A fast beam of 20 Mg was implanted into a plastic scintillator, which was used to detect β particles. 16 high purity germanium detectors were used to detect γ rays emitted following βp decay. A Monte Carlo method was used to simulate the Doppler broadening of 19 Ne γ-ray lines and compare to the experimental data. Results: The center of mass energy between the proton and 19 Ne, feeding the 4.03 MeV state, is measured to be 1.21 +0.25 −0.22 MeV, corresponding to a 20 Na excitation energy of 7.44 +0.25 −0.22 MeV. Absolute feeding intensities and γ-decay branching ratios of 19 Ne states were determined including the 1615 keV state, which has not been observed before in this decay. A new γ decay branch from the 1536 keV state in 19 Ne to the ground state is reported. The lifetime of the 1507 keV state in 19 Ne is measured to be 4.3 +1.3 −1.1 ps resolving discrepancies in the literature. Conflicting 20 Mg(βp) decay schemes in published literature are clarified. Conclusions: The utility of this Doppler broadening technique to provide information on β-delayed nucleon emission and excited-state lifetimes has been further demonstrated. In particular, knowledge of the proton energies feeding the 4.03 MeV 19 Ne state in 20 Mg β decay will facilitate future measurements of the α-particle branching ratio.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…A 1 µs timegate was also applied to reduce the contribution from random coincidences. The well known 984 keV γ ray from 20 Ne and 20 Mg(βpγ) 19 Ne peaks.…”

Section: B β Decay Detection Efficiencymentioning

confidence: 99%

Section: Doppler Broadening Analysismentioning

confidence: 99%

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Doppler broadening in Mg20(βpγ)Ne19 decay

et al. 2019

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“…So far 2p-radioactivity has been observed in the decay of ground state 45 Fe [1,14], 54 Zn [15,16], 48 Ni [17,18], 67 Kr [19], 19 Mg [20], 30 Ar [21], 31 Ar * corresponding authors: Mamta Aggarwal, mamta.a4@gmail.com [22,23] 20 Mg [24,25,26], and excited states 22 Mg and 94 Ag (for 1p and 2p decay) [27,28] in experimental and theoretical [29,30] works have provided useful insights into this exotic decay mode of proton rich nuclei. Recent experimental observations of (i) β-delayed two-proton emission in the decay of 22 Si [31] (ii) 2p correlated emissions in 28,29 S but not in 27,28 P which indicated [8,9,10] that the diproton correlations may result from proton configuration in the initial state like 2p halo rather than the deformed orbit (iii) and the speculation [11] that the 2p halo plays an important role in the diproton emission, lack a precise theoretical description that has invoked the present study.…”

mentioning

confidence: 99%

Two-proton radioactivity with 2p halo in light mass nuclei A = 18–34

Saxena¹,

Kumawat

Kaushik³

et al. 2017

Physics Letters B

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Two-proton radioactivity with 2p halo is reported theoretically in light mass nuclei A = 18-34. We predict 19 Mg, 22 Si, 26 S, 30 Ar and 34 Ca as promising candidates of ground state 2p-radioactivity with S 2p < 0 and S p > 0. Observation of extended tail of spatial charge density distribution, larger charge radius and study of proton single particle states, Fermi energy and the wave functions indicate 2p halo like structure which supports direct 2p emission. The Coulomb and centrifugal barriers in experimentally identified 2p unbound 22 Si show a quasi-bound state that ensures enough life time for such experimental probes. Our predictions are in good accord with experimental and other theoretical data available so far.

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