Nuclear Data Sheets for A = 34

Nica, N.; Singh, Balraj

doi:10.1016/j.nds.2012.06.001

Cited by 51 publications

(62 citation statements)

References 304 publications

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“…The excitation energy of the first 2 + state of 38 S is 1292 keV [55] and this suggests that a particle-core coupling description is appropriate for the 1517-keV J π = (11/2 − ) state of 39 S. in relation to the odd-A isotopes is rather sparse. The data presented in the figure were taken from Nuclear Data Sheet references [49,52,[55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72]. For the isotopes of sulfur and argon, the figure shows a good correlation between the behavior of the excitation energy of the first 2 + states of the even-A isotopes and the excitation energy differences of the first 11/2 − and first 7/2 − states of the odd-A isotopes with neutron number.…”

Section: Resultsmentioning

confidence: 85%

First in-beamγ-ray study of the level structure of neutron-richS39

et al. 2016

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The neutron-rich 39 S nucleus has been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of 36 S ions with a thin 208 Pb target. The magnetic spectrometer, PRISMA, and the γ -ray array, CLARA, were used in the measurements. Gamma-ray transitions of the following energies were observed: 339, 398, 466, 705, 1517, 1656, and 1724 keV. Five of the observed transitions have been tentatively assigned to the decay of excited states with spins up to (11/2 − ). The results of a state-of-the-art shell-model calculation of the level scheme of 39 S using the SDPF-U effective interaction are also presented. The systematic behavior of the excitation energy of the first 11/2 − states in the odd-A isotopes of sulfur and argon is discussed in relation to the excitation energy of the first excited 2 + states of the adjacent even-A isotopes. The states of 39 S that have the components in their wave functions corresponding to three neutrons in the 1f 7/2 orbital outside the N = 20 core have also been discussed within the context of the 0 ω shell-model calculations presented here.

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Section: Resultsmentioning

confidence: 85%

First in-beamγ-ray study of the level structure of neutron-richS39

et al. 2016

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“…Only tentative assignments exist for two of the three exceptions, at E x = 5578 and 5806 keV [27]. The third exception, at 4942 keV, is a known 1 + state; we prefer a transition with L = 1, leading to an assignment with negative parity for this state.…”

Section: Spectroscopy Of 34 CLmentioning

confidence: 81%

“…deuteron radius-of-curvature to focal-plane position were obtained at each angle using this information, and these fits were then used to determine excitation energies for states in 34 Cl populated via the 33 S( 3 He,d) reaction. Clearly resolved, strongly populated states in 34 Cl with energies known to ≤ 1.5 keV [25,27] (and in agreement with those energies determined through the 25 Al calibration) were then used as part of an internal calibration at each angle to finally determine the energies of states in 34 Cl. Table 1 lists excitation energies determined in the present work, along with un- 34 Cl excitation energies (in keV) and the transferred orbital angular momentum L of calculated differential cross sections fit to the data.…”

Section: Previous Workmentioning

confidence: 92%

“…We note that the precision of measurements of these ratios in grains varies from ≈ 1% (for carbon, nitrogen and silicon isotopes [15]) to ≈ 10% (for sulphur isotopes [19]). As such, a more precise 33 S(p, γ ) 34 Cl rate is clearly needed to better constrain predictions of sulphur abundances in novae, so as to assess the utility of the 32 34 Cl between the proton-threshold and 5.43 MeV [25][26][27], but no experimental information exists for the corresponding resonance strengths. Parameterizations and statistical model calculations have also been used to determine this rate in the past [5,28,29].…”

Section: Introductionmentioning

confidence: 99%

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Isotopic 32 S/ 33 S ratio as a diagnostic of presolar grains from novae

et al. 2014

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Measurements of sulphur isotopes in presolar grains can help to identify the astrophysical sites in which these grains were formed. A more precise thermonuclear rate of the 33 S(p, γ ) 34 Cl reaction is required, however, to assess the diagnostic ability of sulphur isotopic ratios. We have studied the 33 S( 3 He,d) 34 Cl proton-transfer reaction at 25 MeV using a high-resolution quadrupole-dipole-dipole-dipole magnetic spectrograph. Deuteron spectra were measured at ten scattering angles between 10 • and 55 • . Twentyfour levels in 34 Cl over E x = 4.6-5.9 MeV were observed, including three levels for the first time. Proton spectroscopic factors were extracted for the first time for levels above the 33 S + p threshold, spanning the energy range required for calculations of the thermonuclear 33 S(p, γ ) 34 Cl rate in classical nova explosions. We have determined a new 33 S(p, γ ) 34 Cl rate using a Monte Carlo method and have performed new hydrodynamic nova simulations to determine the impact on nova nucleosynthesis of remaining nuclear physics uncertainties in the reaction rate. We find that these uncertainties lead to a factor of ≤ 5 variation in the 33 S(p, γ ) 34 Cl rate over typical nova peak temperatures, and variation in the ejected nova yields of S-Ca isotopes by ≤ 20%. In particular, the predicted 32 S/ 33 S ratio is 110-130 for the nova model considered, compared to 110-440 with previous rate uncertainties. As recent type II supernova models predict ratios of 130-200, the 32 S/ 33 S ratio may be used to distinguish between grains of nova and supernova origin.

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“…3(8) [3]) affects the production of 34 S, an important isotopic observable in pre-solar grains. A fast thermonuclear reaction rate leads to the destruction of 34 Cl and bypasses the production of 34 S, the beta decay * fry@nscl.msu.edu † wrede@nscl.msu.edu daughter of 34 Cl (t 1/2 =1.5266(4) s [4]). In an astrophysical reaction rate sensitivity study done by Iliadis et al, it was found that varying a statistical model rate by a factor of 100 up and down leads to a change in the final 34 S abundance by up to a factor of five [5].…”

Section: Introductionmentioning

confidence: 99%

Discovery of34g,mCl(p,γ)35Arresonances activated at classical nova temperatures

et al. 2015

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Background: The thermonuclear 34g,m Cl(p, γ) 35 Ar reaction rates are unknown due to a lack of experimental nuclear physics data. Uncertainties in these rates translate to uncertainties in 34 S production in models of classical novae on oxygen-neon white dwarfs.34 S abundances have the potential to aid in the classification of presolar grains.Purpose: Determine resonance energies for the 34g,m Cl(p, γ) 35 Ar reactions within the region of astrophyical interest for classical novae to a precision of a few keV as an essential first step toward constraining their thermonuclear reaction rates. Method:35 Ar excited states were populated by the 36 Ar(d, t) 35 Ar reaction at E(d)=22 MeV and reaction products were momentum analyzed by a high resolution quadrupole-dipole-dipole-dipole (Q3D) magnetic spectrograph. Results: Seventeen new35 Ar levels have been detected at a statistically significant level in the region Ex ≈ 5.9-6.7 MeV (Er < 800 keV) and their excitation energies have been determined to typical uncertainties of 3 keV. The uncertainties for five previously known levels have also been reduced substantially. The measured level density was compared to those calculated using the WBMB Hamiltonian within the sd − pf model space. Conclusions:Most of the resonances in the region of astrophyical interest have likely been discovered and their energies have been determined, but the resonance strengths are still unknown, and experimentally constraining the 34g,m Cl(p, γ) 35 Ar reaction rates will require further experiments.

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Nuclear Data Sheets for A = 34

Cited by 51 publications

References 304 publications

First in-beamγ-ray study of the level structure of neutron-richS39

First in-beamγ-ray study of the level structure of neutron-richS39

Isotopic 32 S/ 33 S ratio as a diagnostic of presolar grains from novae

Discovery of34g,mCl(p,γ)35Arresonances activated at classical nova temperatures

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