Energy measurements of proton resonances in light nuclei
Synopsis
A search has been made for (p, ) resonances in all stable nuclides from 19F through 33S for proton energies in the 0.20 0.85 MeV range. The energies of eighty-one resonances were measured with an average precision of 0.24 percent. Four new resonances, at 431.0 l.3, 436.9 1.3, 480.1 l.0, and 725.5 1.2 keV, were observed in the 22Ne(p, )23Na reaction, and one new resonance, at 501.4 l.4 keV, was found in the 25Mg(p, )26Al reaction.
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Cited by (16)
Nuclear Data Sheets for A=24
2022, Nuclear Data SheetsEvaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for 24N, 24O, 24F, 24Ne, 24Na, 24Mg, 24Al, and 24Si. This evaluation for A=24 supersedes the earlier one by R. B. Firestone (2007Fi14).
Highlights of this evaluation are the following:
In 24O, the 7.4- and 7.65-MeV groups reported in 1H(24O,p′) (2012Ts03) and 9Be(26F,nX) (2011Ho05), respectively, are considered as separate states in this evaluation, since the former one was observed to decay by only one neutron emission to 23O, while the latter one by two sequential neutrons to 22O. Based on assigned configurations, the 7.4- and 7.6-MeV groups are tentatively assigned negative and positive parities, respectively. Additional study would be useful to determine if these states are same or different.
In 24Na, 2014Fi01 (n,γ) proposed Jπ=(0,1,2)− for 4048.8 keV level based on weaker population from the capture state (Jπ=1+,2+) and mentioned to reexamine the Jπ=0+ assignment, suggested in earlier evaluations (1990En08, 2007Fi02).
This evaluation includes the first observation of E0 transition, strength ρ2(E0)=0.380 70, for the 6432 keV transition from 0+ state at 6432 to 0+ g.s. in 24Mg reported in 2020Do10. Authors proposed the first-excited 0+ state of 24Mg to be superdeformed.
In 24Al, the excited level energies deduced from (3He,t) measurements reported by different research groups vary significantly and it was not clear if some of those levels were same or different. Additional measurements are needed.
Nuclear Structure and Decay Data for A=31 Isobars
2022, Nuclear Data SheetsExperimental nuclear spectroscopic data are evaluated for 11 known nuclides of mass 31 (F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K). Detailed evaluated information is presented for each reaction and decay experiment. Combining all the available data, recommended values are provided for energies, spins and parities, and half-lives of levels, with energies, branching ratios and multipolarities of γ radiations, and characteristics of β and α radiations in radioactive decays. 31P is the most extensively studied one among all nuclides via various reactions and decays, followed by 31S, 31Si, 31Mg and 31Al. Information for excited states in 31Ne, 31Na, 31Cl, 31Ar and 31K are limited; no excited states have yet been identified in 31F, even its ground-state half-life is unknown. Significant new data have become available for the structure of 31S, with its relevance to astrophysical applications. This work supersedes the earlier evaluation of A=31 by 2013Ou01, with literature cutoff date of Feb 15, 2013.
Nuclear Data Sheets for A=23
2021, Nuclear Data SheetsEvaluated spectroscopic data and level schemes from radioactive decay and nuclear reaction studies are presented for 23N, 23O, 23F, 23Ne, 23Na, 23Mg, 23Al, and 23Si. This evaluation for A=23 supersedes the earlier one by R. B. Firestone (2007Fi02).
Highlights of this evaluation are the following:
The recommended absolute γ-ray emission probability (%Pγ) in the 23Ne β-decay was reported with 3.0% systematic uncertainty in 1986BrZQ. In 2007Fi02, the Pγ for the most intense γ ray was recommended with 4% uncertainty. These uncertainties are comparable with the total excited state β feeding uncertainty of 33 l, resulting from 100–67 l (g.s. β feeding) in 23Na (1963Ca06). In this evaluation, notes are added for relative and absolute γ-ray emission probabilities.
From new measurements 2020Kw01 constrain the spin of the 7788 keV level, the dominant resonance state for the 22Na(p,γ)22Mg reaction rate at stellar temperature, in 23Mg to (3/2+,5/2+). Earlier assignment was 7/2+.
The 23Al ε decay scheme appears to be incomplete. Some of the latest reported data on the 23Al ε decay study in the literature need verification.
Nuclear Data Sheets for A = 31
2013, Nuclear Data SheetsNuclear spectroscopic information for the known nuclides of mass 31 (F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar) has been evaluated. A useful source of many of the Adopted Levels for 31P and 31S is presented in Endtʼs evaluations (1998En04,1990En08,1978En02,1973EnVA), however all the adopted properties of levels and gamma rays have been re-evaluated in this work. The data sets for reactions and decays, including all available gamma–ray data, are based mostly on the original literature.
The 31Mg nuclide is a prime candidate for the study of ‘island-of-inversion’ as its ground state and first excited state can only be explained by intruder orbitals in a deformed shell-model approach. 31S is of importance in astrophysics rp-process as a possible ‘bottleneck’ nuclide. There are no data available for excited states in 31F, 31Ne and 31Ar. No gamma transitions are known in 31Cl. For 31Na, only one excited state is known. The radioactive decay characteristics of 31F and 31Ne isotopes have not yet been investigated. The 31S and 31Mg nuclei are currently being pursued intensively by various experimental groups, including recent work by Nuclear Astrophysics group at McMaster, the results of which will soon become available.
Nuclear Data Sheets for A = 34
2012, Nuclear Data SheetsNuclear spectroscopic information for experimentally investigated nuclides of mass 34 (Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca) has been evaluated. The principal sources of the Adopted Levels presented for nuclides close to the stability line are Endtʼs evaluations (1990En08, 1978En02). The data sets for reactions and decays, including all available gamma–ray data, are based mostly on the original literature. There are no data available for the excited states in 34Ne and 34Na. The existence of the 34K and 34Ca nuclides has been searched and reported in a secondary publication but no evidence was found for their detection. Both nuclides are possible candidates for one or two–proton emission. Only upper limits of half–lives have been proposed based on expected cross sections. Decay schemes for the β decays of 34Ne, 34Na, 34Mg, and 34Si are not known. Very little information is available for β–delayed neutron decays of 35Na, 35Mg and 35Si which lead to population of levels in A = 34 nuclides. Neutron–rich nuclides in this mass region are relevant to “island of inversion”.
Nuclear Data Sheets for A = 23
2007, Nuclear Data SheetsThis evaluation of A = 23 has been updated from previous evaluations published in 1998En04, 1990En08, and 1978En02. Coverage includes properties of adopted levels and γ rays, decay-scheme data (energies, intensities and placement of radiations), and cross reference entries. The following tables continue the tradition of showing the systematic relationships between levels in A = 23. These assignments are based on spectroscopic factors and energy differences where .