High resolution investigation of resonances in 19F

Sellin, D.L.; Newson, H.W.; Bilpuch, E.G.

doi:10.1016/0003-4916(69)90138-9

Cited by 22 publications

(61 citation statements)

References 15 publications

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“…Resonance strengths have been measured directly for 19 resonances at energies of E cm r = 89 − 1892 keV by Wiescher et al [252] and Vogelaar et al [248]. At variance with Angulo et al [7], we use published and derived values of partial widths [260,212,154] in order to integrate broad resonance contributions numerically. Additional data were provided by 15 N+α studies and by other experiments [224,192].…”

Section: 24×10 −02mentioning

confidence: 99%

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

et al. 2010

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Numerical values of charged-particle thermonuclear reaction rates for nuclei in the A=14 to 40 region are tabulated. The results are obtained using a method, based on Monte Carlo techniques, that has been described in the preceding paper of this series (Paper I). We present a low rate, median rate and high rate which correspond to the 0.16, 0.50 and 0.84 quantiles, respectively, of the cumulative reaction rate distribution. The meaning of these quantities is in general different from the commonly reported, but statistically meaningless expressions, "lower limit", "nominal value" and "upper limit" of the total reaction rate. In addition, we approximate the Monte Carlo probability density function of the total reaction rate by a lognormal distribution and tabulate the lognormal parameters µ and σ at each temperature. We also provide a quantitative measure (Anderson-Darling test statistic) for the reliability of the lognormal approximation. The user can implement the approximate lognormal reaction rate probability density functions directly in a stellar model code for studies of stellar energy generation and nucleosynthesis. For each reaction, the Monte Carlo reaction rate probability density functions, together with their lognormal approximations, are displayed graphically for selected temperatures in order to provide a visual impression. Our new reaction rates are appropriate for bare nuclei in the laboratory. The nuclear physics input used to derive our reaction rates is presented in the subsequent paper of this series (Paper III). In the fourth paper of this series (Paper IV) we compare our new reaction rates to previous results.

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Section: 24×10 −02mentioning

confidence: 99%

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

et al. 2010

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“…In addition, resonance energies less than 2 MeV were adopted from the 18 O(p, γ ) 19 F reaction input file (see Appendix C.1). Sellin et al (1969), Orihara et al (1973), Almanza et al (1975), and Murillo et al (1979) provided values for the higher resonance energies and partial widths, and Q values and masses are from Wang et al (2012). Our adopted strengths for the 20 and 90 keV resonances agree with La Cognata et al (2010a).…”

Section: C2mentioning

confidence: 99%

“…1. Up to Er=2 MeV, input data are taken from the same source as for the 18O(p,g)19F reaction (see previous table), except for comments below; for higher energies the partial widths are adopted from Sellin et al (1969), Orihara et al (1973), Almanza et al (1975), and Murillo et al (1979). 6.…”

Section: C2mentioning

confidence: 99%

STARLIB: A next-generation reaction-rate library for nuclear astrophysics

Sallaska¹,

Iliadis²,

Chapmagne³

et al. 2013

Proceedings of XII International Symposium on Nuclei in the Cosmos — PoS(NIC XII)

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STARLIB is a next-generation, all-purpose nuclear reaction-rate library. For the first time, this library provides the rate probability density at all temperature grid points for convenient implementation in models of stellar phenomena. The recommended rate and its associated uncertainties are also included. Currently, uncertainties are absent from all other rate libraries, and, although estimates have been attempted in previous evaluations and compilations, these are generally not based on rigorous statistical definitions. A common standard for deriving uncertainties is clearly warranted. STARLIB represents a first step in addressing this deficiency by providing a tabular, up-to-date database that supplies not only the rate and its uncertainty but also its distribution. Because a majority of rates are lognormally distributed, this allows the construction of rate probability densities from the columns of STARLIB. This structure is based on a recently suggested Monte Carlo method to calculate reaction rates, where uncertainties are rigorously defined. In STARLIB, experimental rates are supplemented with: (1) theoretical TALYS rates for reactions for which no experimental input is available, and (2) laboratory and theoretical weak rates. STARLIB includes all types of reactions of astrophysical interest to Z = 83, such as (p, γ ), (p, α), (α, n), and corresponding reverse rates. Strong rates account for thermal target excitations. Here, we summarize our Monte Carlo formalism, introduce the library, compare methods of correcting rates for stellar environments, and discuss how to implement our library in Monte Carlo nucleosynthesis studies. We also present a method for accessing STARLIB on the Internet and outline updated Monte Carlo-based rates.

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“…The prominent structures in the excitation functions up to a proton energy of about 7 MeV were ascribed [2,3] to resonances in the compound nucleus 19F. At lower bombarding energies (Ep less than 3.4 MeV), information about isospin, spin and parity of these resonances was obtained from the measurement of elastic scattering data [4,5], and by the analysis of neutron angular distributions from the 1 s O (p, n) reaction [6]. At proton energies greater than 10 MeV, the (p, n) reaction was interpreted as direct charge-exchange and the neutron angular distributions were used to study the effective residual two-body force in nuclear reactions [7].…”

Section: Introductionmentioning

confidence: 99%

Investigation of two resonances in the18O(p, n)18F reaction

Fritsch¹,

Büchs²,

Finckh³

et al. 1973

Z. Physik

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Excitation functions for the 180(p, n)lSF reaction were measured at bombarding energies Ep=4.6 to 6.6 MeV. In and near two resonances of the yield curves at Ep-----5.622 and 6.061 MeV, angular distributions were measured with neutron timeof-flight techniques. The strong neutron decay to the T= 1 state in 18F and the similarity of the 1SO(p, n) and 180(n, n) yield curves give good evidence that the structures in the 180(p, n) yield curve arise from the formation of T= 3/2 states in 19F. A twolevel-analysis does not give satisfactory fits to the strongly asymmetric angular distributions.

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High resolution investigation of resonances in 19F

Cited by 22 publications

References 15 publications

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

Charged-particle thermonuclear reaction rates: II. Tables and graphs of reaction rates and probability density functions

STARLIB: A next-generation reaction-rate library for nuclear astrophysics

Investigation of two resonances in the18O(p, n)18F reaction

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