Resonances in the 15N(α,γ)19F Reaction Between Eα = 1.68 and 2.72 MeV

Rogers, D. W. O.; Beukens, R.P.; Diamond, William

doi:10.1139/p72-322

Cited by 25 publications

(17 citation statements)

References 4 publications

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“…Therefore best value and uncertainty are obtained through a gaussian fit to the histograms, the uncertainty on beam energy determination, that contributes to δE R , is added afterwards. Our determination of E R for the lower energy resonance is significantly different from the literature value of 1323 keV reported in [26], that in turn is based on the data of [28]. It is worth noting that [26] as regards this resonance makes a refer- ence to [29].…”

Section: Experimental Results and Analysiscontrasting

confidence: 99%

Measurement of 1323 and 1487 keV resonances inN15(α,γ)F19with the recoil separator ERNA

et al. 2017

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Background:The origin of fluorine is a widely debated issue. Nevertheless, the 15 N(α, γ) 19 F reaction is a common feature among the various production channels so far proposed. Its reaction rate at relevant temperatures is determined by a number of narrow resonances together with the DC component and the tails of the two broad resonances at E c.m. = 1323 and 1487 keV.Method: Measurement through the direct detection of the 19 F recoil ions with the European Recoil separator for Nuclear Astrophysics (ERNA) were performed. The reaction was initiated by a 15 N beam impinging onto a 4 He windowless gas target. The observed yield of the resonances at E c.m. = 1323 and 1487 keV is used to determine their widths in the α and γ channels. Results:We show that a direct measurement of the cross section of the 15 N(α, γ) 19 F reaction can be successfully obtained with the Recoil Separator ERNA, and the widths Γ γ and Γ α of the two broad resonances have been determined. While a fair agreement is found with earlier determination of the widths of the 1487 keV resonance, a significant difference is found for the 1323 keV resonance Γ α . Conclusions:The revision of the widths of the two more relevant broad resonances in the 15 N(α, γ) 19 F reaction presented in this work is the first step toward a more firm determination of the reaction rate. At present, the residual uncertainty at the temperatures of the 19 F stellar nucleosynthesis is dominated by the uncertainties affecting the Direct Capture component and the 364 keV narrow resonance, both so far investigated only through indirect experiments.

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Section: Experimental Results and Analysiscontrasting

confidence: 99%

Measurement of 1323 and 1487 keV resonances inN15(α,γ)F19with the recoil separator ERNA

et al. 2017

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“…Transitions to lower lying states in 19 F have been reported in Ref. [25]; however, full-energy peaks for these secondary transitions are absent from our singles spectrum while no evidence of the R→ 5938 transition (primary or secondary) exists in the coincidence spectrum. To generate templates for this transition, we assumed an α-particle decay branching ratio of 90% in the simulations.…”

Section: O(pγ) 19 Fsupporting

confidence: 41%

γ-Ray spectroscopy using a binned likelihood approach

Dermigny

Iliadis

Buckner

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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The measurement of a reaction cross section from a pulse height spectrum is a ubiquitous problem in experimental nuclear physics. In γ-ray spectroscopy, this is accomplished frequently by measuring the intensity of full-energy primary transition peaks and correcting the intensities for experimental artifacts, such as detection efficiencies and angular correlations. Implicit in this procedure is the assumption that full-energy peaks do not overlap with any secondary peaks, escape peaks, or environmental backgrounds.However, for complex γ-ray cascades, this is often not the case. Furthermore, this technique is difficult to adapt for coincidence spectroscopy, where intensities depend not only on the detection efficiency, but also the detailed decay scheme. We present a method that incorporates the intensities of the entire spectrum (e.g., primary and secondary transition peaks, escape peaks, Compton continua, etc.) into a statistical model, where the transition intensities and branching ratios can be determined using Bayesian statistical inference.This new method provides an elegant solution to the difficulties associated with analyzing coincidence spectra.

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“…4.38 1972RO33) 1.55 1972RO33) 2.78 1972RO33) 4.38 1971DI18, 1977DI08) 2.78 1971DI18, 1977DI08) 4.00 1971DI18, 1977DI08) 4.55…”

Section: (Aunclassified