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

Abstract

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.

Sub-threshold states in $^{19}$Ne relevant to $^{18}$F(p,$α$)$^{15}$O

“…First, the α-particle width for the 5.34 MeV state has been determined experimentally (Γ α = 1.3 (5) keV) and compared to single-particle width calculated with a potential model, leading to θ 2 α ≈ 0.4 [37], in agreement with theoretical predictions [36]. Other experimental work finds Γ α = 2.51 (10) keV [38] also supporting a strong αcluster contribution for the 5.34 MeV state. Second, the 15 N( 7 Li,t) 19 F reaction was studied at bombarding energies of 15 MeV and 20 MeV [39].…”

Sub-threshold states in Ne19 relevant to F18(p,α)Riley1, Laird2, Séréville3 et al. 2021Phys. Rev. C6060View full textAdd to dashboardCite

“…First, the α-particle width for the 5.34 MeV state has been determined experimentally (Γ α = 1.3 (5) keV) and compared to single-particle width calculated with a potential model, leading to θ 2 α ≈ 0.4 [37], in agreement with theoretical predictions [36]. Other experimental work finds Γ α = 2.51 (10) keV [38] also supporting a strong αcluster contribution for the 5.34 MeV state. Second, the 15 N( 7 Li,t) 19 F reaction was studied at bombarding energies of 15 MeV and 20 MeV [39].…”

Advances in Material Wide Range Temperature Determination by Dual-Color Emissivity Free Methodology in Long-Mid-near Infrared Ranges at Non-stationary Conditions

“…Furthermore, the DC technique has to be used in applications where the emissivity of the materials is not well known, such as in the case of the test performed in the PWT facilities to verify the TPS withstanding the hypersonic plasma interactions [12][13][14][15]. Before testing the methodology in the PWT aerospace field, the Center for Isotopic Research on the Cultural and Environmental heritage (CIRCE) accelerator [16][17][18][19], upgraded both to perform accelerator mass spectrometry (AMS) up to actinides [20][21][22][23][24] and for experimental nuclear astrophysics [25][26][27][28][29][30][31][32] as other AMS systems [33], can be used for the preliminary test at temperature values reaching 1500 • C, with materials that, at the beginning of the process, are characterized by a low emissivity, and increase their emissivity value with a carbon ions implantation.…”