Recoil separator ERNA: acceptances in angle and energy

Rogalla, Detlef; Schürmann, D.; Strieder, F.; Aliotta, M.; DECESARE, N; Leva, A. Di; Lubritto, Carmine; D’Onofrio, Antonio; Gialanella, L.; Imbriani, G.; Kluge, J.; Ordine, A.; Roca, V.; Röcken, H.; Rolfs, C.; Romano, M.; Schümann, F.; Terrasi, F.; Trautvetter, H. P.

doi:10.1016/j.nima.2003.07.001

Cited by 25 publications

(25 citation statements)

References 12 publications

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“…This condition is actually fulfilled in low-mass AGB stars undergoing thermal pulses, where the 13 C(α, n) 16 O reaction is known to be the main neutron source powering the sprocess nucleosynthesis in their He-rich mantel [8]. The competition with some reactions that destroy 15 N and/or 19 F, such as 15 N(p,α) 12 C, 19 F(n,γ) 20 F, 19 F(p,α) 16 O, and 19 F(α,p) 22 Ne, should also be carefully considered, see e.g. Refs.…”

Section: Introductionmentioning

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: Introductionmentioning

confidence: 99%

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

et al. 2017

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“…for no angular deflection), 100% of ions within ±8% of the energy for which the separator was tuned were transmitted to the end of St. George. A similar technique was employed to determine the energy acceptance of the ERNA recoil separator [14,15]. Transmission through the recoil separator was determined by comparing beam current measurements provided by the Faraday cups at the target location and in the recoil detection plane, where equal currents correspond to 100% transmission.…”

Section: Energy Acceptance Measurement Methodsmentioning

confidence: 99%

Energy acceptance of the St. George recoil separator

Meisel

Moran

Gilardy

et al. 2017

Nuclear Instruments and Methods in Physics Research Section A:

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Radiative alpha-capture, (α, γ), reactions play a critical role in nucleosynthesis and nuclear energy generation in a variety of astrophysical environments. The St. George recoil separator at the University of Notre Dame's Nuclear Science Laboratory was developed to measure (α, γ) reactions in inverse kinematics via recoil detection in order to obtain nuclear reaction cross sections at the low energies of astrophysical interest, while avoiding the γ-background that plagues traditional measurement techniques. Due to the γ ray produced by the nuclear reaction at the target location, recoil nuclei are produced with a variety of energies and angles, all of which must be accepted by St. George in order to accurately determine the reaction cross section. We demonstrate the energy acceptance of the St. George recoil separator using primary beams of helium, hydrogen, neon, and oxygen, spanning the magnetic and electric rigidity phase space populated by recoils of anticipated (α, γ) reaction measurements. We find the performance of St. George meets the design specifications, demonstrating its suitability for (α, γ) reaction measurements of astrophysical interest.

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“…It would be unrealistic to install a detector system right behind the mass slits given the large background expected at that position [4][5][6][7]. The section following the Wien filter, with two 26°dipole magnets, provides an additional momentum separation to improve the background rejection.…”

Section: General Layoutmentioning

confidence: 99%

“…All existing recoil separators [3][4][5][6][7] suffer from so-called leaky beams. These are beam particles that were not rejected at the mass slits because of pathological trajectories.…”

Section: Identification Of Background Trajectoriesmentioning

confidence: 99%

“…Alternatively, the technique of inverse kinematics using heavy ion beams bombarding a helium target allows for the detection of the reaction product in coincidence with the c-ray emission. This method is efficient at reducing the three background contributions but requires a recoil mass separator in order to reject the beam ions that did not interact in the target [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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