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La Cognata M, Pizzone RG, José J, Hernanz M, Cherubini S, Gulino M, Rapisarda GG, Spitaleri C. Application of the THM to the investigation of reactions induced by unstable nuclei: the 18F(p, α) 15O case. EPJ WEB OF CONFERENCES 2019. [DOI: 10.1051/epjconf/201922301030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The Trojan Horse Method is applied to the investigation of the 18F(p,α)15O reaction, by extracting the quasi free contribution to the 2H(18F,α15O)n process. For the first time the method is applied to a reaction of astrophysical importance involving a radioactive nucleus. After investigating the reaction mechanism populating the a + 15O + n exit channel, we could extract the 18F(p,α)15O cross section and calculate the astrophysical factor over the 0 – 1 MeV energy interval. The possibility of exploring the cross section with no need of extrapolation allowed us to to point out the possible occurrence of a 7/2+ state at 126 keV, which would strongly influence the trend of the astrophysical factor at the energies of astrophysical interest. However, the low energy resolution prevents us to draw definite conclusions. Possible astrophysical consequences are also discussed, motivating further work on this reaction.
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Sergi M, Spitaleri C, La Cognata M, Lamia L, Pizzone R, Rapisarda G, Mukhamedzhanov A, Irgaziev B, Tang X, Wischer M, Mrazek J, Kroha V. Resonance Strength Measurement at Astrophysical Energies: The 17O(p, α) 14N Reaction Studied via THM. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201611709016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Scott DA, Caciolli A, Di Leva A, Formicola A, Aliotta M, Anders M, Bemmerer D, Broggini C, Campeggio M, Corvisiero P, Elekes Z, Fülöp Z, Gervino G, Guglielmetti A, Gustavino C, Gyürky G, Imbriani G, Junker M, Laubenstein M, Menegazzo R, Marta M, Napolitani E, Prati P, Rigato V, Roca V, Somorjai E, Salvo C, Straniero O, Strieder F, Szücs T, Terrasi F, Trezzi D. First direct measurement of the 17O(p,γ)18F reaction cross section at Gamow energies for classical novae. PHYSICAL REVIEW LETTERS 2012; 109:202501. [PMID: 23215474 DOI: 10.1103/physrevlett.109.202501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Indexed: 06/01/2023]
Abstract
Classical novae are important contributors to the abundances of key isotopes, such as the radioactive (18)F, whose observation by satellite missions could provide constraints on nucleosynthesis models in novae. The (17)O(p,γ)(18)F reaction plays a critical role in the synthesis of both oxygen and fluorine isotopes, but its reaction rate is not well determined because of the lack of experimental data at energies relevant to novae explosions. In this study, the reaction cross section has been measured directly for the first time in a wide energy range E(c.m.)~/= 200-370 keV appropriate to hydrogen burning in classical novae. In addition, the E(c.m.)=183 keV resonance strength, ωγ=1.67±0.12 μeV, has been measured with the highest precision to date. The uncertainty on the (17)O(p,γ)(18)F reaction rate has been reduced by a factor of 4, thus leading to firmer constraints on accurate models of novae nucleosynthesis.
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Affiliation(s)
- D A Scott
- SUPA, School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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Savin DW, Brickhouse NS, Cowan JJ, Drake RP, Federman SR, Ferland GJ, Frank A, Gudipati MS, Haxton WC, Herbst E, Profumo S, Salama F, Ziurys LM, Zweibel EG. The impact of recent advances in laboratory astrophysics on our understanding of the cosmos. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:036901. [PMID: 22790424 DOI: 10.1088/0034-4885/75/3/036901] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
An emerging theme in modern astrophysics is the connection between astronomical observations and the underlying physical phenomena that drive our cosmos. Both the mechanisms responsible for the observed astrophysical phenomena and the tools used to probe such phenomena-the radiation and particle spectra we observe-have their roots in atomic, molecular, condensed matter, plasma, nuclear and particle physics. Chemistry is implicitly included in both molecular and condensed matter physics. This connection is the theme of the present report, which provides a broad, though non-exhaustive, overview of progress in our understanding of the cosmos resulting from recent theoretical and experimental advances in what is commonly called laboratory astrophysics. This work, carried out by a diverse community of laboratory astrophysicists, is increasingly important as astrophysics transitions into an era of precise measurement and high fidelity modeling.
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Affiliation(s)
- D W Savin
- Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA
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Chafa A, Tatischeff V, Aguer P, Barhoumi S, Coc A, Garrido F, Hernanz M, José J, Kiener J, Lefebvre-Schuhl A, Ouichaoui S, de Séréville N, Thibaud JP. Hydrogen burning of 17O in classical novae. PHYSICAL REVIEW LETTERS 2005; 95:031101. [PMID: 16090732 DOI: 10.1103/physrevlett.95.031101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2005] [Indexed: 05/03/2023]
Abstract
We report on the observation of a previously unknown resonance at E(lab)(R)=194.1+/-0.6 keV in the 17O(p,alpha)14N reaction, with a measured resonance strength omegagamma(palpha)=1.6 +/- 0.2 meV. We studied in the same experiment the 17O(p,gamma)18F reaction by an activation method and the resonance-strength ratio was found to be omegagamma(palpha)/omegagamma(pgamma) = 470 +/- 50. The corresponding excitation energy in the 18F compound nucleus was determined to be 5789.8 +/- 0.3 keV by gamma-ray measurements using the 14N(alpha, gamma)18F reaction. These new resonance properties have important consequences for 17O nucleosynthesis and gamma-ray astronomy of classical novae.
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Affiliation(s)
- A Chafa
- USTHB-Faculté de Physique, BP 32, El-Alia, 16111 Bab Ezzouar, Algiers, Algeria
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Bardayan DW, Batchelder JC, Blackmon JC, Champagne AE, Davinson T, Fitzgerald R, Hix WR, Iliadis C, Kozub RL, Ma Z, Parete-Koon S, Parker PD, Shu N, Smith MS, Woods PJ. Strength of the 18F(p,alpha)15O resonance at Ec.m. = 330 keV. PHYSICAL REVIEW LETTERS 2002; 89:262501. [PMID: 12484811 DOI: 10.1103/physrevlett.89.262501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Indexed: 05/24/2023]
Abstract
Production of the radioisotope 18F in novae is severely constrained by the rate of the 18F(p,alpha)15O reaction. A resonance at E(c.m.)=330 keV may strongly enhance the 18F(p,alpha)15O reaction rate, but its strength has been very uncertain. We have determined the strength of this important resonance by measuring the 18F(p,alpha)15O cross section on and off resonance using a radioactive 18F beam at the ORNL Holifield Radioactive Ion Beam Facility. We find that its resonance strength is 1.48+/-0.46 eV, and that it dominates the 18F(p,alpha)15O reaction rate over a significant range of temperatures characteristic of ONeMg novae.
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Affiliation(s)
- D W Bardayan
- Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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