Study of fusion hindrance in the system 12C+24Mg
| Autor: | T. Van Patten, D. Brugnara, Tea Mijatović, G. Montagnoli, M. Heine, E. Fioretto, I. Zanon, G. Colucci, L. Corradi, P. Čolović, S. Bottoni, C. L. Jiang, F. Galtarossa, Marco Mazzocco, Suzana Szilner, F. Scarlassara, G. Jaworski, Marco Siciliano, Alberto M. Stefanini, Alain Goasduff |
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| Přispěvatelé: | Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), Istituto Nazionale di Fisica Nucleare (INFN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2020 |
| Předmět: |
Physics
Excitation function History Fusion 010308 nuclear & particles physics Evaporation [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex] Tandem accelerator 01 natural sciences 7. Clean energy nuclear reaction fusion sub-barrier Computer Science Applications Education Nuclear physics Stars Orders of magnitude (time) 13. Climate action 0103 physical sciences [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] 010306 general physics |
| Zdroj: | Journal of Physics: Conference Series 27th International Nuclear Physics Conference (INPC 2019) 27th International Nuclear Physics Conference (INPC 2019), Jul 2019, Glasgow, United Kingdom. pp.012098, ⟨10.1088/1742-6596/1643/1/012098⟩ |
| ISSN: | 1742-6596 1742-6588 |
| Popis: | The phenomenon of fusion hindrance may have important consequences on the nuclear processes occurring in astrophysical scenarios, if it is a general behaviour of heavy-ion fusion at extreme sub-barrier energies, including reactions involving lighter systems, e.g. reactions in the carbon and oxygen burning stages of heavy stars. The hindrance is generally identified by the observation of a maximum of the S-factor vs. energy. Whether there is an S-factor maximum at very low energies for systems with a positive fusion Q-value is an experimentally challenging question. Our aim has been to search evidence for fusion hindrance in 12C + 24Mg which is a medium-light systems with positive Q-value for fusion, besides the heavier cases where hindrance is recognised to be a general phenomenon. The experiment has been performed at the XTU Tandem accelerator of LNL by directly detecting the fusion evaporation residues at very forward angles. The excitation function has been extended down to ≃10μb, i.e. 4 orders of magnitude lower than previous measurements and we observe that the S-factor develops a clear maximum vs. energy. Coupled-Channels calculations using a Woods-Saxon potential give a good account of the data near and above the barrier but over predict the cross sections at very low energies. Therefore the hindrance phenomenon is clearly recognised in 12 C + 24 Mg with an energy threshold that nicely fits the systematics in several medium-light systems. The fusion cross sections at the hindrance threshold show that the highest value (as=1.6mb) is indeed found for this system. It may be possible to extend the measurements further down in energy. |
| Databáze: | OpenAIRE |
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