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AbstractAbstract
[en] 60Fe is of special interest in nuclear astrophysics. Indeed the recent observations of 60Fe characteristic gamma-ray lines by the RHESSI and INTEGRAL spacecrafts allowed to measure the total flux of 60Fe over the Galaxy. Moreover the observation in presolar grains of an excess of the daughter-nuclei of 60Fe, 60Ni, gives constraints on the conditions of formation of the early solar system. However, the cross-sections of some reactions involved in 60Fe nucleosynthesis and included to stellar models are still uncertain. The destruction reaction of 60Fe, 60Fe(n, γ)61Fe, is one of them. The total cross-section can be separate into two contributions: the direct one, involving states below the neutron separation threshold of 61Fe, and the resonant one.We improved 61Fe spectroscopy in order to evaluate the direct capture part of the 60Fe(n, γ)61Fe reaction cross-section. 60Fe(n, γ)61Fe was thus studied via d(60Fe, pγ)61Fe transfer reaction with the CATS/MUST2/EXOGAM setup at LISE-GANIL. DWBA analysis of experimental proton differential cross-sections allowed to extract orbital angular momentum and spectroscopic factors of different populated states identified below the neutron threshold. A comparison of experimental results for 61Fe with experimental results for similar nuclei and with shell-model calculations was also performed. (author)
[fr]
Le 60Fe presente un interet particulier en astrophysique nucleaire. En effet, la recente observation de ses raies gamma caracteristiques par les satellites RHESSI et INTEGRAL permet d'acceder au flux total de 60Fe integre sur toute la Galaxie. De plus, l'observation d'un exces de 60Ni (noyau-fils du 60Fe) dans les grains pre-solaires fournit des contraintes sur les conditions de formation du systeme solaire primitif. Cependant, les sections efficaces de certaines reactions intervenant dans la nucleosynthese du 60Fe et incluses dans les modeles stellaires presentent encore des incertitudes. C'est le cas notamment de la reaction 60Fe(n, γ)61Fe qui est responsable de la destruction du 60Fe. La section efficace totale de cette reaction peut etre divisee en deux parties: la composante directe, impliquant les etats situes sous le seuil de separation neutron du 61Fe, et la composante resonante. Nous avons ameliore les connaissances spectroscopiques du 61Fe afin d'evaluer la contribution de la capture directe au taux de la reaction 60Fe(n, γ)61Fe. Pour cela, nous avons etudie la reaction 60Fe(n, γ)61Fe par la reaction de transfert d(60Fe; pγ)61Fe a l'aide du dispositif experimental CATS/MUST2/EXOGAM sur la ligne LISE au GANIL. L'analyse en DWBA des distributions angulaires experimentales des protons a permis d'extraire les moments angulaires et les facteurs spectroscopiques de differents etats du 61Fe identifies et peuples sous le seuil de separation neutron. Une comparaison des resultats experimentaux obtenus pour le 61Fe avec ceux de noyaux similaires et avec des calculs modele en couches a egalement ete effectueeOriginal Title
Etude de la reaction d'interet astrophysique 60Fe(n; γ)61Fe par reaction de transfert (d,pγ)
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Source
Dec 2011; 177 p; 111 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/INIS/contacts/; Also available from Bibliotheque universitaire de Paris-11, Domaine universitaire Batiment 407, 91405 - Orsay CEDEX (France); These Particules, Noyaux, Cosmos
Record Type
Report
Literature Type
Thesis/Dissertation
Report Number
Country of publication
BETA DECAY RADIOISOTOPES, BETA-MINUS DECAY RADIOISOTOPES, DIRECT REACTIONS, ELECTROMAGNETIC RADIATION, EVEN-EVEN NUCLEI, EVEN-ODD NUCLEI, INTERMEDIATE MASS NUCLEI, IONIZING RADIATIONS, IRON ISOTOPES, ISOTOPES, MATHEMATICAL MODELS, MINUTES LIVING RADIOISOTOPES, NUCLEAR MODELS, NUCLEAR REACTIONS, NUCLEI, PHYSICS, RADIATIONS, RADIOISOTOPES, SYNTHESIS, YEARS LIVING RADIOISOTOPES
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