Mesures des vies moyennes des premiers états excités Du Noyau 28Si

Aléonard, M.M.; Castéra, D.; Hubert, Ph.; Leccia, F.; Mennrath, P.; Thibaud, J. P.

doi:10.1016/0375-9474(70)91089-4

Cited by 25 publications

(2 citation statements)

References 24 publications

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“…Hence the lifetime of the 8,945 keV level ranges between 90 and 110 fs, dependent on assumptions about the uncontrolled amount of oxygen in the target. The present measurement leads to a rejection of lifetime values near 60 fs reported in [5,9] and is compatible with values of 105+15, 110+30 and 104_+17 fs, reported in [6,10,11]. In the course of this work we adopt the weighted mean r = 106___ 15 fs of the last three measurements.…”

Section: Angular Distributions Linear Polarizations and Lifetimessupporting

confidence: 87%

Search for missing predicted high-spin states in28Si

Glatz

Lickert

Burkard

et al. 1986

Z. Physik A - Atomic Nuclei

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New shell model calculations have predicted several high-spin (P = 5 + and 6 +) levels in 28Si near 10 MeV excitation energy which are missing from or ambiguous in existing experimental studies. Angular distributions, linear polarizations and Doppler-shifts of ),-rays have been measured for the 7-decay of the Ep = 1,911 and 2,073 KeV resonances of the 27Al(p, 7) reaction in an attempt to discover these missing states or confirm the discrepancies between experiment and theory. The excitation energies and spin-parities of the resonances were determined as 13,424.4 _+ 0.2 keV, P=5 § and 13,582.3_+0.5 keV, P=6 +. States populated in the 7-decay of these resonances were assigned spins and parities as follows: 11,777keV, F=5+; ll,331keV, P=6+; 10,417keV, P=5+; 9,417 keV, P=4 + and 8,945 keV, P=5 +. On the basis of 7-ray transition rates T=I is assigned to the 13,424 keV level and T=0 to the 10,417 and 11,777 keV levels. With the new data excellent agreement is achieved between the experimental spectrum of 28Si and the new shell model predictions. These data provide evidence for a K~=3 + rotational band comprised by the 6, 276, 6,889, 8,945 and 11,331 keV levels. This band emerges also from the shell model wave functions as do the/U=0 + bands based on the ground state and the 6,691 keV state.

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Section: Angular Distributions Linear Polarizations and Lifetimessupporting

confidence: 87%

Search for missing predicted high-spin states in28Si

Glatz

Lickert

Burkard

et al. 1986

Z. Physik A - Atomic Nuclei

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“…La méthode de calcul du facteur F(i), déjà exposée par ailleurs [29], est basée sur le travail de Blaugrund [30]. Les résultats sont présentés dans le tableau III.…”

Section: Rapports D'embranchement Des Niveauxunclassified

Rapports d'embranchement, vies moyennes et mélanges multipolaires dans le noyau 24Mg

et al. 1973

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Les rapports d'embranchement et les vies moyennes des premiers états excités du 24Mg ont été déterminés à l'aide de la réaction 23Na(p, γ) 24Mg dans le domaine d'énergie Ep = 600-1 500 keV. La mesure des vies moyennes par la méthode de l'atténuation de l'effet Doppler conduit aux valeurs : τ = 2 000 ± 450, 40 ± 4, 88 ± 11, 120 ± 16, 83 ± 10, 110 ± 17, 2000 ± 550, 25 ± 5, 35 ± 11, 11 ± 7, 29 ± 7, 20 ± 7 et 25 ± 10 fs, respectivement pour les niveaux Ex = 1,37 ; 4,12 ; 4,24 ; 5,24 ; 6,01 ; 6,43 ; 7,62 ; 7,75 ; 7,81 ; 8,43 ; 8,65 ; 8,86 et 9,52 MeV. Les mesures de distributions angulaires des rayonnements γ nous ont également permis de mesurer les mélanges multipolaires E 2/M 1 des transitions issues des niveaux Ex = 4,24 (2+) ; 5,24 (3 +) et 7,81 MeV (5+). Les valeurs expérimentales des B (E 2) ont été comparées avec les prévisions des modèles collectifs et du modèle en couches

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