Conférences et séminaires » Séminaire présenté par le Dr. Megumi NIIKURA, IPN Orsay

Séminaire présenté par le Dr. Megumi NIIKURA, IPN Orsay

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Lifetime measurement in 72,74Zn by Recoil-distance Doppler-shift method

Par : Dr. Megumi NIIKURA, IPN Orsay, France
Date : mardi 3 avril 2012 à 11h00
Lieu : IPHC, Salle de Réunion 2e étage du Bâtiment 27

Résumé :

There has been a continuous interest in the study of the structure effects of neutron subshell closure at N = 40 close to proton magicity at Z = 28. Recently the doubly-magic character of 68Ni is intensively studied both from the theoretical and experimental points of view. One of the most interesting features is the sudden increase in collectivity in the vicinity of 68Ni by an apparent over occupation of the neutron 1g9/2 orbit. The role of the neutron 1g9/2 orbit in the onset of collectivity has been debated in the past. It turns out that the lowest-lying three Nilsson orbitals originating from the spherical νg9/2 orbit are all strongly down-sloping for both prolate and oblate shapes, which would make deformation energetically favorable in 72-74Zn. Recent shell-model calculations also pointed out the importance of the g9/2 orbit for understanding the evolution of collectivity around 68Ni. In order to investigate how collectivity develops in this region, we performed the lifetime measurement of first 2+ state in 72,74Zn by means of recoil-distance Doppler-shift (RDDS) method. In the seminar I will present the results of our experiment and comparisons recent theoretical calculations. The global property of the collectivities in this region will be also discussed.

Personne à contacter : Radomira LOZEVA