Solving nuclear shape conundrum at HIE-ISOLDE

International Workshop on Discovery Physics at the LHC 2012

Orce, J.N.^1

Department of Physics and Astronomy, University of the Western Cape, P/B X17, ZA-7535 Bellville, South Africa^1

关键词: Bombarding energies;    Coulomb excitation;    Diagonal matrix elements;    European institutions;    Precise measurements;    Quadrupole moments;    Radioactive ion beam facility;    Transitional matrix;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/455/1/012041/pdf
DOI  :  10.1088/1742-6596/455/1/012041

来源: IOP

【 摘 要 】

It is the purpose of this paper to illustrate some of the low-energy nuclear physics that we want to pursue at the new HIE-ISOLDE radioactive-ion-beam facility at CERN. The University of the Western Cape leads an experimental proposal and co-authors two Letters of Intent, in collaboration with European institutions, at HIE-ISOLDE. Timely topics such as the «Exploration of K-isomerism using unique high-K isomeric beams-CERN-INTC-I-101» and «Shape changes and proton-neutron pairing around the N = Z line-CERN-INTC-I-102» are addressed in these Letters of Intent. Our experimental proposal aims at performing a multi-step Coulomb-excitation of radioactive70Se ion beams using the208Pb(70Se,70Se*)208Pb* reaction at a bombarding energy of 5.5 MeV/u. The physics goal is a precise measurement of the (2+1Eˆ2 2+1) diagonal matrix element, related to the spectroscopic quadrupole moment, in70Se. Full simulations presented in this work show distinct angular distributions for plausible values of the spectroscopic quadrupole moment; with a predicted uncertainty of approximately ±0.1 eb. Additional diagonal and transitional matrix elements will also be obtained. These results will shed light onto the origin of rarely-found oblate shapes and shape coexistence in this region of rapidly-changing shell structure.