Seven-quasiparticle bands in Ce-139

• The high spin states in the Ce-139 nucleus have been studied by in-beam gamma-spectroscopic techniques using the reaction Te-130(C-12,3n)Ce-139 at E-beam=65 MeV. A gamma detector array, consisting of five Compton-suppressed Clover detectors was used for coincidence measurements. 15 new levels have been proposed and 28 new gamma transitions have been assigned to Ce-139 on the basis of gamma gamma coincidence data. The level scheme of Ce-139 has been extended above the known 70 ns 19/2 isomer up to similar to 6.1 MeV in excitation energy and 35/2h in spin. The spin-parity assignments for most of the newly proposed levels have been made using the deduced Directional Correlation from Oriented states of nuclei (DCO ratio) and the Polarization Directional Correlation from Oriented states (PDCO ratio) for the de-exciting transitions. The observed level structure has been compared with a large basis shell model calculation and also with the predictions from cranked Nilsson-Strutinsky (CNS) calculations. A general consistency has been observed between these two different theoretical approaches.

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NATURVETENSKAP  -- Fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences (hsv//eng)

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