New binary and ternary spontaneous modes for [sup 252]Cf and new band structures with gammasphere

J H Hamilton,R W Lougheed,B R S Babu,J Kormicki,K Butler-Moore,R Aryaeinejad,I Y Lee,A Florescu,A V Daniel,G M Ter-Akopian,M F Mohar,J K Hwang,A V Ramayya,M W Drigert,A O Macchiavelli,J F Wild,G S Popeko,Y X Dardenne,Yu Ts Oganessian,M A Stoyer,A Săndulescu ,Qi Lu ,K J Moody ,J.o Rasmussen ,S.g Prussin ,R S Dodder ,S J Zhu ,W Greiner ,M G Wang ,W C ,J D Cole ,T N Ginter ,S J Asztalos ,J K Deng ,Steven Chu ,P M Gore ,E F Jones ,Κ E Gregorich

doi:10.1063/1.52597

Abstract

Prompt γ-γ-γ coincidence studies following spontaneous fission of 252Cf were carried out at Gammasphere first with 36 and later with 72 Ge detectors. Yields and neutron multiplicities were measured directly for Sr-Nd, Zr-Ce Mo-Ba, Ru-Xe, and Pd-Te correlated pairs. A new hot fission mode was discovered going via only 108Mo-144Ba, 107Mo-145Ba, and/or 106Mo-146Ba pairs where one or more of 144,145,146Ba are hyperdeformed at scission with 3:1 axis ratio. For the first time correlated pairs involved in cold ternary fission were observed with the third particle 4He, possibly 6He, and 10Be. The 142-146Ba data provide evidence for the predicted disappearance of stable octupole deformation at high spins. New level structures and isotopes include new octupole deformations, identical bands and other structures.

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