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Analysis of high statistics triple coincidence fission γ data from 252Cf at Gammasphere including angular correlations yielded well-expanded high-spin level schemes with more complete and reliable spin/parity assignments for 82Ge, 118,120,122Cd and 114,115Rh. Both the quasi-particle/hole couplings and quasi-rotational degrees of freedom are implied to play roles in these Cd isotopes. Evidence for triaxial shapes and octupole components in the Cd isotopes is presented. These Cd isotopes may have triaxial deformations. High-spin level schemes of 114,115Rh have been established for the first time. The existence of a relatively large signature splitting and an yrare band shows typical features of a triaxially deformed nucleus. Possible excited deformed rotational bands are observed, for the first time, in 82Ge. From the multipole mixing ratio measurement, the ground state configurations of 109,111Ru, as well as excited states in 103,107Mo and 111Ru were determined.

With a very high statistics data set with 5.7×1011 triple and higher fold γ coincidences from the spontaneous fission of 252Cf, a wealth of fascinating new collective motions in nuclei with A = 100–112 have been observed. Nothing was known previously about one‐ and two‐phonon γ‐bands in odd‐A nuclei. We discovered the first one‐and two‐ phonon γ vibrational bands in an odd N‐even Z nucleus, 105Mo. The energies of the one‐ and two‐ phonon bands in 104Mo, 105Mo, 106Mo and 108Mo were recently studied and are remarkably similar in energies. The first chiral doublet bands in e‐e nuclei were observed in triaxial 106,108Mo and 110,112Ru while such chiral band in 108Ru are perturbed by its γ‐soft shape. The experimental evidences, including our recent angular correlation studies are presented along with what these new bands are telling us about the evolving collective structures and deformation in this region.

The high spin states of neutron‐rich nuclei in A∼110 region have been carefully investigated by measuring prompt γ‐γ‐γ coincident measurements populated in the spontaneous fission of 252Cf with the Gammasphere detector array. Many new collective bands have been discovered. In this proceeding paper, we introduce some interesting new band structures recently observed by our cooperative groups, that is, the one‐phonon‐ and two‐phonon γ‐vibrational bands in odd‐A 103Nb, 105Mo and 107Tc, the chiral doublet bands in even‐even 106Mo, 110Ru and 112Ru, and the pseudospin partner bands with in 108Tc. The characteristics of these band structures have been discussed.The high spin states of neutron‐rich nuclei in A∼110 region have been carefully investigated by measuring prompt γ‐γ‐γ coincident measurements populated in the spontaneous fission of 252Cf with the Gammasphere detector array. Many new collective bands have been discovered. In this proceeding paper, we introduce some interesting new band structures recently observed by our cooperative groups, that is, the one‐phonon‐ and two‐phonon γ‐vibrational bands in odd‐A 103Nb, 105Mo and 107Tc, the chiral doublet bands in even‐even 106Mo, 110Ru and 112Ru, and the pseudospin partner bands with in 108Tc. The characteristics of these band structures have been discussed.

In an experiment carried out at the 4π Ge detector facility Gammasphere the yields of ternary fission events of 252Cf accompanied by the emission of He, Be and C LCPs were measured. For the first time independent yields were measured for 59 pairs of secondary fragments of the He ternary fission and for many fission fragments detected together with the He, Be and C LCPs. With a reasonable assumption that the detected LCPs predominantly are 4He, 10Be and 14C their yields and the charge distributions of fission fragments were conjointly analyzed in terms of the “energy cost” concept first suggested by Halpern.

New analyses of spontaneous-fission gamma data from our 252Cf Gammasphere runs of 1995 and 2000 have identified new transitions and given improved transition energy and intensity values for known transitions in even-odd fission-product nuclei just beyond the 82-neutron closed shell. New level schemes of N=83 isotones 139Ba83 and 135Te83 and of N=85 isotones 141Ba85, and 139Xe85 are established. Single-particle (hole) excitations and couplings, core excitations, and octupole excitations are assigned to these isotones. A regular sequence found in 135Te is interpreted as a shears band within the tilted-axis cranking model of Frauendorf. The level systematics of N=85 isotones indicate that the octupole excitation moves to higher excitation energy as the Z=50 shell is approached.

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.