6533b82bfe1ef96bd128e16f

RESEARCH PRODUCT

Decay properties of very-high-spin states in transitional Er nuclei aroundA=154

subject

description

Theγ ray continuum structures of the transitional Er isotopes withA∼154 are studied using the reaction74Ge(84Kr,xn)158−xEr atElab=340 MeV. The measurements include energy spectra, total energies, multiplicities, angular distributions and lifetimes using the DSAM method. The analysis of data confirms the previously observed two-bump structure of the continuum radiation. A meticulous subtraction of discrete contributions proves the persistence of the low-energy bump even at high spins, i.e.I>40ħ. The angular-distribution measurements assign predominant dipole structure to the bump atEγ=0.65 MeV, whereas the bump atEγ=1.3 MeV is of almost pure quadrupole character at high spins. The lifetime measurements give evidence for a strong enhancement of theB(E2) values of the upper bump,B(E2)/Bsp>130. Spin-selection studies reveal, in the spin rangeI=30−50ħ an almost constant energy for the 1.3 MeV bump,ΔE<60 keV.