Search for High-Spin Isomer in $^{142}$Pr by RI Beam Induced Fusion Reaction at RCNP
ORAL
Abstract
Systematic studies of high-spin shape isomers in $N$=83 isotones provided interesting information on the properties of pairing interactions. The high-spin isomer in $^{142}$Pr, which is not effectively populated by any combinations of stable beams and targets, was searched for in the fusion reaction induced by RI beam, $^{130}$Te($^{17}$N, 5n)$^{142}$Pr, at RCNP, Osaka Univ. The $^{17}$N beam was produced in the $^{9}$Be ($^{18}$O, $^{17}$N) $^{10}$B reaction at 9.1 MeV/u. Gamma-rays at the secondary target were detected by a RCNP Ge array consisting of 14 HPGe detectors. Contaminant $\gamma$-rays due to $\beta$-decay of $^{17}$N and the natural activities could be eliminated with the coincidence requirement that the $^{17}$N particles were detected in the PPAC. The $^{17}$N beam of $\sim$10$^{5}$ pps has been obtained with energy of $\sim$4.2 MeV/u. In the preliminary analyses, clearly seen were the $\gamma$-rays deexciting the states with spins up to 21/2 in $^{141}$Pr and the reported $\gamma$-rays after the decay of (9+) isomer with $T_{1/2}$=61 ns in $^{142}$Pr. The results of $\gamma\gamma$ coincidence analyses searching for the isomers will be presented.
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