New exotic neutron-deficient nuclei nearN=82

Abstract

Residual activities produced via 35C1 or 32S beams in thin t12Sn and t~ targets have been studied by y-ray and X-ray spectroscopy techniques behind a He-jet system. Mass identification of the products has been performed by coupling the He-jet to the medium current ion source of an isotope separator. Neutron-deficient nuclei with 137<A<144 have been identified. Decay schemes of several new isotopes as 138Eu (12s), 14~Gd (22s), 143Tb (12s and <17s), 144Dy (9s) and possibly 14~ (11s) have been derived. New informations have also been provided for 137Sm (45s), 139Eu (24s) ,and 144Tb (5s). Data have been presented through systematics. The shapes of these nuclei and their trends versus N and Z have been analysed.

In-beam study of the doubly-odd nucleus 61 140 Pm79 above the 8− β +-decaying isomer

“…In the N=79 odd-odd nuclei from 13~ to 144Tb such isomers are experimentally known [5][6][7] and their spins vary from 6-to 8-depending on which member of the rcsl/2@v 1 h~-l} 2 or rc2ds/2@v 1 h~-l~ 2 multiplets is lowest in energy. Information on states of higher spin above the isomers is very scarce at N = 79 and expecially *Permanent address: Department of Physics, University of Jyv/iskyl/i, Jyvfiskyl~i, Finland ** Permanent address: The Svedberg Laboratory, University of Uppsala, Uppsala, Sweden in the vicinity of the proton number Z = 64, where the proton-neutron residual interaction in the h11/2 orbital can be studied.…”

Prompt and delayed spectroscopy ofTb142using recoil-isomer tagging

“…The neutron-deficient mass 130-140 region of the nuclear chart is known to exhibit nuclear shapes that are triaxial or γ soft, a phenomenon that has been attributed to the shape driving effects of the competing πh 11/2 and νh 11/2 intruder orbitals [20,21]. The 142m2 Tb isomeric state is expected to have a configuration based on a πh 11/2 ⊗ νh 11/2 configuration, as the neighboring odd-proton nuclei ( 141,143 Tb) and odd-neutron nuclei ( 141 Gd, 143 Dy) have yrast bands built on πh 11/2 and νh 11/2 configurations, respectively [22][23][24][25].…”

Discovery of samarium, europium, gadolinium, and terbium isotopes

“…Redon et al described the first observation of 137 Sm in the 1986 paper "Exotic neutron-deficient nuclei near N=82" [25]. Enriched 106 Cd targets were bombarded with a 191 MeV 35 Cl beam from the Grenoble SARA accelerator and 137 Sm was formed in the fusion evaporation residue reaction 106 Cd( 35 Cl,3p1n).…”