Revision of the decay data of166?170Re, including new isomers167m,169mRe

Abstract

The neutron-deficient rhenium isotopes 166-17~ were investigated using reactions of 32S with monoisotopic 141pr targets. Gamma-rays following the fl-decays of 166-169Rewere measured for the first time. Four new e-rays with energies of 4.70, 4.83, 4.87, and 5.02 MeV were detected in addition to the known 5.50, 5.26, and 5.06 MeV e-rays. Alpha-decaying isomer pairs were discovered in 167Re and 169Re. The measured half-lives are 2.3(2)s for 166Re, 3.4(4)s and 6.2(5)s for 167Re, 4.4(1)s for 168Re, 8.1(5)s and 16.3(8)s for 169Re, and 9.2(2)s for iV~ The nuclear structure is discussed in terms of single-particle states.

First observation of rotational structures in Re168

“…Meissner et al [6] performed an ec/β + decay experiment to measure the halflife of the ground state, t 1/2 = 4.4(1) s, and estimated its spin/parity to be I π = (5 + , 6 + ) based on the feeding pattern toward the 168 W daughter nucleus. An investigation of the α decay of 172 Ir [7] observed γ-ray transitions in coincidence with the α activity.…”

Excited states in neutron-deficient iridium nuclei populated in radioactive decays ofPt177–181

“…One feature of this h9~2, K = 1/2 band is a large decoupling parameter. As a consequence, the level order is disturbed and its member becomes the ground state of several isotopes of tantalum, rhenium, and iridium [9,12,14,15]. Further, the low-lying band structures accessible by in-beam reactions are limited to the (+ 2) signature rotational states starting with the 2, 2, and 2 members.…”

“…It has been well established in neutron-deficient lutetium (Z =71) to gold (Z =79) nuclei [7 -10] and plays an important role in the rhenium (Z =75) and iridium (Z =77) isotopes [ll -13], where the actual knowledge on level structure is very scarce. Second, the vicinity of deformed states originating from the major d3y2 and hzig2 shells and the hgy2[541] orbital gives rise to a new island of long-lived isomers which has recently been discovered in decay studies of rhenium and iridium nuclei [12, 13].The earlier identification of these isotopes in the very neutron-deficient region was favored due to the strong o.-decay branches and the appealing features of o. spectroscopy such as low background, high detection eKciency, and good energy resolution. Today, using highly efficient detection and coincidence techniques, the Pdecay branches are also experimentally accessible.…”

“…[541] orbital gives rise to a new island of long-lived isomers which has recently been discovered in decay studies of rhenium and iridium nuclei [12, 13].…”

Multiple band structures in169,170Re: Search for the wobbling mode in169Re, and residual-interaction analysis of structures inHartley1, Janssens2, Riedinger3 et al. 2013Phys. Rev. C12050View full textAdd to dashboardCite

“…Information on the observed states and γ rays have been tabulated in Table I. Two decay studies [15,16] of 169 Re were published in 1992 and reported two states that β + decay in addition to weak α branches. An evaluation of the 169 Re data [17] suggested that the I π = (9/2 − ) (t 1/2 = 8.1 s) level is the ground state, while systematics suggest that the (5/2 + ,3/2 + ) (t 1/2 = 15.1 s) state is an isomer.…”