Excited states in129I

Abstract

Excited states in 129 I were populated with the 124 Sn( 7 Li,2n) reaction at 23 MeV. In-beam measurements of gamma-ray coincidences were performed with an array of eight HPGe detectors and five LaBr 3 (Ce) scintillation detectors. Based on the γγ coincidence data, a positive parity band structure built on the 7/2 + ground state was established and the πg 7/2 configuration at oblate deformation was assigned to it. The results are compared to Interacting Boson-Fermion model (IBFM) and Total Routhian Surface (TRS) calculations.

High-spin states above the isomers in neutron-rich iodine nuclei near N=82

“…Due to the use of logic delays in the trigger the time (t Decay ) has 800 ns offset, thus the true reaction time corresponds to a t Decay = 800 ns. The shortest lifetimes measured in the focal plane using the present experimental setup is T 1/2 = 60(20) ns and 90 (16) ns in 126 Sb [31]. Further details of the experimental setup consisting VAMOS++, AGATA and EXOGAM can be found in Ref.…”

“…In odd-A Iodine isotopes 127,129 I, collective bands based on πg 7/2 , πd 5/2 and πh 11/2 configurations have been reported. At higher spins, the states associated with a neutron pair breaking, involving orbitals πg 7/2 and νh 11/2 , have also been observed [15,16]. Towards the N = 82, isomeric states (19/2 − and 23/2 + ) dominated by two neutron-hole configurations coupled to the odd number of protons have been identified in 131,133 I (N = 78, 80) [17].…”

Nuclear Physics Opportunities at European Small-Scale Facilities

“…Concerning neutron-rich rare-earth isotopes, fourteen isotopes have been measured for the first time. These include the first measurements of 158 Nd, 160,161 Pm, 162,163 Sm, 164,165 Eu, 164−167 Gd, and 165,167,168 Tb [87,88]. The rare-earth masses are important for understanding the formation of the rare-earth abundance peak at A = 165 in the r-process.…”

“…For cases requiring a high-resolution and high-efficiency detection system, ROSPHERE can alternatively be used as a full HPGe array. A variety of subjects have been addressed in the physics cases, including the role of the negative-parity neutron intruder orbitals in the structure of low-spin states configurations for nuclei near the "island of inversion" [157,158], the study of the nuclear structure near shell and/or subshell closures (see, for example, [159][160][161]), the study of neutron-rich nuclei using low energy transfer/incomplete fusion reactions induced by 7 Li beams ( [162,163]), as well as the interplay between collective and singleparticle degrees of freedom (see Refs. [159][160][161][162][163]).…”

“…A broad range of experimental techniques to cover the relevant interval for lifetimes of excited states in nuclear systems was employed: the fast-timing technique, the RDDS method, and the DSAM method (see Refs. [157][158][159][160][161][162][163] and references therein). Far from the valley of stability, deviations are observed from the conventional single-particle shell structure.…”