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Cho, Y. et al, & Perez-Vidal, R. M. (2026). Regularity of core coupled high-spin structure in neutron-rich 196-202Au isotopes approaching N=126. Phys. Lett. B, 878, 140558–7pp.
Abstract: Excited states built upon long-lived high-spin isomers in hard-to-reach neutron-rich Au (Z = 79) isotopes were populated using multi-nucleon transfer reactions between 136Xe and 198Pt at 7 MeV/u. These states in 196,198-202Au were identified for the first time using the powerful combination of the VAMOS++ spectrometer, the CATLIFE detection system, and the AGATA 1-ray tracking array. Their measured energies exhibit remarkable regularity as a function of neutron number and are seen to be inherited from the energies of yrast-band members in the corresponding Hg (Z = 80) isotope. Large-scale shell-model calculations reproduce the observed regularity and show that these states arise from the unique-parity orbitals 20h11/2 and v0i13/2 coupled to the Hg core. This regularity is due to the dominant proton configurations of the Hg and Au isotopes, where the level energies are almost independent of different neutron-orbital occupancies. The calculated Au wave functions show significant higher-spin components of the corresponding Hg core, unlike what is expected in the conventional interpretation in terms of the weak-coupling/decoupling limits of the particle-core coupling model.
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Moon, B. et al, & Morales, A. I. (2026). Commissioning and performance of IDATEN: A large fast-timing γ-ray detector array at the RIBF. Nucl. Instrum. Methods Phys. Res. A, 1084, 171239–7pp.
Abstract: A large fast-timing 1-ray detector array has been newly developed under the International Detector Assembly for fast-Timing measurements of Exotic Nuclei (IDATEN) project. The full IDATEN array comprises 82 LaBr3(Ce) 1-ray detectors, of which 46 and 36 are provided by the KHALA and FATIMA collaborations, respectively. To assess the fast-timing performance of this large-scale system with stopped rare-isotope beams, a commissioning experiment was recently carried out at the Radioactive Isotope Beam Factory (RIBF) at RIKEN. Neutron-deficient rare isotopes near 100Sn were produced via in-flight fragmentation of a 124Xe primary beam. The fast-timing capability was evaluated using 96Pd as the reference nucleus by measuring the half-lives of the 2+1 , 4+1 and 6+1 levels, which were populated through the decay of the long-lived 8+1 isomeric state. These results demonstrate the reliability of our experimental setup, including the readout electronics and data acquisition system, thereby validating its readiness for forthcoming physics experiments at the RIBF. Moreover, the measured half-life values are in agreement with previously reported literature values, with some determinations achieving improved precision.
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