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Biswas, S. et al, & Perez-Vidal, R. M. (2020). Prompt-delayed gamma-ray spectroscopy of neutron-rich In-119, In-121 isotopes. Phys. Rev. C, 102(1), 014326–10pp.
Abstract: Background: The Z = 50 shell closure, near N = 82, is unique in the sense that it is the only shell closure with the spin-orbit partner orbitals, pi g(9/2) and pi g(7/2), enclosing the magic gap. The interaction of the proton hole/particle in the above-mentioned orbitals with neutrons in the nu h(11)(/2) orbital is an important prerequisite to the understanding of the nuclear structure near N = 82 and the nu pi interaction. Purpose: To explore the structural similarity between the high-spin isomeric states in In (Z = 49), Sn (Z = 50), and Sb (Z = 51) isotopes from a microscopic point of view. In addition, to understand the role of a proton hole or particle in the spin-orbit partner orbitals, pi g(9/2) and pi g(7/2), respectively, with neutron holes in the nu h(11)(/2) orbital on these aforementioned isomers. Methods: The fusion and transfer induced fission reaction Be-9(U-238, f) with 6.2 MeV/u beam energy, using a unique setup consisting of AGATA, VAMOS ++, and EXOGAM detectors, was used to populate through the fission process and study the neutron-rich In-119,In-121 isotopes. This setup enabled the prompt-delayed gamma-ray spectroscopy of isotopes in the time range of 100 ns-200 μs. Results: In the odd-A In-119,In-121 isotopes, indications of a short half-life 19/2(-) isomeric state, in addition to the previously known 25/2(+) isomeric state, were observed from the present data. Further, new prompt transitions above the 25/2(+) isomer in In-121 were identified along with reevaluation of its half-life. Conclusions: The experimental data were compared with the theoretical results obtained in the framework of large-scale shell-model calculations in a restricted model space. The <pi g(9/2)nu h(11/2); I vertical bar H vertical bar pi g(9/2) nu h(11/2);I > two-body matrix elements of residual interaction were modified to explain the excitation energies and the B(E2) transition probabilities in the neutron-rich In isotopes. The (i) decreasing trend of E(29/2(+))-E(25/2(+)) in odd-In (with dominant configuration pi g(9/)(2)(-1) nu h(11/2)(-2) and maximum aligned spin of 29/2+) and (ii) increasing trend of E(27/2(+)) – E(23/2(+)) in odd-Sb (with dominant configuration pi g(7/)(2)(+1) nu h(11/2)(-2) and maximum aligned spin of 27/2(+)) with increasing neutron number could be understood as a consequence of hole-hole and particle-hole interactions, respectively.
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Bizzeti, P. G. et al, & Gadea, A. (2010). Transition probabilities in the X(5) candidate Ba-122. Phys. Rev. C, 82(5), 054311–10pp.
Abstract: To investigate the possible X(5) character of Ba-122, suggested by the ground-state band energy pattern, the lifetimes of the lowest yrast states of Ba-122 have been measured, via the recoil distance Doppler-shift method. The relevant levels have been populated by using the Cd-108(O-16,2n)Ba-122 and the Sn-112(C-13, 3n)Ba-122 reactions. The B(E2) values deduced in the present work are compared to the predictions of the X(5) model and to calculations performed in the framework of the IBA-1 and IBA-2 models.
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Blank, B. et al, Agramunt, J., Algora, A., Guadilla, V., Montaner-Piza, A., Morales, A. I., et al. (2016). New neutron-deficient isotopes from Kr-78 fragmentation. Phys. Rev. C, 93(6), 061301–5pp.
Abstract: In an experiment with the RIKEN projectile fragment separator called BigRIPS at the RIKEN Nishina Center, the fragmentation of a Kr-78 beam allowed the observation of new neutron-deficient isotopes at the proton drip line. Clean identification spectra could be produced and Se-63, Kr-67, and Kr-68 were identified for the first time. In addition, Ge-59 was also observed. Three of these isotopes, Ge-59, Se-63, and Kr-67, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes Ge-58, Se-62, and Kr-66 were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic isotopes. These measurements confirm the trend already observed that the empirical parametrization of fragmentation cross sections, EPAX, significantly overestimates experimental cross sections in this mass region.
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R3B Collaboration(Boillos, J. M. et al), & Nacher, E. (2022). Isotopic cross sections of fragmentation residues produced by light projectiles on carbon near 400A MeV. Phys. Rev. C, 105(1), 014611–13pp.
Abstract: We measured 135 cross sections of residual nuclei produced in fragmentation reactions of C-12, N-14, and O-13-16,O-20,O-22 projectiles impinging on a carbon target at kinetic energies of near 400A MeV, most of them for the first time, with the R B-3/LAND setup at the GSI facility in Darmstadt (Germany). The use of this state-of-the-art experimental setup in combination with the inverse kinematics technique gave the full identification in atomic and mass numbers of fragmentation residues with a high precision. The cross sections of these residues were determined with uncertainties below 20% for most of the cases. These data are compared to other previous measurements with stable isotopes and are also used to benchmark different model calculations.
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HARP Collaboration(Apollonio, M. et al), Burguet-Castell, J., Cervera-Villanueva, A., Gomez-Cadenas, J. J., Martin-Albo, J., Novella, P., et al. (2010). Measurements of forward proton production with incident protons and charged pions on nuclear targets at the CERN Proton Synchroton. Phys. Rev. C, 82(4), 045208–33pp.
Abstract: Measurements of the double-differential proton production cross-section d(2 sigma)/dpd Omega in the range of momentum 0.5 GeV/c <= p < 8.0 GeV/c and angle 0.05 rad <= theta < 0.25 rad in collisions of charged pions and protons on beryllium, carbon, aluminium, copper, tin, tantalum, and lead are presented. The data were taken with the large acceptance HARP detector in the T9 beam line of the CERN Proton Synchrotron. Incident particles were identified by an elaborate system of beam detectors and impinged on a target of 5% of a nuclear interaction length. The tracking and identification of the produced particles was performed using the forward spectrometer of the HARP experiment. Results are obtained for the double-differential cross-sections mainly at four incident beam momenta (3, 5, 8, and 12 GeV/c). Measurements are compared with predictions of the GEANT4 and MARS Monte Carlo generators.
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