Evolution of collective and noncollective structures in Xe 123

An experiment involving a heavy-ion-induced fusion-evaporation reaction was carried out where high-spin states of Xe123 were populated in the Se80(Ca48,5n)Xe123 reaction at 207 MeV beam energy. Gamma-ray coincidence events were recorded with the Gammasphere Ge detector array. The previously known level scheme was confirmed and enhanced with the addition of five new band structures and several interband transitions. Cranked Nilsson-Strutinsky (CNS) calculations were performed and compared with the experimental results in order to assign configurations to the bands

Core excitations beyond maximally aligned configurations in 123I

High-spin states in 123I have been populated in the 80Se(48Ca,p4n)123I reaction at 207 MeV and γ-ray coincidence events have been recorded with the Gammasphere spectrometer. The level scheme of 123I has been extended up to spin I=63/2. The nucleus undergoes a shape transition from moderately deformed states with collective rotation at low spins to noncollective oblate configurations at higher spins. Maximally aligned terminating states involving all nine particles outside the 114Sn core and states with one particle antialigned are identified. A large number of weak transitions feed the terminating states. Cranked Nilsson-Strutinsky calculations have been performed to determine possible configurations for the observed energy levels

Highly deformed band structures due to core excitations in Xe 123

High-spin states in Xe123 were populated in the Se80(Ca48, 5n)Xe123 reaction at a beam energy of 207 MeV. γ-ray coincidence events were recorded with the Gammasphere spectrometer. Four new high-spin bands have been discovered in this nucleus. The bands are compared with those calculated within the framework of cranked Nilsson-Strutinsky and cranked Nilsson-Strutinsky-Bogoliubov models. It is concluded that the configurations of the bands involve two-proton excitations across the Z=50 as well as excitation of neutrons across the N=82 shell gaps resulting in a large deformation, 2≈0.30 and γ≈5°C

Collective and noncollective states in 120Te

High-spin states in 120Te were populated in the reaction 80Se(48Ca, α4n)120Te at a beam energy of 207 MeV and γ-ray coincidences were measured using the Gammasphere spectrometer. The previously known level scheme is extended to higher spin and new interband transitions and side-feeding branches are established. Five highly deformed rotational bands, extending up to almost I=50, are observed for the first time. The bands are compared with similar structures found recently in neighboring nuclei. The experimental results are interpreted within the framework of the cranked Nilsson-Strutinsky model. Configuration assignments to several terminating states and to the high-spin bands are discussed

High-spin rotational bands in 123I

High-spin states in 123I were populated in the reaction 80Se(48Ca,p4n)123I at a beam energy of 207 MeV and γ-ray coincidence events were measured using the Gammasphere spectrometer. Three weakly populated, high-spin rotational bands have been discovered with characteristics similar to those of the long collective bands recently observed in other nuclei of this mass region. Configuration assignments are proposed based on calculations within the framework of the cranked Nilsson-Strutinsky approach

Observation of high-spin bands with large moments of inertia in Xe 124

High-spin states in Xe124 have been populated using the Se80(Ca48,4n) reaction at a beam energy of 207 MeV and high-multiplicity, γ-ray coincidence events were measured using the Gammasphere spectrometer. Six high-spin bands with large moments of inertia, similar to those observed in neighboring nuclei, have been observed. The experimental results are compared with calculations within the framework of the cranked Nilsson-Strutinsky model. It is suggested that the configurations of the bands involve excitations of protons across the Z=50 shell gap coupled to neutrons within the N=50-82 shell or excited across the N=82 shell closure

Revised level structure of Te 120

The level scheme of the nucleus Te120, populated in the reaction Se80(Ca48,α4n), was reinvestigated using γ-ray coincidence data measured with the Gammasphere spectrometer. Previously, five high-spin rotational bands were discovered in this nucleus. The present reinvestigation revealed that the decay of band b1 is more complex than suggested in the earlier work and that it cannot be uniquely determined. Furthermore, a number of new transitions are added to the level scheme. The implications for the spin assignments and excitation energies of the five bands and for comparisons with cranked Nilsson-Strutinsky calculations are discussed

M1 and E2 transition rates from core-excited states in semi-magic 94Ru

Lifetimes of high-spin states have been measured in the semi-magic (N= 50) nucleus 94Ru. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru* fusion-evaporation reaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from ?-rays emitted while the residual nuclei were slowing down in a thick 6mg/cm^2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I= (13 - 20) ? have been measured, five of which were determined for the first time. The corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations. © 2018, SIF, Springer-Verlag GmbH Germany, part of Springer Nature.National Brain Research Centre Vetenskapsrådet Göran Gustafssons Stiftelse för Naturvetenskaplig och Medicinsk Forskning Firat University Scientific Research Projects Management Unit Ministerio de Economía y Competitividad Science and Technology Facilities CouncilWe thank the operators of the GANIL cyclotrons for providing the beam, their cooperation and technical support. We would also like to thank the EXOGAM, DIAMANT and Neutron Wall Collaborations. This work was supported by the Swedish Research Council under Grant Nos. 621-2014-5558, 621-2012-3805, and 621-2013-4323 and the Göran Gustafsson foundation, the Scientific Research Projects Coordination Unit of Istanbul University Project No. 47886 and 48101, the UK STFC under grant number ST/L005727/1, the Spanish Ministerio de Economía y Competitividad under grant FPA2014-52823-C2-1-P and the program Severo Ochoa (SEV-2014-0398), the Polish National Research Centre contracts no. 2013/08/M/ST2 /00257 (LEA COPIGAL) and 2016/22/M/ST2/00269, the Scientific and Technological Council of Turkey (Proj. no. 114F473). BMN, IK, ZD and JT acknowledge the financial support of GINOP-2.3.3-15-2016-00034. IK was supported by National Research, Development and Innovation Office NK-FIH, contract number PD 124717. The computations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at PDC, KTH, Stockholm

On the creation of the 17 MeV X boson in the 17.6 MeV M1 transition of 8Be

Electron-positron angular correlations were remeasured for the 17.6 MeV (Jπ = 1+ → 0+) ground state transition in 8Be using an improved setup compared to one we used previously. Significant deviations from the internal pair creation was observed at large angles in the angular correlations, which supports that, in an intermediate step, a neutral isoscalar particle with a mass of 17.0±0.5 (stat)±0.5 (sys) MeV/c2 and Jπ = 1+ was created

Band structures in doubly-odd 100^{100}Rh

High spin states of $^{100}$Rh have been populated using the reaction $^{70}$Zn+$^{36}$S at 130 MeV. $\gamma$-rays were detected with the EUROGAM2 array. The level structure of $^{100}$Rh has been extended up to 14.41 MeV excitation energy. Several band structures are observed. A band based on a I$^{\pi}$=8$^-$ state is developed up to the I$^{\pi}$=24$^-$ level. It is assigned as the $\pi$ $g_{9/2}^{-5}$ $\nu$ $h_{11/2}$ configuration