[en] A two-step fragmentation experiment has been performed at GSI with the RISING setup. It combines the fragment separator FRS, which allows for the production of radioactive heavy ions at relativistic energies, with a high resolution γ-spectrometer. This combination offers unique possibilities for nuclear structure investigations like the test of shell model predictions far from stability. Within the present work the question if the N=14(16) shell stabilisation in Z=8 oxygen isotopes and the N=20 shell quenching in ³²Mg are symmetric with respect to the isospin projection quantum number Tz has been addressed. New γ-ray decays were found in the neutron deficient ³⁶Ca and ³⁶K by impinging a radioactive ion beam of ³⁷Ca on a secondary ⁹Be target. The fragmentation products were selected with the calorimeter telescope CATE and the emitted γ-rays were measured with Ge Cluster, MINIBALL, and BaF₂ HECTOR detectors. For ³⁶Ca the 2₁⁺→0_g.s.⁺ transition energy was determined to be 3015(16) keV, which is the heaviest T=2 nucleus from which γ-spectroscopic information has been obtained so far. A comparison between the experimental 2₁⁺ energies of ³⁶Ca and its mirror nucleus ³⁶S yielded a mirror energy difference of ΔE_M=-276(16) keV. In order to understand the large ΔE_M value, the experimental single-particle energies from the A=17, T=1/2 mirror nuclei were taken and applied onto modified isospin symmetric USD interactions in shell model calculations. These calculations were in agreement with the experimental result and showed that the experimental single-particle energies may account empirically for the one body part of Thomas-Ehrman and/or Coulomb effects. A method to extract the lifetime of excited states in fragmentation reactions was investigated. Therefore, the dependence between the lifetime of an excited state and the average de-excitation velocity and trajectory of the nuclei in relativistic fragmentation experiments has been studied. Known lifetime values in ³⁴Cl could be confirmed and new values were found for ³⁶K. (orig.)

No abstract available

[en] The presentation will address nuclear structure and shell evolution at extreme isospin values, studied via in-beam gamma-ray spectroscopy at intermediate energies. Besides an introduction of the setup, recent results will be presented. These include shape transitions and deformation at the N=60 island of deformation around ⁹⁶Kr, shell effects for N=70 isotones down to ¹¹⁰Zr, and other topics. This document is composed of an abstract and the slides of the presentation. (authors)

[en] When moving from the valley of stability of stable nuclei to regions of extreme proton to neutron ratios, the standard ordering of nuclear shells may be abandoned in favor of other configurations. The most famous example is the so-called 'Island of Inversion', where ν(f_7/2) states intrude into the sd-shell. Despite the 'Island of Inversion' being already discovered in 1975 [1], not until 20 years later and with the aid of the then new experimental technique of intermediate Coulomb excitation of radioactive beams following projectile fragmentation the large collectivity of 3^2Mg due to intruder states could be established [2]. However, spectroscopic information for nuclei lying within the 'Island of Inversion' remains scarce in particular for the very neutron rich nuclei due to the limitations imposed by the experimental facilities producing radioactive beams. With the Radioactive Ion Beam Factory (RIBF) [3-5] being recently commissioned, previously inaccessible nuclei are now within spectroscopic range. The presentation will report on the first in-beam γ-ray spectroscopy experiment performed at the RIBF, targeting the neutron rich nuclei 3^0-32Ne. The secondary beams, identified and selected by the BigRIPS spectrometer, were incident on thick C and Pb targets, thereby inducing fragmentation and Coulomb excitation reactions, respectively. De-excitation γ-rays were detected with the DALI2-array [6] and reacted particles were identified with the ZeroDegree spectrometer. Initial results of this experiment are presented, demonstrating the potential of the new RIBF facility.(author)

No abstract available

[en] With the RI Beam Factory at RIKEN being on the cusp to deliver the world's most intense radioactive ion beams at relativistic energies, a new γ-ray detection array has been proposed to exploit the new experimental possibilities coming along with it. The material LaBr₃(Ce) possesses an unprecedentedly high intrinsic energy resolution for scintillators of ≅2% at 1.3 MeV and is therefore well suited for high-resolution in-beam γ-ray experiments at relativistic energies. To minimize Doppler effects, the total array will comprise of up to one thousand individual crystals. It is intended to place the array around the secondary target area of the large acceptance fragment separator BigRIPS and use it either in a stand-alone mode or in addition to a reconfigured DALI2 array. Alternatively, the array will be used in a different configuration for stopped beam, delayed γ-ray decay experiments.

[en] The poorly known B(E2; 0⁺ → 2⁺) values of ¹¹²Sn and ¹¹⁴Sn have been measured to high precision. Two Coulomb excitation experiments were performed to determine the reduced transition probabilities relative to ¹¹⁶Sn in order to minimize the systematic errors. The obtained B(E2 ↑) values of 0.242(8) e²b² for ¹¹²Sn and 0.232(8) e²b² for ¹¹⁴Sn confirm the tendency of large B(E2 ↑) values for the lighter tin isotopes below the midshell ¹¹⁶Sn that has been observed recently in various radioactive ion beam experiments. (authors)

[en] The liquid-hydrogen target and TPC system MINOS has been combined with the DALI2 detector device for the first time at RIKEN-RIBF within the SEASTAR project. In the first experiment campaign, excited-state energies in neutron-rich Fe and Cr isotopes, as well as "7"8Ni have been measured. The RIKEN-RIBF cyclotrons delivered a 345 MeV/u "2"3"8U beam with an intensity of about 13 pnA, impinging on a Be target. Fission fragments were separated and identified using the BigRIPS spectrograph, and reaction products were analyzed using the ZeroDegree spectrograph behind the secondary target. First results on 2"+_1 and 4"+_1 energies give an indication for the location of the maximum of collectivity in the Fe and Cr isotopic chains. The new MINOS/DALI2 setup, experiment details, and first results on the Fe and Cr isotopes are presented.

[en] The in-beam gamma-ray spectroscopy of "6"8Fe is presented with two new observed transitions. The experiments were performed at RIKEN in the frame work of the first Shell Evolution And Search for 2"+ energy At RIBF (SEASTAR) experiment campaign. First, the experimental setup and the data analysis are introduced in details. Afterwards, the experimental method to identify single peaks by comparing with simulation is discussed. The preliminary inclusive cross section and state exclusive cross sections of "6"9Co(p,2p)"6"8Fe are derived and the level scheme of "6"8Fe is built. (author)

No abstract available