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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.

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.

International audience; 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.

The nuclei in the mass region A ≃125 lie between the spherical Sn nuclei(Z=50) and strongly deformed Ce nuclei(Z=58) and are therefore, transitional with respect to their shapes at low and high angular momenta. In this mass region, there exists a unique parity intruder orbital h11/2 which is accessible to both the protons and neutrons. These h11/2 nucleons have opposite deformation driving effects; neutrons drive the nucleus towards the oblate shape whereas the protons favour the prolate shape. Thus, the outcome of this interplay makes this region very interesting to study shape evolutions from lower to higher spins as the nucleus can have a prolate, an oblate or a triaxial shape depending on the alignment of the h11/2 nucleons[1].

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.

High-spin states in 123I were populated in the reaction 80Se(48Ca,p4n)123I at a beam energy of 207 MeV and gamma-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.

High-spin states in I-123 were populated in the reaction Se-80(Ca-48,p4n)I-123 at a beam energy of 207 MeV and gamma-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. DOI: 10.1103/PhysRevC.86.067305

he spectroscopic quadrupole moment of the T-1/2 = 9.4(5) ns isomer in Pb-193 at an excitation energy E-ex = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I-pi = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

Im Kontext der nuklearen Bedrohung durch Einzelpersonen oder terroristische Vereinigungen, bei der z.B. Spaltmaterial Verwendung findet (etwa in Form einer improvisierten nuklearen Anordnung), sind Methoden zur Detektion derartigen Materials von großer Bedeutung. Auf dem Weg zum Bau einer solchen Anordnung müsste das Material transportiert und gelagert werden, was durchaus komplexe Vorgehensweisen seitens der Terroristen erfordert. Es besteht die Hoffnung, dass diesen Personen dabei Fehler unterlaufen, die zur Möglichkeit der Detektion des Materials, etwa an Grenzstationen, führen. In diesem Fall sind hochempfindliche, teilweise mobile Detektionssysteme erforderlich, die das Spaltmaterial aufspüren können. Von besonderem Vorteil sind in diesem Zusammenhang Detektoren, die eine verdeckte Suche ermöglichen, wenn Täter z.B. das Material an öffentlichen Orten transportieren. Detektionssysteme und ihre Eignung für solche Aufgaben wurden entsprechend untersucht. Die so gewonnenen Erfahrungen werden vorgestellt.

The g factors of the 12+, 11-, and 8- isomeric states in 188Pb were measured using the time-differential perturbed angular distribution method as g(12+)=-0.179(6), g(11-)=+1.03(3), and g(8-)=-0.037(7). The g factor of the 12+ state follows the observed slight down-sloping evolution of the g factors of the i13/22 neutron spherical states with decreasing N. The g factors of the 11- and 8- isomers proposed as oblate and prolate deformed states, respectively, were interpreted within the rotational model, using calculated and empirical g factor values for the involved single-particle orbitals.

The feasibility of measuring g -factors using the TDPAD method applied to high-energy, heavy fragmentation products is explored. The 2623keV \ensuremathIπ=12+ isomer in 192Pb with τ = 1.57 μs has been produced using the fragmentation of a 1A GeV 238U beam. The results presented demonstrate for the first time that such heavy nuclei produced in a fragmentation reaction with a relativistic beam are sufficiently well spin-aligned. Moreover, the rather large value of the alignment, 28(10)% of the maximum possible, is preserved during the separation process allowing the determination of magnetic moments. The measured values of the lifetime, τ = 1.54(9) μs, and the g -factor, g = - 0.175(20) , agree with the results of previous investigations using fusion-evaporation reactions.

International audience; The Rare Isotope Spectroscopic INvestigation at GSI (RISING) project is a major pan-European collaboration. Its physics aims are the studies of exotic nuclear matter with abnormal proton-to-neutron ratios compared with naturally occurring isotopes. RISING combines the FRagment Separator (FRS) which allows relativistic energies and projectile fragmentation reactions with EUROBALL Ge Cluster detectors for $\gamma$ spectroscopic research. The RISING setup can be used in two different configurations. Either the nuclei of interest are investigated after being stopped or the heavy ions hit a secondary target at relativistic energies and the thereby occurring excitations are studied. For the latter case, MINIBALL Ge detectors and the HECTOR array are used in addition. Example achievements of the Fast Beam setup are presented and compared to various shell model calculations, while for the Stopped Beam setup initial results are shown.