Search

The elastic scattering in the reaction $$^{7}$$ 7 Li+$$^{208}$$ 208 Pb was investigated in the bombarding energy range from 25 to 39 MeV. The real and imaginary parts of the optical potential were analyzed by using a phenomenological potential. A dispersion relation analysis is presented in order to investigate the threshold anomaly effect. It is concluded that $$^{7}$$ 7 Li has an intermediate behavior between the tightly bound nuclei such as $$^{16}$$ 16 O and the loosely bound nuclei such as $$^{6}$$ 6 Li where the lack of the threshold anomaly is unambiguously observed. Reaction cross sections are also extracted from the elastic scattering data and its comparison with the ones of other systems has been performed to draw hints on the effect of the breakup channel.

The $^{86}\mathrm{Zr}$ nucleus, which has a low-lying level scheme characteristic of a transitional nucleus, presents, according to the existing electromagnetic transition data, a subunitary ${\mathrm{B}}_{4/2}=B(E2,{4}_{1}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})/B(E2,{2}_{1}^{+}\ensuremath{\rightarrow}{0}_{1}^{+})$ ratio, which is anomalously low for a nonmagic nucleus, as it is outside the range of the traditional collective models values. In order to check this anomaly, we performed new measurements of the lifetimes of its low-lying states, with the $\ensuremath{\gamma}$-ray coincident recoil distance Doppler shift method, using the ROSPHERE detector array. New lifetimes were determined for the positive-parity yrast states up to the ${10}^{+}$ one, and for the ${8}_{2}^{+},\phantom{\rule{0.16em}{0ex}}{5}_{1}^{\ensuremath{-}}$, and ${7}_{1}^{\ensuremath{-}}$ states. The newly determined values of the $B(E2)$ values for the ${2}_{1}^{+}$ and ${4}_{1}^{+}$ states characterize a nucleus with a moderate quadrupole deformation and are well described by the interacting boson model. The ratio ${B}_{4/2}=1.38(22)$ is no longer anomalous. The low $B(E2)$ value of the ${6}_{1}^{+}$ state indicates a noncollective structure.

The beta-decay of Zn-81 to the neutron magic N = 50 nucleus Ga-81, with only three valence protons with respect to Ni-78, was investigated. The study was performed at the ISOLDE facility at CERN by means of gamma spectroscopy. The 81Zn half-life was determined to be T-1/2 = 290(4) ms while the beta-delayed neutron emission probability was measured as P-n = 23(4)%. The analysis of the beta-gated gamma-ray singles and gamma-gamma coincidences from the decay of Zn-81 provides 47 new levels and 70 new transitions in Ga-81. The beta(-)n decay of Zn-81 was observed and a new decay scheme into the odd-odd Ga-80 nucleus was established. The half-lives of the first and second excited states of Ga-81 were measured via the fast-timing method using LaBr3(Ce) detectors. The level scheme and transition rates are compared to large-scale shell-model calculations. The low-lying structure of (81)Gais interpreted in terms of the coupling of the three valence protons outside the doubly magic Ni-78 core.

The level structure of La-130 has been investigated using the (121)sb(C-12, 3n) reaction with the ROSPHERE array at IFIN-HH, Bucharest. the level scheme was significantly extended with the observation of 45 new states and 100 new transitions. Several band structures have been identified and a clear connection with the lower-lying states has been established. A lifetime of tau = 3.6(2) ns has been measured for the 346-keV 6(-) state by the in-beam fast timing technique. the lifetimes of 18 high-spin states have been determined by applying the Doppler-shift attenuation method. the deformations derived from the experimental B(E2) transition strengths indicate distinct coexisting shapes at high spins in La-130. the experimental properties of both low- and high-spin states were compared with theoretical calculations performed in the frame of the two-quasiparticles-plus-rotor model. Two new negative-parity decoupled bands, with a deduced quadrupole deformation beta(2) = 0.150(15), were interpreted by coupling the proton in the 1/2[550] and 3/2[541] orbitals with the odd neutron occupying mainly the low-Omega orbitals from the d(3/2) and 5(1/2) states. A quadrupole deformation beta(2) = 0.220(17) was derived for a newly identified positive-parity decoupled band. This enhanced deformation was attributed to the involvement in the band configuration of the Omega = 1/2 (f(7/2), h(9/2)) intruder neutron orbital. the multiparticle configuration pi g(7/2)(h(11/2))(2) circle times nu (h(11/2)) was assigned to a high-spin negative-parity dipole band, based on the comparison of the experimental B(M1) transition strengths with values calculated by applying the geometrical model of Donau and Frauendorf., Ministry of Education and Research, Romania [PN-19-06-01-02], Authors are thankful to the FN Tandem staff of the Horia Hulubei National Institute of Physics and Nuclear Engineering for the good quality delivered beam. This work was supported by the Ministry of Education and Research, Romania, Contract No. PN-19-06-01-02.

This paper presents precision measurements of electromagnetic decay probabilities associated with electric dipole transitions in the prolate-deformed nucleus 183Re. The nucleus of interest was formed using the fusion evaporation reaction 180Hf(7Li,4n)183Re at a beam energy of 30 MeV at the tandem accelerator at the HH-IFIN Institute, Bucharest Romania. Coincident decay gamma rays from near-yrast cascades were detected using the combined HPGe-LaBr3 detector array ROSPHERE. The time differences between cascade gamma rays were measured using the LaBr3 detectors to determine the half-lives of the two lowest lying spin-parity 9/2- states at excitation energies of 496 and 617 keV to be 5.65(5) and 2.08(3) ns respectively. The deduced E1 transition rates from these two states are discussed in terms of the K-hindrance between the low-lying structures in this prolate-deformed nucleus.

The elastic scattering process for the nuclear reactions induced by the Radioactive Ion Beams 7Be and 8B on a 208Pb target was measured for the first time in the energy range around the Coulomb barrier. Extensive theoretical calculations within the framework of the optical model were performed. An excellent agreement between experimental data and theoretical predictions was achieved for the reaction 7Be + 208Pb, while a comprehensive understanding of the reaction dynamics induced by the more exotic projectile 8B is still far to be reached. Predictions of the cross section for the breakup for both systems will also be given., The 8B experiment was performed at RI Beam Factory operated by RIKEN Nishina Center and CNS, University of Tokyo. This work was supported by the Polish National Science Centre under Contract No. 2014/14/M/ST2/00738 (COPIN-INFN Collaboration), by JSPS KAKENHI (Nos. 16K05369, and 19K03883) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan and by the projects: CONACyT LN-294537 and DGAPA-PAPIIT IA103218.

The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9 MV Tandem accelerator. Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr3(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.

Lifetimes of several short-lived excited states in Nd138 were measured with the ROSPHERE array at IFIN-HH, Bucharest, using the recoil-distance Doppler shift technique following the Sb123(F19,4n) reaction. The resulting electromagnetic transition probabilities are compared to large-scale shell model calculations and to constrained Hartree-Fock-Bogoliubov calculations with the Gogny D1S interaction, configuration mixing, and a five-dimensional collective Hamiltonian formalism. The onset of collectivity in Nd isotopes below the N=82 shell closure and the deformation induced by the alignment of protons and neutron holes in the h11/2 orbitals are discussed.

WOS: 000450997800001, The lifetimes of the excited states belonging to the chiral-candidate doublet bands built on the pi h(11/2) circle times vh(11/12)(-1) configuration in La-130 have been measured by applying the Doppler-shift attenuation method and the in-beam fast timing technique. Excited states were populated in the Sb-121(C-12, 3n) reaction at a bombarding energy of 54 MeV. The 7(+) bandhead of the yrast band was identified as an isomeric state with a lifetime of tau(7(+)) = 0.38(7) ns Similar reduced transition probabilities B(M1) and B(E2) were found for the states with the same spin in the partner bands. The results revealed an even-odd spin dependence in the B(E2) values, whereas the B (M1) values vary nearly monotonically with increasing spin. The experimental properties of the doublet bands in La-130 are compared with theoretical calculations done in the frame of the two-quasiparticles-plus-triaxial-rotor model. The static chirality is not supported by the obtained data; however, chiral vibrations cannot be excluded., Scientific and Technological Research Council of Turkey (TUBTAK) [BIDEB-2219], Authors are thankful to the FN Tandem staff of the Horia Hulubei National Institute of Physics and Nuclear Engineering for the good quality of the delivered beam. S.A. acknowledges financial support from the Scientific and Technological Research Council of Turkey (TUBTAK) BIDEB-2219 Postdoctoral Research program.

In this contribution we describe the first results obtained for the investigation of the elastic scattering process in the reactions induced by the Radioactive Ion Beams 7Be and 8B on a 208Pb target at Coulomb barrier energies. The experimental data were analyzed within the framework of the optical model in order to extract the total reaction cross section. The comparison with data available in literature for reactions induced on 208Pb by light ions in the mass range A = 6-8 shows that the loosely-bound 8B has the largest reactivity.

This paper describes present capabilities of the new Target Preparation Laboratory constructed at Horia Hulubei National Institute for Physics and Nuclear Engineering, Bucharest-Magurele, Romania. Self-supporting or backed targets are produced in the laboratory, using thermal evaporation, electron-gun evaporation, sputtering or cold rolling techniques. At present, it is possible to prepare layers with a wide range of thicknesses from several tens of µg/cm2 to several hundreds of mg/cm2. As an example, we briefly describe a 40Ca target preparation.

States in the astrophysically important $^{19}\mathrm{Ne}$ nucleus have been populated directly using the $^{15}\mathrm{O}(\ensuremath{\alpha},\phantom{\rule{0.16em}{0ex}}\ensuremath{\alpha})^{15}\mathrm{O}$ reaction with a radioactive $^{15}\mathrm{O}$ beam. Due to the challenges involved, this represents the first such $^{15}\mathrm{O}$ measurement with high resolution and the first dedicated to exploring the cluster structure. This measurement comprises three experiments: the first to develop the $^{15}\mathrm{O}$ radioactive beam, the second the resonant scattering study, and the third to measure the precise energy loss of O ions in $^{4}\mathrm{He}$ to reduce systematic uncertainties. The results show evidence for $^{15}\mathrm{O}+\ensuremath{\alpha}$ cluster structure which could explain earlier results pointing to the increased $\ensuremath{\alpha}$ branching ratio in the astrophysical reaction rate for high-spin near-threshold resonances. Absolute differential cross sections have been measured. Additionally, spins, parities, and partial decay widths, essential for nuclear reaction-rate calculations, have been extracted using an $R$-matrix analysis.

The existence of two close-lying nuclear states in ⁷³Ga has recently been experimentally determined: a 1/2⁻ spin-parity for the ground state was measured in a laser spectroscopy experiment, while a J_π = 3/2⁻ level was observed in transfer reactions. This scenario is supported by Coulomb excitation studies, which set a limit for the energy splitting of 0.8 keV. In this work, we report on the study of the excited structure of ⁷³Ga populated in the β decay of ⁷³Zn produced at ISOLDE, CERN. Using β-gated, γ-ray singles, and γ –γ coincidences, we have searched for energy differences to try to delimit the ground-state energy splitting, providing a more stringent energy difference limit. Three new half-lives of excited states in ⁷³Ga have been measured using the fast-timing ;method with LaBr₃(Ce) detectors. From our study, we help clarify the excited structure of ⁷³G and we extend the existing ⁷³Zn decay to ⁷³Ga with 8 new energy levels and 35 γ transitions. We observe a 195-keV transition consistent with a γ ray de-exciting a short-lived state in the β-decay parent ⁷³Zn.

A search for shape isomers in the ^{66}Ni nucleus was performed, following old suggestions of various mean-field models and recent ones, based on state-of-the-art Monte Carlo shell model (MCSM), all considering ^{66}Ni as the lightest nuclear system with shape isomerism. By employing the two-neutron transfer reaction induced by an ^{18}O beam on a ^{64}Ni target, at the sub-Coulomb barrier energy of 39 MeV, all three lowest-excited 0^{+} states in ^{66}Ni were populated and their γ decay was observed by γ-coincidence technique. The 0^{+} states lifetimes were assessed with the plunger method, yielding for the 0_{2}^{+}, 0_{3}^{+}, and 0_{4}^{+} decay to the 2_{1}^{+} state the B(E2) values of 4.3, 0.1, and 0.2 Weisskopf units (W.u.), respectively. MCSM calculations correctly predict the existence of all three excited 0^{+} states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 0_{4}^{+} to the spherical 2_{1}^{+} state, although overestimating its value. This result makes ^{66}Ni a unique nuclear system, apart from ^{236,238}U, in which a retarded γ transition from a 0^{+} deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior.

The scattering process of the Radioactive Ion Beam 7 Be from a 208 Pb target was measured at three near-barrier energies. The quasi-elastic angular distributions were analyzed within the framework of the optical model to extract the reaction cross sections. The results are compared with those obtained for the reactions induced by the mirror projectile 7 Li and by the lightest particle-stable lithium isotope 6 Li on the same target. The angular distributions for the production of the two 7 Be constituent clusters, namely 3 He and 4 He, were also measured. In agreement with what observed for the interaction of 7 Be with lighter targets, the production of the heavier helium isotope resulted to be much more abundant than that of its lighter counterpart.

The elastic scattering excitation function for 15O on 4He was measured - for the first time - by using the Inverse Kinematic Thick Target scattering method. The obtained spectrum was analysed in an R-matrix framework providing spectroscopic information for several states in the excitation energy of the nucleus 19Ne from 4.8 to 9 MeV. Eight of them are newly observed states. The set-up and the experimental technique will be described in detail and the results will be shown and discussed. European Unions Horizon 2020 659744

Cross sections for 147,149 Sm(p,n) 147,149 Eu and 147,149 Sm(p, γ ) 148,150 Eu were measured using the activation method. The results are compared to the predictions of the Hauser-Feshbach statistical model. Different γ -ray strength functions have been tested against the experimental values. In the case of 150 Eu, in order to reproduce the experimental isomeric population cross sections, various scenarios for unknown branching ratios of certain discrete states have been discussed. The results provide constraints for the optical model parameters dedicated to this insufficiently known area of isotopes. Such cross sections for (p, γ ) reactions at energies below the Coulomb barrier are valuable for p -process nucleosynthesis calculations.

We developed a Monte-Carlo code for describing the reaction kinematics of the two-body direct processes employed of the EXOTIC beam-line of the Laboratori Nazionali di Legnaro (LNL) for the production of light weakly bound radioactive ion beams at energies of a few MeV/u. The program calculates the phase-space distribution of both primary and secondary beams at the target exit and uses these quantities to optimize the secondary beam selection with the EXOTIC spectrometer. The calculations have been performed and compared with the available experimental data for two reactions: (1)H(2)((17)O, (17)F)n and (3)He((6)Li, (8)B)n. (c) 2008 Elsevier B.V. All rights reserved.

The EXPADES (EXotic PArticle DEtection System) detector array consists of 16 Double Side Silicon Strip Detectors (DSSSD) with active areas of 64 × 64 mm 2 , arranged in 8 ΔE (40/50 μm)–E (300 μm) telescopes. All detector faces are segmented into 32 × 2-mm wide strips, ensuring a 2 × 2 mm 2 pixel configuration. Eight ionization chambers can be alternatively used as ΔE stages or, if needed, as an additional third layer for more complex triple telescopes. The signals from silicon ΔE layers and from ionization chambers are read by standard electronics, while innovative 32-channel ASIC chips are employed for the readout of the E stages. The results of off-line tests with alpha sources and from the first in-beam experiment with a 17 O beam are presented.

The lifetime $\ensuremath{\tau}({0}_{2}^{+})$ of $^{152}\mathrm{Gd}$ has been measured using fast electronic scintillation timing (FEST) with an array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (${\mathrm{LaBr}}_{3}$) detectors. $^{152}\mathrm{Gd}$ was produced via an $(\ensuremath{\alpha},n)$ reaction on a gold backed $^{149}\mathrm{Sm}$ target. The measured lifetime of $\ensuremath{\tau}({0}_{2}^{+})=96(6)\phantom{\rule{4pt}{0ex}}\mathrm{ps}$ corresponds to a reduced transition strength of $B(E2;{0}_{2}^{+}\ensuremath{\rightarrow}{2}_{1}^{+})=111(7)$ W.u. and an $E0$ transition strength of ${\ensuremath{\rho}}^{2}(E0)=39(3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ to the ground state. This result provides experimental support for the validity of a correlation that would be a novel indicator for a quantum phase transition (QPT).

This work aims at investigating the projectile binding energy influence on the reaction dynamics, introducing new results and new data analysis methods in order to overcome some typically encountered problems, such as the identification of reaction products differing by few mass units and the discrimination of direct reaction processes. The $^{17}\mathrm{O}+^{58}\mathrm{Ni}$ collision was studied at five near-barrier energies employing a compact experimental setup consisting of four double-sided silicon strip detectors (DSSSDs). Different reaction processes, namely the elastic and inelastic scattering and the $1n$ stripping, were discriminated by means of a detailed analysis of the experimental energy spectra based on Monte Carlo simulations. The elastic scattering angular distributions were investigated within the framework of the optical model using Woods-Saxon and double-folding potentials. The total reaction cross sections were extracted and the reduced cross sections compared with those obtained for $^{17}\mathrm{F}$ (${S}_{p}=0.600$ MeV), the mirror nucleus of $^{17}\mathrm{O}$ (${S}_{n}=4.143$ MeV), and for the tightly bound $^{16}\mathrm{O}$ projectile. The $^{17}\mathrm{O}+^{58}\mathrm{Ni}$ total reaction cross sections were larger than those for $^{16}\mathrm{O}$ on the same target at the lowest energies studied, becoming identical, within errors, as the incident energy increased above the Coulomb barrier. This behavior was related to a strong contribution from the $1n$-stripping channel at the lowest energies.

The $1{i}_{\frac{13}{2}}\ensuremath{\rightarrow}1{h}_{\frac{9}{2}}\phantom{\rule{0.16em}{0ex}}(M2)$ and $3{s}_{\frac{1}{2}}\ensuremath{\rightarrow}2{f}_{\frac{7}{2}}\phantom{\rule{0.16em}{0ex}}(E3)$ reduced proton transition probabilities in $_{83}^{209}\mathrm{Bi}$ have been determined from the direct half-life measurements of the ${\frac{13}{2}}_{1}^{+}$ and ${\frac{1}{2}}_{1}^{+}$ states using the Romanian array for $\ensuremath{\gamma}$-ray SPectroscopy in HEavy ion REactions (RoSPHERE). The ${\frac{13}{2}}_{1}^{+}$ and ${\frac{1}{2}}_{1}^{+}$ states were found to have ${T}_{\frac{1}{2}}=0.120(15)$ ns and ${T}_{\frac{1}{2}}=9.02(24)$ ns respectively. Angular distribution measurements were used to determine an $E3/M2$ mixing ratio of $\ensuremath{\delta}=\ensuremath{-}0.184(13)$ for the 1609 keV $\ensuremath{\gamma}$-ray transition deexciting the ${\frac{13}{2}}_{1}^{+}$ state. This value for $\ensuremath{\delta}$ was combined with the measured half-life to give reduced transition probabilities of $B(E3,{\frac{13}{2}}_{1}^{+}\ensuremath{\rightarrow}{\frac{9}{2}}_{1}^{\ensuremath{-}})=12(2)\ifmmode\times\else\texttimes\fi{}{10}^{3}\phantom{\rule{4.pt}{0ex}}{e}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{fm}}^{6}$ and $B(M2,{\frac{13}{2}}_{1}^{+}\ensuremath{\rightarrow}{\frac{9}{2}}_{1}^{\ensuremath{-}})=38(5){\ensuremath{\mu}}_{N}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{fm}}^{2}$. These values are in good agreement with calculations within the finite Fermi system. The extracted value of $B(E3,{\frac{1}{2}}_{1}^{+}\ensuremath{\rightarrow}{\frac{7}{2}}_{1}^{\ensuremath{-}})=6.3(2)\ifmmode\times\else\texttimes\fi{}{10}^{3}\phantom{\rule{4.pt}{0ex}}{e}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{fm}}^{6}$ can be explained by a small ($\ensuremath{\sim}6%$) admixture in the wave function of the ${\frac{1}{2}}_{1}^{+}$ state.

We describe the experimental set-up of the Radioactive Ion Beam (RIB) in-flight facility EXOTIC consisting of: (a) two position-sensitive Parallel Plate Avalanche Counters (PPACs), dedicated to the event-by-event tracking of the produced RIBs and to time of flight measurements and (b) the new high-granularity compact telescope array EXPADES (EXotic PArticle DEtection System), designed for nuclear physics and nuclear astrophysics experiments employing low-energy light RIBs. EXPADES consists of eight Δ E – E res telescopes arranged in a cylindrical configuration around the target. Each telescope is made up of two Double Sided Silicon Strip Detectors (DSSSDs) with a thickness of 40/60 μm and 300 μm for the Δ E and Eres layer, respectively. Additionally, eight ionization chambers were constructed to be used as an alternative Δ E stage or, in conjunction with the entire DSSSD array, to build up more complex triple telescopes. New low-noise multi-channel charge-sensitive preamplifiers and spectroscopy amplifiers, associated with constant fraction discriminators, peak-and-hold and Time to Amplitude Converter circuits were developed for the electronic readout of the Δ E stage. Application Specific Integrated Circuit-based electronics was employed for the treatment of the Eres signals. An 8-channel, 12-bit multi-sampling 50 MHz Analog to Digital Converter, a Trigger Supervisor Board for handling the trigger signals of the whole experimental set-up and an ad hoc data acquisition system were also developed. The performance of the PPACs, EXPADES and of the associated electronics was obtained offline with standard α calibration sources and in-beam by measuring the scattering process for the systems 17O+58Ni and 17O+208Pb at incident energies around their respective Coulomb barriers and, successively, during the first experimental runs with the RIBs of the EXOTIC facility.

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

We report on the measurement of the half-life of the yrast I π = 5 − state in the transitional nucleus 136 Ce using a combined HPGe-LaBr3(Ce) scintillator gamma-ray detection array. The measured value for the E 1 decay is approximately half a nanosecond, which corresponds to an E 1 decay strength of approximately 2 × 10 − 6 Wu. This value is in line with single-particle type E 1 decays in this mass region and suggests no sign of additional K-hindrance associated with axially symmetric quadrupole deformations observed for lighter cerium isotopes.

Low-energy isomeric states of 86Y were populated in the reaction 73Ge + 16O at 57MeV and were investigated by means of delayed n $ \gamma$ and $ \gamma$ $ \gamma$ coincidences. A half-life of 70(7)ns was measured for the 5- state at 208keV, yielding an exceptionally small B(M1) value of 2.0(7)×10-5 W.u. and a B(E2) value of 0.34(+24 -13) W.u. For the other three known isomeric states at 218, 243, and 302keV, the half-lives extracted from the present experimental data are in very good agreement with previous measurements. Given the newly observed isomeric character of the 5- 208keV state, the re-analysis of earlier experimental data on the 302keV isomer led to a new spin-parity assignment, 6+, for this state. In addition, this re-evaluation provided two g -factors, -0.083(3) and +0.63(2) , for the 208 and 302keV states, respectively. The results are discussed in terms of spherical-shell model calculations performed with a truncated space of configurations built on the f 5/2 , p 3/2 , p 1/2 , and g 9/2 valence orbitals. Effective spin, orbital, and “tensor” g -factors were determined empirically for protons and neutrons in the considered configuration space.

We present a new study of the low-lying states in 124 Te nucleus by γ-ray spectroscopy following 124 I β+/ε decay. The β radioactive sources were produced in the 124 Te ( p, n )124 I reaction induced by 11 MeV protons, delivered by the Bucharest FN Tandem Accelerator. The γ-rays were measured in a low background area with three large volume HPGe detectors. A total number of 276 milion double coincidence events were recorded in a six-day run. Most of the gamma line intensities previously measured were confirmed with improved accuracy and several gamma lines were obtained for the first time. Our results, combined with those from a recent ( n , γ) study are compared with the predictions of the E(5) critical point symmetry model and numerical IBA-1 model calculations at the critical point of the U(5)–O(6) phase transition.

The energy and angular distributions of $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$ ions produced in the $^{7}\mathrm{Be}\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}^{58}\mathrm{Ni}$ reaction at a bombarding energy of 22 MeV have been measured for the first time. The yield of the heavier helium isotope was four to five times more abundant than that of its lighter counterpart, ruling out the possibility that in this energy range the $^{7}\mathrm{Be}$ reaction dynamics is dominated by the exclusive breakup process $^{7}\mathrm{Be}\phantom{\rule{4pt}{0ex}}\ensuremath{\rightarrow}{\phantom{\rule{4pt}{0ex}}}^{3}\mathrm{He}\phantom{\rule{4pt}{0ex}}+\phantom{\rule{4pt}{0ex}}^{4}\mathrm{He}$ (${S}_{\ensuremath{\alpha}}=1.586$ MeV). Extensive kinematic and theoretical calculations suggest that the $^{3}\mathrm{He}$ ions mostly originate from the $^{4}\mathrm{He}$-stripping process and the $^{4}\mathrm{He}$ production is mainly triggered by the fusion-evaporation channel. The role played by the breakup, $^{3}\mathrm{He}$-stripping, $1n$-stripping, and $1n$-pickup processes is also discussed.

The low-lying positive- and negative-parity states in $^{168}\mathrm{Yb}$ have been investigated by means of the $(\ensuremath{\alpha},2\mathrm{n}\ensuremath{\gamma})$ fusion evaporation reaction. Using the coincidence method, the level scheme was corrected and extended up to 3 MeV, for both the positive- and negative-parity states. Using the new branching ratios determined in the present experiment, the $K$ quantum number was proposed for two negative-parity bands by direct comparison with the Alaga rule. Like in some other nuclei, one negative-parity band was established, decaying predominantly to the $\ensuremath{\gamma}$-vibrational band. In a second experiment, the lifetimes of the low-lying excited states up to ${J}^{\ensuremath{\pi}}={6}^{+}$ in the ground-state band were measured by using the in-beam fast-timing method with the Bucharest mixed high-purity germanium (HPGe) and ${\mathrm{LaBr}}_{3}$:Ce detector array using the triple-$\ensuremath{\gamma}$ coincidence method. Reduced $E2$ transition probabilities were extracted from the measured lifetimes and compared with the corresponding observables in neighboring isotopes, showing a smooth behavior with increasing mass. The positive- and negative-parity states as well as $E1$ and $E2$ transition probability ratios revealed by these experiments are compared with the interacting boson model in the $sd$ and $spdf$ boson space, and with the confined beta-soft rotor model, and are found to be in good agreement.

The half-lives o fthe I=5- and 7- yrast stateys with Ex=1978 kev and Ex=2307 keV in the N=78 isotone 136Ce have been measured to be 496(23) ps and 270(24) ps respectively , using the concident fast-timing spectroscopy technique following population by a 124Sn(16O,4n) fusion-evporation reaction at an incident beam energy of 68 MeV.

We studied the reaction dynamics induced at Coulomb barrier energies by the weakly-bound Radioactive Ion Beam 7Be (Sα = 1.586 MeV) on medium-mass (58Ni) and heavy (208Pb) targets. The experiments were performed at INFN-LNL (Italy), where a 2-3×105 pps 7Be secondary beam was produced with the RIB in-flight facility EXOTIC. Charged reaction products were detected by means of high-granularity silicon detectors in rather wide angular ranges. The contribution presents an up-to-date status of the data analysis and theoretical interpretation for both systems. European Commission, Seventh Framework Programme 600376

In the framework of the EURISOL project, the production of neutron-rich isotopes of rubidium and cesium has been studied. The intensities of mass-separated beams of rubidium and cesium isotopes generated from a thick 238 UC x target connected to a surface ionizer have been measured. The release properties of 140 Cs and 91 Rb have been investigated. The obtained results allowed us to determine the relative fission yields of rubidium and cesium isotopes with high accuracy.

In the context or the design of an intense source of low and intermediate energy, neutrons, the angular and energy distributions of neutrons produced in the interaction of 90 MeV protons in a C-12 target, in which the protons are stopped, have been measured by time-of-flight and activation techniques, As compared to C-12 the yield is less than a factor two higher, while it is somewhat less than for a Be-9 target. (c) 2005 Elsevier B.V. All rights reserved.

We have studied the elastic scattering of the exotic 17 F nuclei from 208 Pb at Coulomb barrier energies. For the measurement we used a new detector array with pixel structure and a large solid angle. Optical potential analysis shows that 17 F has an imaginary potential much less deep than 19 F. Information on the exclusive 17 F breakup cross section has been deduced too.

The subbarrier fusion cross sections with radioactive ion beams in the systems 10,11 Be+ 209 Bi have been measured and compared also with the stable system 9 Be+ 209 Bi. All three cross sections are similar within experimental accuracy; this is somehow unexpected since, in particular, the fusion process with 11 Be should be influenced by its halo structure and small binding energy and could behave in a different way from the other two Be isotopes, in particular from 10 Be, well bound. Extensive calculations were undertaken within the formalism of continuum discretized coupled channel ( CDCC ) that considered only the coupling to two-body breakup, into n +core, of the projectile with excitation to continuum up to 10 MeV. The results are in agreement with the 11,10 Be experimental data except at low energy where the cross sections could be influenced by target/projectile collective excitations. The CCFULL theoretical approach, compared to CDCC , seems to reproduce better the subbarrier region and worse the above barrier one. The 9 Be cross sections are all underestimated by the CDCC approach while are well reproduced by CCFULL calculations. This suggests that, in this last case, the schematization of the breakup process into 2 only fragments maybe is not adequate and/or other excitations, properly handed by the CCFULL code, could be relevant.

In the frame of the R&D program for the SPES project of the Legnaro Laboratories, the production yields of Rb, In and Cs isotopes have bean measured at the synchrocyclotron of the Petersburg Nuclear Physics Institute (PNPI) of Gatchina (Russia). Production yields for direct proton fission and neutron-induced fission on a high-density UC2 powder target are compared. The overall efficiencies as a function of the target temperature have been measured.

Cross-sections for the production of neutron-rich nuclei obtained by neutron-induced fission of natural uranium have been measured. The neutrons were generated by bombarding a 13C target with 55 MeV protons. The results, position of the maximum in the (Z, A)-plane, width and magnitude, are very comparable with those where the neutrons are generated by bombardment of natural 12C graphite with 50 MeV deuterons. Depending on the geometry of the converter/target assembly the isotope yields, however, are a factor of 2-3 lower due to less efficient production of neutrons per primary projectile, especially at small forward angles.

Online tests of uranium carbide targets of different density 11 and 1.25 g/cm3 coupled with a new type of high temperature electron beam ion source at a temperature of (2050–2300 °C) have been carried out. The yields of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements such as Pb, Bi, Po and some others have been measured. Comparisons of the yields of Ag, In and Sn isotopes from tested targets are presented. In the temperature interval of (2100–2130 °C) the delay times for Ag and In were measured. The integral online production efficiency from the target – ion source unit estimated in the range (0.2–10%) for different nuclides.

A new type of a high temperature electron beam ion source (HTEBIS) with a working temperature up to 2500 °C was developed for production of single charge ions of practically all elements. Off-line tests and on-line experiments making use of the developed ion source coupled with uranium carbide targets of different density, have been carried out. The ionization efficiency measured for stable atoms of many elements varied in the interval of 1–6%. Using the HTEBIS, the yields and on-line production efficiency of neutron rich isotopes of Mn, Fe, Co, Cu, Rh, Pd, Ag, Cd, In, Sn and isotopes of heavy elements Pb, Bi, Po and some others have been determined. The revealed confinement effect of the ions produced in the narrow electron beam inside a hot ion source cavity has been discussed.

High-spin states in the 97Tc nucleus have been studied by in-beam γ-ray spectroscopy with the reaction 82Se(19F,4nγ) at 68 MeV incident energy. Excited states have been observed up to about 8 MeV excitation and spin 43/2. The observed level scheme is compared with results of shell model calculations.

We studied the elastic scattering process for the system (17)F + (58)Ni at two colliding energies slightly above the Coulomb barrier. The experimental data were analyzed within the framework of the optical model to investigate the effects of the projectile small binding energy (S(p) = 600 keV) on the reaction dynamics. We found that in this energy range the "reduced" reaction cross section for the system (17)F + (58)Ni is rather similar to that induced by the interaction of tightly-bound (16)O nuclei on the same target. Nuclear Physics A

The interaction of loosely bound (S p = 600 keV) 17F ions with a 208Pb target was studied at E lab = 86 MeV, below the Coulomb barrier, by measuring the differential cross-section for the quasi-elastic scattering and the cross-section for the exclusive breakup process 17F $ \rightarrow$ 16O + p . The small reaction and exclusive breakup cross-sections confirm the small reactivity of this system, even at low energy, and indicates that the 17F small binding energy plays a minor role in the reaction dynamics.

Total neutron yields resulting from the proton bombardment of a thick 13 C target have been measured for 30 MeV protons. Absolute intensities, angular distributions and energy spectra of neutrons have been obtained by the time-of-flight technique where the detectors provided continuous coverage from 0° to 120°. Resonances have been found, some of which can be attributed to known states in 14 N. A total yield of 0.022(3) n/p was observed with a slight angular anisotropy towards forward angles. The measured yields are compared to the neutron yields produced by using deuterons on thick 12 C and 9 Be targets.

Clustering phenomena are well known in nuclear physics for stable nuclei, both α-conjugate (N=Z, A=2N), like8Be,16O,20Ne, and non-α-conjugate, like6Li and7Li. In general, it is expected that light exotic nuclei may also exhibit cluster behavior. Moving out of the valley of stability configurations can be found where at least one of the clusters is unbound or weakly bound, thus not satisfying the strong internal correlation requirement of classical clusters. This is so-called exotic clustering. The study of such systems presents many difficulties, due, mainly, to the low intensities typical of radioactive ion beams. Therefore, few significant experimental studies have been performed so far. In this work we searched for α-cluster states in19Ne above its α-decay threshold measuring, for the first time, the15O(4He,4He) elastic scattering excitation function. Moreover, this study classified low-energy states in Ne in the astrophysically important region in this HCNO-break-out nucleus. European Unions Horizon 2020 659744

A new facility, named EXOTIC, for the in‐flight production of light low‐energy weakly bound Radioactive Ion Beams (RIBs) is now fully operational at the Laboratori Nazionali di Legnaro (LNL) of the INFN. In this contribution we will present the facility, the Monte‐Carlo code we developed to properly describe the reaction dynamics inside the production target, the experimental results achieved and a list of possible RIBs delivered from the facility EXOTIC in the next future.