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The level structures of the N = 50 83As, 82Ge, and 81Ga isotones have been investigated by means of multi-nucleon transfer reactions. A first experiment was performed with the CLARA–PRISMA setup to identify these nuclei. A second experiment was carried out with the GASP array in order to deduce the γ-ray coincidence information. The results obtained on the high-spin states of such nuclei are used to test the stability of the N = 50 shell closure in the region of 78Ni ( Z = 28 ). The comparison of the experimental level schemes with the shell-model calculations yields an N = 50 energy gap value of 4.7(3) MeV at Z = 28 . This value, in a good agreement with the prediction of the finite-range liquid-drop model as well as with the recent large-scale shell model calculations, does not support a weakening of the N = 50 shell gap down to Z = 28 .

Objectif de l’etude La radiotherapie en conditions stereotaxiques est une technique innovante qui necessite une mise en place et une evaluation rigoureuse. Mise en œuvre dans notre centre en avril 2016, une analyse detaillee a ete realisee sur l’ensemble des tomographies coniques effectuees en fevrier 2017. Materiel et methode Le traitement a ete delivre en trois seances et cinq arcs conformationnels non coplanaire, par des rayons X de 6 MV sur un appareil True Beam (Varian), avec un collimateur multilames de 0,5 cm. Le controle du positionnement du patient a ete fait par deux cliches de basse energie (kV/kV), puis une tomographie conique. Le medecin a valide la position du patient a chaque seance. Le patient avait une contention personnalisee de type masque bivalve (Seemed). N’ayant pas de systeme de rayons X additionnel dans la salle de traitement, l’evaluation des decalages du patient entre le debut et la fin d’une seance de traitement a ete faite en comparant les tomographies coniques de debut et de fin de traitement. Cette evaluation a ete faite a posteriori. Resultats Nous avons classe les ecarts par rapport a l’os entre les tomographies coniques de debut et fin de traitement en deux niveaux : pas de decalage significatif (moins de 0,5 mm), ou mesure d’un decalage (plus de 0,5 mm). Pour 15 patients pris en charge et 45 seances de traitement, il a ete obtenu 21 seances sans decalage significatif (soit 47 %), 18 seances avec un decalage de plus de 0,5 mm (soit 40 %) et six seances non exploitables (soit 13 %). Pour les seances avec au moins un decalage de plus de 0,5 mm dans une direction, les decalages etaient en moyenne de 0,85 ± 0,4 mm longitudinalement, 0,8 ± 0,3 mm lateralement ; 0,74 ± 0,3 mm verticalement, avec des valeurs maximales relevees de 1,50 mm longitudinalement, 1,30 mm lateralement et 1,20 mm verticalement. Conclusion Nos resultats nous confortent sur notre choix de systeme de contention, la methodologie appliquee ainsi que des marges a appliquer entre le volume tumoral macroscopique et le volume cible previsionnels, fixees a 3 mm dans notre centre.

The de-excitation of medium mass nuclei 118,134Ba produced in fusion process of 78,86Kr on 40,48Ca targets at 10 AMeV is studied, in order to investigate the isospin dependence of the decay modes; the neutron enrichment of the compound nuclei is in fact expected to play an important role on the emission mechanisms, providing crucial information on fundamental nuclear quantities such as level density, fission barrier, viscosity and symmetry energy. The experiment was performed at INFN-LNS with the 4π multidetector for charged particles CHIMERA, used for the first time in this low energy regime, thanks to a suitable Pulse Shape Discrimination method for charge identification applied to the silicon detectors. Preliminary results show a different isotopic composition and relative enrichment for the same Z in the two systems. The yields of the Intermediate Mass Fragments (IMF, 3

This work has been supported by BMBF 06BN109, GA of Czech Republic 202/040791, MICINN-FPA2009-13377, CM-HEPHACOSS2009/ESP-1473 (Spain), the EC through the Eurons project Contracts No. RII3-CT-3/2004-506065, No. OTKA K68801, and No. K100835, the Bolyai Foundation, and by Romanian ANCS, CNCS UEFISCDI, Project No. PN-II-RU-TE-2011- 3-0051. R. B., A. B., F. N., and F. R. acknowledge the IN2P3/ CNRS support

The heavy-ion radiative capture reaction ${}^{12}$C(${}^{16}$O,$\ensuremath{\gamma}$)${}^{28}$Si has been studied at three energies ${E}_{\mathrm{c}.\mathrm{m}.}=8.5$, 8.8, and 9 MeV which are close to the Coulomb barrier. The weak radiative capture process has been identified by measuring the ${}^{28}$Si recoils in the highly selective 0${}^{\ensuremath{\circ}}$ spectrometer DRAGON at TRIUMF (Vancouver). The coincident $\ensuremath{\gamma}$ rays have been recorded in the associated BGO array. This has allowed a complete measurement of the $\ensuremath{\gamma}$ spectrum and the relative strength of all decay pathways. An important part of the decay through quasibound states close to the particle threshold and the feeding of bound states with particular deformation have been identified for the first time. Comparisons with Monte Carlo simulations allowed the extraction of the full experimental radiative capture cross section. Our results suggest an important contribution of spins ${J}^{\ensuremath{\pi}}={5}^{\ensuremath{-}}$ and 6${}^{+}$ in the entrance channel. The surprisingly large cross sections from 12 $\ensuremath{\mu}$b at ${E}_{\mathrm{c}.\mathrm{m}.}=8.5$ MeV to 25 $\ensuremath{\mu}$b at ${E}_{\mathrm{c}.\mathrm{m}.}=9.0$ MeV for the heavy-ion radiative capture process are discussed in terms of the interplay between statistical and structural aspects of the process.

The 12C+16O resonant radiative capture reaction has been studied at 5 bombarding energies between Elab = 15.4 and 21.4 MeV, around the Coulomb barrier, at the Triumf laboratory (Vancouver, Canada) using the Dragon 0{\deg} spectrometer and the associated BGO array. The most remarquable result is the previously unobserved decay path through 28Si doorway states of energies around 12 MeV leading to the measurement of new capture cross-sections. The feeding of specific, deformed states in 28Si from the resonances is discussed, as well as the selective feeding of 1^+ T=1 states around 11 MeV., Comment: Talk given by Sandrine Courtin at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

The 02+ state in Si34 has been populated at the GANIL-LISE3 facility through the β decay of a newly discovered 1 + isomer in Al34 of 26(1) ms half-life. The simultaneous detection of e +e - pairs allowed the determination of the excitation energy E(02+)=2719(3)keV and the half-life T 1/2=19.4(7)ns, from which an electric monopole strength of ρ2(E0)=13.0(0.9)×10 -3 was deduced. The 21+ state is observed to decay both to the 01+ ground state and to the newly observed 02+ state [via a 607(2) keV transition] with a ratio R(21+→01+/21+→02+)=1380(717). Gathering all information, a weak mixing with the 01+ and a large deformation parameter of β=0.29(4) are found for the 02+ state, in good agreement with shell model calculations using a new sdpf-u-mix interaction allowing np-nh excitations across the N=20 shell gap, This work has been supported by BMBF 06BN109, GA of Czech Republic 202/040791, MICINN-FPA2009-13377, CM-HEPHACOSS2009/ESP-1473 (Spain), the EC through the Eurons project Contracts No. RII3-CT-3/2004-506065, No. OTKA K68801, and No. K100835, the Bolyai Foundation, and by Romanian ANCS, CNCS UEFISCDI, Project No. PN-II-RU-TE-2011- 3-0051. R. B., A. B., F. N., and F. R. acknowledge the IN2P3/ CNRS support

In a recent experiment performed at Triumf using the Dragon 0° spectrometer and its associated BGO array, the complete γ-decay of the radiative capture channel below the Coulomb barrier has been measured for the first time. This measurement has been performed at two energies Ec.m. = 6.6 and 7.2 MeV. A selective contribution of the entrance spins 2+ and 3− has been evidenced which is consistent with existing results above the barrier.

The decay branchings of a resonance in the 12C(12C,γ)24Mg reaction at Ec.m. = 8.0 MeV have been studied with high resolution using the Gammasphere array. Radiative capture residues were discriminated from scattered beam and the dominant evaporation channels using the fragment mass analyzer coupled to a multistage Parallel Grid Avalanche Counter (PGAC)/ion chamber system. The clean selection of residues has allowed the population of excited states up to 10 MeV in 24Mg to be examined in detail. Strong feeding of an excited Kπ=0− band is observed. A Jπ = 4+assignment to the resonance is strongly favored.

Sub-barrier fusion cross sections of {sup 36}S + {sup 64}Ni have been measured down to {approx_equal}3 {mu}b. The logarithmic slope of the fusion excitation function has a steep rise in the barrier region with decreasing energy and saturates at lower energies. The data can be reproduced within the coupled-channels model using a Woods-Saxon potential with a large diffuseness. The slope saturation is analogous to what has been observed for {sup 36}S, {sup 48}Ca + {sup 48}Ca, while for heavier systems the slope increases steadily below the barrier.

Binary reactions at energies close to the Coulomb barrier received recently a significant boost thanks to the advent of the large solid angle magnetic spectrometer PRISMA coupled to the gamma array CLARA. In the present paper different aspects of the recent results of nuclear structure and reaction dynamics will be presented, focusing more closely on the reaction mechanism.

Charged-particle and $\ensuremath{\gamma}$ decays in $^{24}\mathrm{Mg}{}^{*}$ are investigated for excitation energies where quasimolecular resonances appear in $^{12}\mathrm{C}+^{12}\mathrm{C}$ collisions. Various theoretical predictions for the occurrence of superdeformed and hyperdeformed bands associated with resonance structures with low spin are discussed within the measured $^{24}\mathrm{Mg}{}^{*}$ excitation energy region. The inverse kinematics reaction $^{24}\mathrm{Mg}+^{12}\mathrm{C}$ is studied at ${E}_{\mathrm{lab}}(^{24}\mathrm{Mg})=130$ MeV, an energy that enables the population of $^{24}\mathrm{Mg}$ states decaying into $^{12}\mathrm{C}+^{12}\mathrm{C}$ resonant breakup states. Exclusive data were collected with the Binary Reaction Spectrometer in coincidence with Euroball IV installed at the Vivitron tandem facility at Strasbourg. Specific structures with large deformation were selectively populated in binary reactions, and their associated $\ensuremath{\gamma}$ decays studied. Coincident events associated with inelastic and $\ensuremath{\alpha}$-transfer channels have been selected by choosing the excitation energy or the entry point via the two-body $Q$ values. The analysis of the binary reaction channels is presented with a particular emphasis on $^{24}\mathrm{Mg}\text{\ensuremath{-}}\ensuremath{\gamma}$, $^{20}\mathrm{Ne}\text{\ensuremath{-}}\ensuremath{\gamma}$, and $^{16}\mathrm{O}$-$\ensuremath{\gamma}$ coincidences. New information (spin and branching ratios) is deduced on high-energy states in $^{24}\mathrm{Mg}$ and $^{16}\mathrm{O}$, respectively.

Resonances in light heavy‐ion collisions have been observed in systems with a small number of open channels. Very narrow resonances have been reported in the 24Mg+24Mg and 12C+12C cases for which the results of recent experiments on their decay modes will be presented. Special emphasis will be given to the 12C+12C reaction where weak absorption allows the observation of resonant and refractive effects over a large bombarding energy range. The nature of recently observed sub‐coulomb resonances will also be raised.

Resonances in the 12C(16O,γ)28Si radiative capture process at energies around the Coulomb barrier have been probed using the very selective 0° Dragon spectrometer at Triumf and its associated BGO γ‐array. For the first time the full level scheme involved in this process has been measured and shows previously unobserved γ‐decay to doorway states around 11 MeV in 28Si.

In recent years, a puzzling pattern has been observed in fusion cross sections well below the Coulomb barrier, characterized as a departure from the exponential‐like behavior predicted by standard coupled‐channels models, known as fusion hindrance. We report on recent fusion measurements performed at the Laboratori Nazionali di Legnaro, in particular the 48Ca+48Ca reaction down to the level of 0.6 μb. Unlike most recent results in this field, we do not observe the typical divergent behavior of the logarithmic derivative; but rather a sort of saturation, albeit at a larger value than predicted with a standard nucleus‐nucleus potential.

In a recent experiment performed at Triumf using the Dragon 0° spectrometer and its associated BGO array we have measured for the first time the full gamma decay of the radiative capture channel close to the Coulomb barrier. This measurement has been performed at 3 energies Ecm = 8.5, 8.8 and 9 MeV. We have extracted a radiative capture cross section more than five times larger than what had been previously observed. A selective contribution of the entrance spins 5− and 6+ has also been evidenced whereas 1− to 3− spins are predicted to be predominant by coupled‐channel calculations. At Ecm = 9 MeV, stronger structural behaviour appears which is characterised by a larger total cross section and also by the particularly strong feeding of the 28Si prolate 4+ state at 9.16 MeV. This level is explained by several models in terms of 12C‐16O cluster sub‐structure. Our data is compared to such cluster‐model predictions and the agreement is quite good.

The 12C(16O,γ)28Si radiative capture reaction has been studied at energies close to the Coulomb barrier at Triumf (Vancouver) using the Dragon spectrometer and its associated BGO array. It has been observed that the γ decay flux proceeds mainly via states around 10–11 MeV and via the direct feeding of the 28Si 31− (6879 keV) and 42+ (6888 keV) deformed states. A discussion is presented about this selective feeding as well as perspectives for the use of novel detection systems for the study of light heavy‐ion radiative capture reactions.

The fusion excitation function for 36S+48Ca with positive Q‐value for the compound nucleus formation, has been measured from near the barrier down to very low energies, where “fusion hindrance” may be expected. No evidence of hindrance shows up in the measured energy range. Coupled‐channels calculations have been performed with a large diffuseness parameter of the Wood‐Saxon potential, reproducing the data above and below the barrier.

The fusion excitation function of {sup 36}S+{sup 48}Ca has been measured from well above the barrier down to very small cross sections at sub-barrier energies. A steady decrease of the fusion cross sections is observed below the barrier with no pronounced change of slope. The logarithmic derivative saturates and does not reach the value expected for a constant astrophysical S-factor. The S-factor does not show any maximum in the measured energy range. Coupled-channels calculations using a Woods-Saxon potential have been performed.

The heavy-ion radiative capture reaction, {sup 12}C({sup 12}C,{gamma}), has been investigated at energies both on- and off-resonance, with a particular focus on known resonances at E{sub c.m.}=6.0, 6.8, 7.5, and 8.0 MeV. Gamma rays detected in a BGO scintillator array were recorded in coincidence with {sup 24}Mg residues at the focal plane of the DRAGON recoil separator at TRIUMF. In this manner, the relative strength of all decay pathways through excited states up to the particle threshold could be examined for the first time. Isovector M1 transitions are found to be a important component of the radiative capture from the E{sub c.m.}=6.0 and 6.8 MeV resonances. Comparison with Monte Carlo simulations suggests that these resonances may have either J=0 or 2, with a preference for J=2. The higher energy resonances at E{sub c.m.}=7.5 and 8.0 MeV have a rather different decay pattern. The former is a clear candidate for a J=4 resonance, whereas the latter has a dominant J=4 character superposed on a J=2 resonant component underneath. The relationship between these resonances and the well-known quasimolecular resonances as well as resonances in breakup and electrofission of {sup 24}Mg into two {sup 12}C nuclei are discussed.

A great deal of research work has been undertaken in the alpha-clustering study since the pioneering discovery, half a century ago, of 12C+12C molecular resonances. Our knowledge of the field of the physics of nuclear molecules has increased considerably and nuclear clustering remains one of the most fruitful domains of nuclear physics, facing some of the greatest challenges and opportunities in the years ahead. In this work, the occurence of "exotic" shapes in light N=Z alpha-like nuclei is investigated. Various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures are presented. Results on clustering aspects are also discussed for light neutron-rich Oxygen isotopes.

International audience; The heavyion radiative capture reaction 12C(16O,$\gamma$)28Si has been studied at three energies on( ELab = 20.0 and 21.2 MeV) and off( ELab = 20.7 MeV) resonance at Triumf (Vancouver) using the stateoftheart Dragon 0° spectrometer and its very efficient associated BGO $\gamma$ array. Intermediate states around Ex = 11.5 MeV, carrying a large part of the resonant flux have been observed for the first time in this system. The nature of those doorway states is discussed in terms of recently calculated cluster bands in 28Si. The results are compared to a recent similar investigation of the 12C(12C,$\gamma$)24Mg reaction.

The 24Mg + 24Mg reaction has been studied at the Legnaro Tandem at a CM bombarding energy of 45.7 MeV where a narrow and high spin resonance has been reported previously. The decay of the resonance into the inelastic and fusion-evaporation channels has been investigated. The ON and OFF resonance decay yields have been measured using, for the inelastic channels, the fragment spectrometer PRISMA and the γ array CLARA, and, for the fusion-evaporation channels, the Si array EUCLIDES and the γ array GASP The resonant effects observed in both experiments are discussed and it is suggested that the resonance populates a deformed 48Cr after a Jacobi shape transition.