Expérience GANILAligned fragment emission associated with peripheral and midperipheral dissipative collisions of 124Xe+124Sn at E/A = 50 MeV is examined. Binary decay of the excited projectile-like fragment (PLF∗) is correlated with significant velocity damping from the projectile velocity. Both a forward emission component, attributed to standard statistical emission, and a backward component are observed. The backward component arises from both statistical and dynamical decay processes. This backward component manifests a strong alignment with the direction of the PLF∗ velocity and is found to depend sensitively on the atomic number of the light fragment, ZL, and the velocity of the PLF∗. The yield of the backward component is significantly enhanced relative to the forward component. The composition of fragments emitted in the backward direction reveals that a correlation between alignment and neutron excess exists for fragments with Z < 8. From the measured asymmetry of the angular distributions, the angular distribution for dynamical fragment emission is deduced. Comparison with a schematic one-dimensional Langevin model allows extraction of both the magnitude and the dependence on ZL of the transient initial deformation of the PLF∗. Fragment emission times of the order of 0.25–1.5 × 10−21 s are extracted

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An atomic clock based on x-ray fluorescence yields has been used to estimate the mean characteristic time for fusion followed by fission in reactions 238U + 64Ni at 6.6  MeV/A. Inner shell vacancies are created during the collisions in the electronic structure of the possibly formed Z=120 compound nuclei. The filling of these vacancies accompanied by a x-ray emission with energies characteristic of Z=120 can take place only if the atomic transitions occur before nuclear fission. Therefore, the x-ray yield characteristic of the united atom with 120 protons is strongly related to the fission time and to the vacancy lifetimes. K x rays from the element with Z=120 have been unambiguously identified from a coupled analysis of the involved nuclear reaction mechanisms and of the measured photon spectra. A minimum mean fission time τ(f)=2.5×10(-18)  s has been deduced for Z=120 from the measured x-ray multiplicity.

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A direct and complete measurement of isotopic fission-fragment yields of 239 U has been performed for the first time. The 239 U fissioning system was produced with an average excitation energy of 8.3 MeV in one-neutron transfer reactions between a 238 U beam and a 9 Be target at Coulomb barrier energies. The fission fragments were detected and isotopically identified using the VAMOS++ spectrometer at the GANIL facility. This measurement allows to directly evaluate the fission models at excitation energies of fast neutrons, relevant for next-generation nuclear reactors. The present data, in agreement with model calculations, do not support the recently reported anomaly in the fission-fragment yields of 239 U and confirm the persistence of spherical shell effects in the Sn region at excitation energies exceeding the fission barrier by few MeV.

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The neutrons for science (NFS) facility is a component of SPIRAL-2, the new superconducting linear accelerator built at GANIL in Caen (France). The proton and deuteron beams delivered by the accelerator will allow producing intense neutron fields in the 100 keV-40 MeV energy range. Continuous and quasi-mono-kinetic energy spectra, respectively, will be available at NFS, produced by the interaction of a deuteron beam on a thick Be converter and by the 7Li(p,n) reaction on thin converter. The pulsed neutron beam, with a flux up to two orders of magnitude higher than those of other existing time-of-flight facilities, will open new opportunities of experiments in fundamental research as well as in nuclear data measurements. In addition to the neutron beam, irradiation stations for neutron-, proton- and deuteron-induced reactions will be available for cross-sections measurements and for the irradiation of electronic devices or biological cells. NFS, whose first experiment is foreseen in 2018, will be a very powerful tool for physics, fundamental research as well as applications like the transmutation of nuclear waste, design of future fission and fusion reactors, nuclear medicine or test and development of new detectors.