Multinucleon-transfer reactions: a surrogate method for fission studies
By C. Rodríguez-Tajes - GANIL
In the last years, transfer reactions have been widely used to investigate neutron-induced fission for nuclei not accessible by neutron irradiation. This method consists in measuring the fission probability of the same compound nucleus as it would be produced by neutron capture, but using light transfer reactions as stripping or pick-up between hydrogen or helium beams and actinide targets close to the nuclei of interest. The validity of this approach relies on the hypothesis that the decay of the compound nuclei is independent of the formation process, which is nowadays a subject of intense debates.
We will present results from a recent experiment performed at GANIL (E516a), where we proposed to extend the surrogate method to heavy transfer reactions, using inverse kinematics. As compared to standard reactions, this technique makes possible the investigation of a broader collection of fissioning systems in a single experiment.
A number of fissioning systems was produced from multinucleon-transfer reactions between a 6.14 MeV/u 238U beam and a 100 µg/cm2 12C target, namely heavy actinides from U to Am, with excitation energies below 30 MeV. The energy and the angle of the target-like partner of the transfer reaction were measured in a double annular Si telescope (SPIDER). This information allowed a complete characterization of the different fissioning systems, in atomic number, mass and excitation energy. This seminar will be mainly devoted to the discussion of preliminary results from the SPIDER detector.