Orateur
Description
Nuclear fission is a key process in both nuclear structure studies and astrophysical nucleosynthesis. In particular, fission influences the production of the heaviest nuclei in the rapid neutron-capture (r-) process by limiting the maximum mass that can be reached. However, experimental information on the fission barriers of neutron-rich nuclei remains limited. Measurements of fission probabilities provide an important tool for constraining these barriers and investigating the influence of nuclear structure on the fission process.
The ISOLDE Solenoidal Spectrometer (ISS) enables studies of fission probabilities in inverse kinematics using radioactive ion beams and the (d,pF) transfer reaction. In this approach, transfer-like protons are detected in coincidence with fission fragments within a solenoidal magnetic field, allowing the fission probability to be determined as a function of excitation energy. In addition, coincident γ-ray measurements can be used to study the total γ-ray energy and multiplicity associated with the fission process.
As a first step towards measurements of neutron-rich actinides, the fission barrier of $^{233}$U has been investigated using this technique. Besides providing information relevant to the understanding of the fission process, this nucleus is also of interest in the context of the thorium fuel cycle. This presentation introduces the experimental setup and discusses preliminary results from the $^{233}$U measurement. The demonstrated methodology provides a basis for future studies of increasingly neutron-rich nuclei that are inaccessible using conventional experimental approaches.