Inverse kinematics (p, n) reactions studies using the WINDS slow neutron detector and the SAMURAI spectrometer

摘要

We have combined the low-energy neutron detector WINDS (Wide-angle Inverse-kinematics Neutron Detectors for SHARAQ) and the SAMURAI spectrometer at RIKEN Nishina Center RI Beam Factory (RIBF) in order to perform (p, n) reactions in inverse kinematics for unstable nuclei in the mass region around A ～ 100. In this setup, WINDS is used for detecting recoil neutrons and the SAMURAI spectrometer is used for tagging decay channel of heavy residue. The first experiment by using the setup was performed to study Gamow-Teller transitions from ~(132)Sn in April 2014. The atomic number Z and mass-to-charge ratio A/Q of the beam residues were determined from the measurements of time of flight, magnetic rigidity and energy loss. The obtained A/Q. and Z resolutions were σ_(A/Q) = 0.14% and σ_Z = 0.22, respectively. Furthermore, owing to the large momentum acceptance (50%) of SAMURAI, the beam residues associated with the γ, 1n and 2n decay channel were measured in the same magnetic field setting. The kinematic loci of the measured recoil neutron energy and laboratory angle are clearly seen. It shows that the excitation energy up to about 20 MeV can be reconstructed.