New detector system for a (p, pN) reaction in inverse kinematics

Anomalous phenomena have been observed in neutron-rich nuclei. In order to understand the phenomena, the weakly bound states have been extensively studied. On the other hand, the deeply bound states have not been investigated. Therefore, we plan to systematically measure the physical quantities of the deeply bound states by means of a (p, pN) reaction. The experiment will be performed, using the SAMURAI spectrometer, at RIKEN-RIBF.

In this project, we first performed a simulation using GEANT4 and optimized the experimental conditions. Then, based on the results, we developed following equipment necessary for the experiment. The first is a uniform 5-mm-thick solid hydrogen target. We constructed a cryostat and made a solid hydrogen target. The second is two large NaI (Tl) calorimeters which are used to measure total energy of recoil protons. We evaluated performance of the manufactured detector. The third is 64 plastic scintillator bars to measure time of flight of knockout nucleons. We studied stability of the PMT gain under the leakage magnetic field from the SAMURAI magnet.

In this talk, I will describe the outline of the experimental setup and the details of the development.