Nuclear equation of state studies with CSHINE

CSHINE is a compact spectrometer for heavy-ion experiment. After more than a decade of construction and upgrading, CSHINE experiments have completed several rounds on the Heavy Ion Research Facility at Lanzhou (HIRFL), China. Advanced detection technologies have been developed, and a series of physical results related to the equation of state of nuclear matter have been achieved. This study will introduce the key technologies of the series of CSHINE experiments, including the silicon strip detector telescope, parallel plate avalanche chamber, high-energy gamma array, and neutron array, etc.Meanwhile, based on the CSHINE experiments, we have made a series of progress in the research on the constraints of the symmetry energy of the equation of state of nuclear matter and the isospin transport phenomena in recent years. Among them, the isospin long-time scale relaxation phenomenon has been discovered through the angular distribution of the coalescence neutron richness of light charged particles, and the density-dependent parameter L of the symmetry energy has been constrained to be 33–61 MeV. Furthermore, by measuring the intensity correlation function of hydrogen isotopes, the emission time scale of protons has been determined to be 100 fm/c, and the result that neutron-rich particles are emitted earlier has been obtained.In order to determine whether there is an isospin correlation between two particles emitted successively in one heavy ion collision, a creative method of isobar analysis has been proposed, and the isospin “ping-pong" emission phenomenon has been observed, which is sensitive to nuclear symmetry energy. When considering the spatial distribution of isospin in fission events, through the angular distribution of the yield ratio of triton and ³He from out-of-fission-plane, the experimental phenomenon of the enhancement of neutron rich particle emission from out-of-fission-plane has been determined, which shows a significant symmetry energy effect. These results provide new approaches for the research on the equation of state of nuclear matter and isospin dynamics.