Nuclear temperature of spectator source extracted by neutron spectra in ¹²⁴Sn,¹⁰⁷Sn + ¹²⁰Sn collisions at 600 MeV/nucleon

The properties of neutrons from spectator sources produced in 107, 124Sn + ¹²⁰Sn collisions at 600 MeV/nucleon are studied. The isospin-dependent quantum molecular dynamics (IQMD) model is used to describe the dynamical process of the fragmentation, and the statistical model GEMINI is applied to simulate the secondly decay of the pre-fragments. The differential cross section and multiplicity of the neutrons emitted from the spectator source are used to prove the feasibility of the model. The temperatures of the spectator source are extracted by two-source-fitting the transverse momentum distributions of the neutrons using the classical Maxwellian functions. The temperatures of the spectator sources extracted from calculations are consistent with the experimental data, those from the SMM model, and the isotopic temperature \(THeLi\). However, the participant source exhibits anomalously high temperatures. Our work suggests the possible model-errors of the IQMD+GEMINI model when describing the neutron emission from the participant source, which is of reference for the further development of the model.