Simulation analysis of the photoneutron target for a white neutron source driven by a 40 MeV/40 kW electron linear accelerator

To enhance nuclear data measurement capabilities, the Shanghai Institute of Applied Physics (SINAP) of the Chinese Academy of Sciences plans to upgrade the TMSR Photo-Neutron Source Phase I (TPNS-I) facility, which was originally constructed in 2014. The upgraded facility, designated as TMSR Photo-Neutron Source Phase Ⅱ (TPNS-Ⅱ), will be driven by a 40 MeV electron beam to generate a high-flux white-spectrum neutron beam via photonuclear reactions. As an essential component of the facility, the photoneutron target must maintain structural integrity and thermal stability under sustained bombardment by such a high-energy, high-power electron beam. In this study, the target assembly was designed and optimized using the Monte Carlo method, yielding key parameters such as neutron yield, energy spectrum, and angular distribution. Furthermore, its thermal performance was evaluated using the ANSYS finite-element analysis software. The results indicate that the designed target assembly meets the heat dissipation requirements under irradiation by a 40 MeV / 40 kW incident electron beam, thereby providing a critical design basis for the upgrade project.