In this paper, the behavior of a silicon PiN diode exposed to a 14 MeV neutron beam has been studied. Three-dimensional electrothermal simulations have been performed with TCAD tools from Silvaco, taking advantage of the cylindrical symmetry of the unit cell. The numerical model has been validated by superimposing the numerical data with experimental data collected at the Frascati Neutron Generator during an irradiation test. A new approach is proposed by examining the effects of the ionic species that low-energy neutrons are able to generate by nuclear reaction interacting with silicon material, combining experimental characterization and numerical simulation. The study shows that the (α, 25 Mg) ion pair is the secondary particle that interacts most with the electric field inside the intrinsic region of the device. This interaction, at the critical cathode bias voltage, leads to a single event burnout of the diode as observed during irradiation campaigns and confirmed by numerical analysis.