The study of the radiation hardness of subterahertz radiation source from a Gunn diode oscillator and a multiplier, based on a semiconductor superlattice GaAs/AlAs was continued. The dependences of the output power on the frequency of a Gunn diode oscillator before and after neutron irradiation are experimentally measured. The dependence of the output power on the frequency of the source of subterahertz radiation to neutron radiation with fluences of 3.5·1012, 2.85·1013, 1014 cm-2 has been analytically estimated. Keywords: Radiation hardness, superlattice, Gunn diode, THz.