In this report, we consider the effect of radiation with radiation energy below the β -Ga 2 O 3 band-gap on the photoelectric characteristics of ultraviolet (UV) radiation detectors based on gallium oxide thin films. The gallium oxide film was deposited by radio frequency magnetron sputtering. Interdigital Ti/V electrodes were formed with an inter-electrode distance d = 30μm . The structures exhibit high values of photocurrent under irradiation with a wavelength of λ = 254 nm and intensity of 780μW /cm 2 . The detectors exhibit persistent photoconductivity after exposure to UV radiation. The presence of persistent conductivity is explained by the high concentration of traps in the Ga 2 O 3 film and their recharging under UV irradiation. Radiation with an energy quantum below the β -Ga 2 O 3 band-gap changes the charge state of trap centers in a gallium oxide film. This effect leads to an increase in photocurrent under UV exposure and increases the stability of detectors.