Halide perovskites are promising materials for optoelectronics with an attractive radiation resistance property. In this article, we study the effect of 30 keV Ga⁺ ion irradiation on the photoluminescence (PL) of CsPbBr₃ halide perovskite single crystals. The high crystal quality and liquid helium temperature studies make it possible to distinguish the radiation-defect-related PL band. A model to explain the band shifts with radiation dose and pulsed pump intensity has been developed. Bright defect PL allows the visualization of the irradiated areas using PL mapping. Manipulation of optical properties using focused ion beams opens wide opportunities for halide perovskite nanofabrication for optoelectronics.