which type of ionising radiation has no charge?

The type of ionizing radiation that has no charge is gamma radiation. Gamma rays are high-energy electromagnetic waves with no mass and no electrical charge. They are indirectly ionizing because they interact with atoms by liberating electrons, which then cause ionization. X-rays also share these characteristics of no charge and being indirectly ionizing radiation. In contrast, alpha particles carry a positive charge, and beta particles carry a negative charge, while neutrons have no charge but are considered indirectly ionizing particles due to their interaction with nuclei producing charged particles. Thus, the key ionizing radiation type with no charge is gamma radiation (and also X-rays).