A heavy ion accelerator refers to an ion accelerator heavier than alpha particles, and sometimes it can also be used to accelerate protons. A large number of heavy ions can be accelerated to a very high speed, even close to the speed of light, and the high-speed heavy ions form heavy ion beams, which are used to carry out heavy ion physics research. China's first self-developed medical heavy ion accelerator successfully emerged. This means that heavy ion radiotherapy for cancer patients will no longer rely on foreign technical equipment.