Patent ID: 8357911

Claim:
A particle beam irradiation system comprising: a scanning electromagnet that scans a charged particle beam accelerated by an accelerator and has a hysteresis; a scanning power source that outputs an excitation current for driving the scanning electromagnet; a magnetic-field sensor that measures a magnetic field of the scanning electromagnet driven by the excitation current; and an irradiation control apparatus that controls the scanning power source, based on a measurement magnetic field measured by the magnetic-field sensor and target irradiation position coordinates of the charged particle beam, wherein the irradiation control apparatus is provided with an inverse map calculator that calculates a target magnetic field, based on the target irradiation position coordinates of the charged particle beam; and a controller that creates a command value for the excitation current, which is issued to the scanning power source, so as to make the magnetic-field error between the target magnetic field and the measurement magnetic field the same as or smaller than a predetermined threshold value, and that outputs the command value to the scanning power source.