| 摘要 |
PROBLEM TO BE SOLVED: To provide a septum electromagnet and a particle beam radiotherapy device that facilitate maintenance and can accurately control a track of a particle beam.SOLUTION: There is provided a method of controlling a septum electromagnet 1 provided with an auxiliary coil 5 such that current in mutually opposite circumferential directions flow at parts corresponding to a first part 3u and a second part 3d of a septum coil 3, the method including a step S10 of measuring a beam state including change in at least one of a beam width and a position of a particle beam passing downstream from a vacuum duct 2, a step S20 of calculating a kick angle or magnetic field intensity of an unnecessary magnetic field produced in the vacuum duct 2 on the basis of the beam state, and a step S30 of calculating a value of current made to flow to the auxiliary coil 5 so as to cancel the calculated kick angle or magnetic field intensity on the basis of a magnetic field measurement result or an electric field analysis result when the current is made to flow to the auxiliary coil 5. |
