Charged particle beam extraction method using pulse voltage

An accelerator including an injection apparatus of charged particles, a synchrotron which accelerates the charged particles by a high-frequency accelerating cavity, an emission apparatus of the charged particles, and a charged particle beam utility line,

• the accelerator further comprising, on a design orbit of a circulating charged particle beam, a pulse voltage generation apparatus which applies a pulse voltage to a part of the charged particle beam, wherein a momentum deviation is generated only in a part of the accelerated charged particle beam by applying the pulse voltage to a part of the charged particle beam, and thereby the charged particles of a part of the charged particle beam, the charged particles having a large momentum deviation, are located in a non-stable region and in an extraction region in a horizontal phase space with respect to the traveling direction of the charged particle beam, and wherein a group of the charged particles located in the non-stable region and in the extraction region are extracted into the charged particle beam utility line by using the emission apparatus which selectively and largely deviates the group of the charged particles in the horizontal direction.