Patent ID: 7332880

Claim:
A particle beam accelerator comprising: an annular vacuum duct having an annular passageway inside for passing a charged particle beam, and including an accelerating unit for accelerating the charged particle beam; a plurality of spiral-shaped-deflecting electromagnets disposed circumferentially along the vacuum duct; and an accelerating core, disposed on the accelerating unit, for accelerating the charged particle beam; wherein the charged particle beam, whose orbit is deflected by the spiral-shaped-deflecting electromagnet, is accelerated by the accelerating unit, the accelerating charged particle beam circulating in the annular vacuum passageway a plurality of times differing in orbit; a gap is formed in the accelerating unit of the vacuum duct; and the gap-constituting face of the vacuum duct is formed to be perpendicular both to the traveling direction of the charged particle beam while circulating in a first orbit, and to the traveling direction of the charged particle beam while circulating in a second orbit.