Cyclotron and method of adjusting the same having an ion puller electrode with a movable aperture

摘要

A cyclotron comprises a dee, an ion source cone provided with an ion outlet through which ions are emitted, and an ion puller electrode mounted on the dee to pull out ions from the ion source cone through the ion outlet by applying a voltage between the ion source and the ion puller electrode. The ion source cone can be moved from outside the cyclotron without breaking the vacuum of the cyclotron. The ion puller electrode has a sliding aperture member provided with an aperture and capable of being moved relative to the dee. An operating projection of the ion source cone is brought into engagement with the aperture member, and then the ion source cone is moved to move the aperture member to a desired position. Thus, the aperture of the ion puller electrode can be positioned at an appropriate position opposite the ion outlet by moving the ion source cone without requiring any special mechanism for moving the ion puller electrode.