| 摘要 |
The invention comprises a charged particle beam extraction method and apparatus optionally used in conjunction with charged particle beam radiation therapy of cancerous tumors. The system uses a radio-frequency (RF) cavity system to induce oscillation of a charged particle stream. Sufficient amplitude modulation of the charged particle stream causes the charged particle stream to hit a material, such as a foil element of a set of foils. The foil decreases the energy of the charged particle stream, which decreases a radius of curvature of the charged particle stream in the synchrotron sufficiently to allow a physical separation of the reduced energy charged particle stream from the original charged particle stream where thickness of a selected foil is a function of energy of circulating charged particles. The physically separated charged particle stream is then removed from the system by use of an applied field and deflector. |
