| Paper | Title | Page |
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MOPA01 |
Large-Area Uniform Ion Beams Formed by Nonlinear Focusing with Multipole Magnets at the JAEA AVF Cyclotron Facility | |
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| Uniform irradiation with ion beams is a basic accelerator technique for various applications. At the AVF cyclotron facility in Japan Atomic Energy Agency, we have recently realized the formation of ion beams with a large-area (over 100 cm2) uniform intensity distribution by the nonlinear focusing force of multipole magnets for advanced research and future industrial applications. The uniform beam can be formed by the following procedure: First, a beam extracted from the cyclotron, which has a non-Gaussian, complicated profile, is smoothed out by multiple Coulomb scattering into a Gaussian-like one, which is prerequisite for the uniform-beam formation. Then, the tail of the beam is folded into the inside by the nonlinear focusing force of multipole magnets so that the distribution is made uniform on a target. The uniform beam is useful for the suppression of local target heating and efficient low-fluence irradiation in comparison with existing scanning irradiation. In the presentation, the principle of the uniform-beam formation, the beam tuning procedure, the beam profile measurement method, and application examples will be shown. | ||