Author: Yuri, Y.
Paper Title Page
Diverse Beam Profile Shapings Through Nonlinear Focusing of Multipole Magnets in a Beam Transport Line  
  • Y. Yuri, T. Yuyama
    QST/Takasaki, Takasaki, Japan
  • M. Fukuda
    RCNP, Osaka, Japan
  It is well-known that the transverse intensity distribution of a charged-particle beam can be made approximately uniform through the nonlinear focusing force using multipole (mainly, octupole) magnets in a beam transport line. This fact indicates that the proper use of multipole magnets enables the diverse beam profile shapings that cannot be achieved by common linear focusing, such as quadrupole magnets. We have, therefore, investigated the feasibility of the beam profile shaping (other than uniform profiles) by means of nonlinear focusing. Recently, we have experimentally demonstrated the formation of an ion beam with a hollow transverse distribution using octupole and sextupole magnets. It has been found that the hollow beam has a steep peak at the radial edge and that its cross-sectional shape varies diversely depending on the order and strength of the applied multipole magnets. In the presentation, the first experimental result of the hollow-beam formation will be reported together with the theoretical analysis of the behavior of a nonlinear-focused beam. Moreover, other unique beam profiles obtained through the nonlinear force of the multipole magnets will also be shown.  
slides icon Slides FRXBA2 [4.111 MB]  
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