WEA2WB —  WG-B   (20-Jun-18   11:00—12:30)
Chair: H.W. Zhao, IMP/CAS, Lanzhou, People's Republic of China
Paper Title Page
Beam Loss Mechanisms in Ion Linacs and Development of Beam Collimation System  
  • T. Maruta, Z.Q. He, M. Ikegami, F. Marti, P.N. Ostroumov, J. Wei, Y. Yamazaki, Q. Zhao
    FRIB, East Lansing, USA
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Machine errors and interaction of ion beam with the stripper are known sources of possible beam losses in ion linacs. Our studies show that contaminant ion beams extracted from Electron Cyclotron Resonance ion source and accelerated together with main beam thanks to similar charge-to-mass ratio can produce substantial losses after the stripping due to modified charge-to-mass ratio. The contaminant beams must be well separated and collimated at low energies to avoid losses in the high energy section of the linac. An additional mechanism for beam losses is charge-exchange reactions in the residual gas near the charge selection slits. A set of collimators have been developed to intercept both contaminant ions and main beam halo in the example of Facility for Rare Isotope Beams (FRIB).
slides icon Slides WEA2WB01 [6.205 MB]  
WEA2WB02 Recent Studies of Beam Physics for Ion Linacs -1
  • L. Groening, S. Appel, X. Du, P. Gerhard, M.T. Maier, A. Rubin, P. Scharrer, H. Vormann, C. Xiao
    GSI, Darmstadt, Germany
  • M. Chung
    UNIST, Ulsan, Republic of Korea
  • P. Scharrer
    HIM, Mainz, Germany
  • P. Scharrer
    Mainz University, Mainz, Germany
  The UNIversal Linear ACcelerator (UNILAC) at GSI aims at provision of high brilliant ion beams, as it main purpose will be to serve as injector for the upcoming FAIR accelerator complex. The UNILAC injects into the subsequent synchrotron SIS18 applying horizontal multi-turn injection (MTI). Optimization of this process triggered intense theoretical and experimental studies of dynamics of transversely coupled beams. These activities comprise round-to-flat beam transformation, full 4d transverse beam diagnostics, optimization of the MTI parameters through generic algorithms, and extension of Busch's theorem to accelerated particle beams. Finally, recent advance in modeling time-transition-factors and its impact on improved linac performance will be presented as well as progress in the optimization of ion charge state stripping.  
slides icon Slides WEA2WB02 [4.772 MB]  
HIAF Front End for Transmission and Acceleration of 30 puA 238U35+  
  • Y. Yang
    IMP/CAS, Lanzhou, People's Republic of China
  High Intensity heavy ion Accelerator Facility (HIAF) in China is currently in the state of physics design. The HIAF front end will provide beams of ions with a mass up to uranium at a beam energy of 0.5 MeV/u. The required intensity of uranium beam is of 30 pμA and the charge state is 35+. This paper presents a design of HIAF front end, which includes three ECR ion sources, LEBT, RFQ and MEBT. Beam transmission and dynamics studies have been performed and will be described. These studies include beam extraction simulation from ECR ion source, space charge compensation in LEBT, LEBT beam dynamics with a achromatic system, beam collimation in LEBT, RFQ beam dynamics with pre-bencher. In addition, end-to-end beam simulations have also been carried out to evaluate the front end performance.  
slides icon Slides WEA2WB03 [19.560 MB]