Keyword: space-charge
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WEB03 Factors Influencing the Vortex Effect in High-Intensity Cyclotrons cyclotron, bunching, acceleration, simulation 270
 
  • C. Baumgarten
    PSI, Villigen PSI, Switzerland
 
  We discuss factors that have potential influence on the space charge induced vortex motion of particles within high intensity bunches (curling of bunches, Gordon 1969) in isochronous cyclotrons. The influence of the phase slip due to deviations from strict isochronism determines if the bunches of a specific turn are above, below or at "transition", and hence whether stable vortex motion of the bunches is possible at all. Secondly there are possible longitudinal and transverse effects of rf acceleration, the former depending on the bunch phase ("bunching" or "debunching"), the latter depending on the gradient of the accelerating voltage. High accelerating voltages in the first turns call the applicability of adiabatic approximations and analytic methods into question. The influence of the rf acceleration is expected to be significant only at low beam energy, i.e. should have small or even negligible effect beyond the central region of compact machines.  
slides icon Slides WEB03 [1.145 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-WEB03  
About • paper received ※ 16 September 2019       paper accepted ※ 26 September 2019       issue date ※ 20 June 2020  
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WEC01 Conceptual Design of Central Region for High-Temperature Superconducting Skeleton Cyclotron (HTS-SC) cyclotron, injection, extraction, neutron 279
 
  • H.W. Koay, M. Fukuda, H. Kanda, M. Nakao, T. Yorita
    RCNP, Osaka, Japan
 
  A compact high-current accelerator is highly desirable for short and effective Boron Neutron Capture Therapy (BNCT) as well as radioisotopes production in a hospital environment. In accordance with this, a compact high-temperature superconducting skeleton cyclotron (HTS-SC) was proposed. HTS-SC is an air-core K-80 cyclotron with a relatively small extraction radius of 40 cm for a 50 MeV H+ and 40 MeV D+ beam. Owing to its compactness, a relatively high central magnetic field (>2.4 T) remains as a significant challenge for high current injection. This work describes a preliminary study of the injection using a spiral inflector and the central region design of the HTS-SC. Besides, the transverse beam dynamics are also discussed in order to investigate the upper limit of injection current.  
slides icon Slides WEC01 [3.191 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-WEC01  
About • paper received ※ 15 September 2019       paper accepted ※ 25 September 2019       issue date ※ 20 June 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)