Author: Hae, T.
Paper Title Page
TUP036 Optical Design of AVF Weak-Focusing Accelerator 242
 
  • C. Hori, T. Aoki, T. Seki
    Hitachi Ltd., Ibaraki-ken, Japan
  • T. Hae, H. Hiramoto
    Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken, Japan
 
  A trend in proton beam therapy systems is downsizing their footprints. A larger main magnetic field for the downsizing, however, requires a septum magnet to generate a larger magnetic field for beam extraction. In order to relax the specification of the septum magnet, we consider an azimuthally varying field (AVF) weak-focusing accelerator. The magnetic fields of its hills and valleys can be designed while maintaining the average magnetic fields over the design orbits. Thus, by locating the septum magnet near one of the valleys, the specification is relaxed while keeping the footprint of the accelerator. In this study, we show an optical design of an AVF weak-focusing accelerator with cotangential orbits. The magnetic field in the valleys is smaller than the average magnetic field over the maximum energy orbit by 0.2 T. We evaluate gradient magnetic fields required for beam extraction and find the possibility of variable energy extraction by the static gradient fields.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-TUP036  
About • paper received ※ 13 September 2019       paper accepted ※ 25 September 2019       issue date ※ 20 June 2020  
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TUP037 Compact Cotangential Orbit Accelerator for Particle Therapy 245
 
  • T. Hae, H. Hiramoto
    Hitachi Ltd., Hitachi Research Laboratory, Ibaraki-ken, Japan
  • T. Aoki, C. Hori, Y. Nakashima, F. Noda, T. Seki
    Hitachi Ltd., Ibaraki-ken, Japan
 
  A new type accelerator is being developed for the next generation particle therapy system. This accelerator utilizes a weak focusing DC magnetic field and a frequency modulated RF acceleration. Since a superconducting magnet is applicable to the main magnet, the accelerator can be compact. The accelerator characteristically has cotangential orbits to form an orbit-concentrated region. A beam is extracted from the region by using a new extraction method with the trans-verse RF kicker, peeler and regenerator magnetic fields. In this method an extracted beam energy can be controlled by applied time of the acceleration RF voltage without using an energy selection system (ESS). Intensity and pulse width of the extracted beam can be controlled by a voltage and / or a frequency pattern of the RF kicker.  
poster icon Poster TUP037 [0.740 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-TUP037  
About • paper received ※ 13 September 2019       paper accepted ※ 26 September 2019       issue date ※ 20 June 2020  
Export • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)