Keyword: quadrupole
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MOP008 Mechanical Design of Beam Lines for a 230 MeV SC Cyclotron at CIAE dipole, proton, vacuum, cyclotron 42
 
  • M. Yin, S. An, F.P. Guan, Y.L. Lv, G.F. Pan, F. Wang, F. Wang, S.M. Wei, L.P. Wen, T.J. Zhang, F.Zhu. Zhu
    CIAE, Beijing, People’s Republic of China
 
  Funding: This work was supported in part by the National Natural Science Foundation of China under Grant 11475269 and 11375274.
To develop the proton beam transfer system which used in the field of proton therapy, the mechanical design of proton beam lines based on the CYCIAE-230 has been finished at the China Institute of Atomic Energy (CIAE). The proton beam transfer system includes the beam lines, beam dump, gantry, nozzle, couch, image guidance system, etc. Two beam lines are designed at CIAE this moment. One is for the nozzle system, the other is for the beam dump. The beam lines include four systems: the energy selection system, the beam transportation systems, gantry system, beam dump. The beam lines are very compact in order to match the beam optics and the space limitation. The gantry can be rotated ±180°. There are several key components in beam lines, such as magnets, degrader, beam diagnostics component, vacuum component, etc. The designed mechanical tolerance of the magnets is limited less than 0.1 mm. There are at least four targets on each magnets for collimation and all the components can be adjusted in three dimensions. The magnets are being manufactured now. The mechanical design of proton beam lines based on the CYCIAE-230 will be presented in this paper.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-MOP008  
About • paper received ※ 15 September 2019       paper accepted ※ 26 September 2019       issue date ※ 20 June 2020  
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MOP010 A 50 MeV Proton Beam Line Design proton, cyclotron, target, radiation 45
 
  • S.M. Wei, S. An, L.L. Guan, Y.L. Lv
    CIAE, Beijing, People’s Republic of China
 
  The cyclotron Center at the China Institute of Atomic Energy (CIAE) is now developing a medium-energy proton irradiation device that provides a proton beam with an energy range of 30 MeV to 50 MeV to simulate a space proton radiation environment, which has a significant impact on spacecraft. A beam transport line is designed for irradiation effect study based on the 50 MeV compact cyclotron, which requires continuous adjustment of the beam energy and the beam spot on the target requires high uniformity. The proton beam extracted from the cyclotron is adjusted to the energy required by using the degrader, then the proton beam is bended and focused. In order to obtain uniform large-diameter beam spot on the target, a wobbling magnet is installed on the beam line to uniformly sweep the proton beam on the target and finally obtain the proton beam with energy of 30 MeV - 50 MeV, current of 10 uA and beam spot of 20 cm * 20 cm on the target.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-MOP010  
About • paper received ※ 15 September 2019       paper accepted ※ 26 September 2019       issue date ※ 20 June 2020  
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MOP016 Vertical Focussing with a Field Gradient Spiral Inflector cyclotron, experiment, emittance, optics 58
 
  • A.H. Barnard, J.I. Broodryk, J.L. Conradie, J.G. De Villiers, J. Mira, F. Nemulodi, R.W. Thomae
    iThemba LABS, Somerset West, South Africa
 
  Traditional spiral inflectors suffer from vertical defocussing, leading to beam loss. In this study the electrode shape of an inflector is modified to intentionally produce transverse electric field gradients, which have a significant influence on the optics. This is done by placing the traditionally parallel electrodes at an angle relative to each other in the transverse plane, creating a quadrupole field on the central path. Varying the electrode angle along the path length creates an alternating-gradient effect. The electrode entrance and exit faces are also shaped to create quadrupoles inside the fringe field. By numerical optimisation a design with good vertical focussing is obtained. Experiments show a roughly 100% increase in transmission in cases where the buncher is turned off. However, high losses at extraction are observed with the buncher turned on, due to RF-phase spread introduced by longitudinal defocussing in the inflector. This results in an improvement of only 20% during normal cyclotron operation, and shows that an inflector should ideally focus vertically and longitudinally at the same time. Ongoing work to achieve such combined focussing is described.  
poster icon Poster MOP016 [1.410 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-Cyclotrons2019-MOP016  
About • paper received ※ 13 September 2019       paper accepted ※ 24 September 2019       issue date ※ 20 June 2020  
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