Author: Fu, Q.
Paper Title Page
TUPVA102 Effect of Beam Losses on Radio Frequency Quadrupole 2325
 
  • Q. Fu, P.P. Gan, S.L. Gao, F.J. Jia, H.P. Li, Y.R. Lu, Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
 
  Funding: the National Basic Research Program of China (2014CB845503)
Most of existing high-current RFQs in the world encounter the degrade of beam transmission or unstable operation, even RF ramping can't go up to nominal design voltage after several years or long time beam commissioning. One of the main reasons is that the irradiation damage to electrode surface, caused by beam losses, influences RF performance of RFQ cavity. This is especially serious for high-current RFQ. By simulation and irradiation experiments, proton irradiation damage to copper target has been studied. The simulation results showed that normally incident proton beams with input energy lower than 1 MeV damage the copper surface in the range of one skin depth at 162.5 MHz, which indicated that almost all the lost beams with small incident angles impact RF performance of RFQ cavity. By the irradiation experiments, the damage within 60 nm depth from surface was proved to have a greater impact on surface finish. The conclusion is that low energy beam losses also need to be kept as low as possible to prolong the life of the RFQ electrodes, especially in high-current RFQ design.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA102  
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TUPVA103 Beam Dynamics Design of the 3MeV RFQ for BISOL Project 2328
 
  • H.P. Li, Q. Fu, P.P. Gan, Y.R. Lu, Z. Wang, K. Zhu
    PKU, Beijing, People's Republic of China
 
  The Beijing isotope separation online (BISOL) facility will be used to study the new physics and technologies at the limit of nuclear stability. The facility can be driven by a reactor or a deuteron accelerator. The driver accelerator for the BISOL facility aims to accelerate a 50 mA D+ beam to 40 MeV. As an injector for the downstream su-perconducting linac, a 4-vane RFQ operating at 162.5 MHz has been designed to accelerate the deuteron beam from 0.05 MeV to 3.0 MeV in CW mode. For the beam dynamics design of this high-intensity RFQ, a matched and equipartitioned design method is adopted in order to control beam loss. After the optimization, the simulated beam transmission efficiency is higher than 99%. The transverse normalized rms emittance growth is approxi-mately 12%. Detailed results of the beam dynamics as well as the error study of the RFQ are presented in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-TUPVA103  
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WEPIK024 HTS-Coated Beam Screen for SPPC Bending Magnets 2974
SUSPSIK007   use link to see paper's listing under its alternate paper code  
 
  • P.P. Gan, Q. Fu, H.P. Li, Y.R. Lu, K. Zhu
    PKU, Beijing, People's Republic of China
  • Y.D. Liu, J.Y. Tang, Q.J. Xu
    IHEP, Beijing, People's Republic of China
 
  For studying new physics beyond the Standard Model, Supper proton-proton Collider (SPPC) with a circumfer-ence of 100 km and a centre mass energy of 100 TeV is proposed and under study in China. Due to the high particle energies and 16 T high magnet field, the synchrotron radiation power emitted from the proton beams reaches 48.5 W/m in the bending magnets, two orders of magnitude higher than that of LHC. A novel beam screen is anticipated to screen cold chamber walls from the massive synchrotron radiation power and transfer the heat load to cryogenic cooling fluid. For drastically reducing resistive wall impedance and saving refrigerator power, we have studied high temperature superconductor (HTS) coated beam screen operating in liquid nitrogen temperature area. Singly from the point of temperature, the feasibility of HTS-coated beam screen is demonstrated by steady-state thermal analysis. Two kinds of potential HTS material are also discussed in this paper.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-WEPIK024  
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