Author: Gao, Y.
Paper Title Page
MOPB001 Concepts and Design for Beamline HOM Dampers for eRHIC 39
 
  • P. Kolb, Y. Gao, D. Holmes, K.S. Smith, W. Xu
    BNL, Upton, Long Island, New York, USA
  • Y. Gao
    PKU, Beijing, People's Republic of China
  
  Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
In the design of eRHIC at BNL, HOM power plays a major role for the SRF installation. Depending on the final accelerator design and choice of cavity, up to 100kW of HOM power is estimated to be generated, presenting a big challenge for the HOM damping concept. Due to this high amount of HOM power, all current concepts for eRHIC would use room temperature beam line absorbers equipped with silicone-carbide dielectrics to absorb HOM power. Concepts, designs and simulations for these beam line absorbers will be presented. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB001  
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MOPB052 Dual-ridge Waveguide Load Design for eRHIC 177
 
  • P. Kolb, Y. Gao, C. Pai, R. Porqueddu, K.S. Smith, W. Xu
    BNL, Upton, Long Island, New York, USA
  • Y. Gao
    PKU, Beijing, People's Republic of China
  
  Funding: Work supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
To increase the real estate gradient in the eRHIC electron accelerator waveguide HOM couplers are being considered. These significantly reduce the length of individual cavities and address inter-cavity trapped modes, allowing for an increased number of cavities per cryomodule, which would increase the real estate gradient. The choice of waveguide went to a dual ridge waveguide due to a smaller size compared to rectangular waveguides. The waveguide termination, to convert the RF energy into thermal energy, is a custom designed load based on a silicon carbide dielectric that is already being used in beamline absorbers. Simulations of the RF properties of the load are presented as well as first measurements on a prototype. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB052  
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TUPB002 Novel HOM Damper Design for High Current SRF Cavities 385
 
  • W. Xu, I. Ben-Zvi, M. Blaskiewicz, Y. Gao, D. Holmes, P. Kolb, G.T. McIntyre, R. Porqueddu, K.S. Smith, R. Than, F.J. Willeke, B. P. Xiao, T. Xin, C. Xu, A. Zaltsman
    BNL, Upton, Long Island, New York, USA
  • I. Ben-Zvi
    Stony Brook University, Stony Brook, USA
  • Y. Gao
    PKU, Beijing, People's Republic of China
  
  Funding: This work is supported by LDRD program of Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. DOE.
ERL-Ring eRHIC aims to build a new high current (50 mA), multi-pass (6 passes) ERL to provide 3-18 GeV electron beams to collide with proton beams from existing RHIC. One critical challenge for eRHIC is to damp HOMs. The average HOM power is up to 8 kW per cavity, and it will get worse when the electron beam spectrum overlaps with cavity HOM spectrum. A novel HOM damping scheme by employing ridge waveguides has been worked out at BNL, which is able to well damp both longitudinal and transversal modes. This paper will describe the design of the HOM damping scheme, including RF design, HOM damping results, progress of prototyping. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB002  
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