Author: Li, Z.Q.
Paper Title Page
MOPAB380 Status and Progress of the RF System for High Energy Photon Source 1165
 
  • P. Zhang, J. Dai, Z.W. Deng, L. Guo, T.M. Huang, D.B. Li, J. Li, Z.Q. Li, H.Y. Lin, Y.L. Luo, Q. Ma, F. Meng, Z.H. Mi, Q.Y. Wang, X.Y. Zhang, F.C. Zhao, H.J. Zheng
    IHEP, Beijing, People’s Republic of China
  
  Funding: This work was supported in part by High Energy Photon Source, a major national science and technology infrastructure in China and in part by the Chinese Academy of Sciences.
High En­ergy Pho­ton Source (HEPS) is a 6 GeV dif­frac­tion-lim­ited syn­chro­tron light source cur­rently under con­struc­tion in Bei­jing. It adopts a dou­ble-fre­quency RF sys­tem with 166.6 MHz as fun­da­men­tal and 499.8 MHz as third har­monic. The fun­da­men­tal cav­ity is mak­ing use of a su­per­con­duct­ing quar­ter-wave β=1 struc­ture and the third har­monic is of su­per­con­duct­ing el­lip­ti­cal sin­gle-cell geom­e­try for the stor­age ring, while nor­mal-con­duct­ing 5-cell cav­i­ties are cho­sen for the booster ring. A total of 900 kW RF power shall be de­liv­ered to the beam by the 166.6 MHz cav­i­ties and the third har­monic cav­i­ties are ac­tive. All cav­i­ties are dri­ven by solid-state power am­pli­fiers and the RF fields are reg­u­lated by dig­i­tal low-level RF con­trol sys­tems. The cav­ity and an­cil­lar­ies, high-power RF sys­tem and low-level RF con­trol sys­tem are in the pro­to­typ­ing phase. This paper pre­sents the cur­rent sta­tus and progress of the RF sys­tem for HEPS. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB380  
About • paper received ※ 09 May 2021       paper accepted ※ 09 June 2021       issue date ※ 24 August 2021  
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MOPAB382 Synchrotron Light Shielding for the 166 MHz Superconducting RF Section at High Energy Photon Source 1169
 
  • X.Y. Zhang, Z.Q. Li, Q. Ma, P. Zhang
    IHEP, Beijing, People’s Republic of China
  
  Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
The High En­ergy Photo Source (HEPS) pro­ject has been under con­struc­tion since 2019, and will be first dif­frac­tion-lim­ited syn­chro­tron light source in China. A 6 GeV elec­tron beam with 200 mA cur­rent will be stored in the main ring. If syn­chro­tron light pro­duced from this en­er­getic elec­tron beam hits the su­per­con­duct­ing cav­ity’s sur­face, it would cause ther­mal break­down of the su­per­con­duc­tiv­ity. In the cur­rent lat­tice de­sign, these lights can­not be fully blocked by the col­li­ma­tor in the up­stream lat­tice cell, there­fore a shield­ing scheme in­side the rf sec­tion is re­quired. This how­ever brings great chal­lenges to the al­ready lim­ited space. The de­sign of the col­li­ma­tor has been fo­cused on ful­fill­ing shield­ing re­quire­ments while op­ti­miz­ing beam im­ped­ance, syn­chro­tron light power den­sity, ther­mal and me­chan­i­cal sta­bil­i­ties. Shield­ing ma­te­ri­als are sub­se­quently cho­sen with ded­i­cated cool­ing to en­sure long-term sta­ble op­er­a­tions. In this paper, a shield­ing scheme in­side the rf sec­tion of the HEPS stor­age ring is pre­sented. The syn­chro­tron light mainly from the up­stream bend­ing mag­net is suc­cess­fully block. The sen­si­tiv­ity to beam po­si­tion move­ment and in­stal­la­tion error is also an­a­lyzed. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB382  
About • paper received ※ 17 May 2021       paper accepted ※ 11 June 2021       issue date ※ 23 August 2021  
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TUPAB340 Design of the Magnetic Shielding for 166 MHz and 500 MHz Superconducting RF Cavities at High Energy Photon Source 2289
 
  • L. Guo, Y. Chen, J. Li, Z.Q. Li, Q. Ma, P. Zhang, X.Y. Zhang, H.J. Zheng
    IHEP, Beijing, People’s Republic of China
  
  Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
Five 166 MHz quar­ter-wave β=1 su­per­con­duct­ing cav­i­ties and two 500 MHz sin­gle-cell el­lip­ti­cal su­per­con­duct­ing cav­i­ties have been de­signed for the stor­age ring of High En­ergy Pho­ton Source (HEPS). It is nec­es­sary to shield mag­netic field for su­per­con­duct­ing cav­i­ties to re­duce the resid­ual sur­face re­sis­tance due to mag­netic flux trap­ping dur­ing cav­ity cool down. The mag­netic shield­ing for both 166 MHz and 500 MHz su­per­con­duct­ing cav­i­ties have been de­signed. The resid­ual mag­netic field in­side the cav­i­ties have been cal­cu­lated by using Opera-3D sim­u­la­tion soft­ware. The ge­o­graphic lo­ca­tion of the cav­ity being in­stalled at the HEPS site and the fringe field of the up­stream mag­net are con­sid­ered. These are re­ported in this paper. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB340  
About • paper received ※ 18 May 2021       paper accepted ※ 17 June 2021       issue date ※ 10 August 2021  
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WEPAB090 Higher Order Mode Damping for 166 MHz and 500 MHz Superconducting RF Cavities at High Energy Photon Source 2798
 
  • H.J. Zheng, Z.Q. Li, F. Meng, N. Wang, H.S. Xu, P. Zhang, X.Y. Zhang
    IHEP, Beijing, People’s Republic of China
  
  Funding: This work was supported in part by High Energy Photon Source, in part by the National Natural Science Foundation of China under Grant No. 11905232.
Su­per­con­duct­ing rf cav­i­ties have been cho­sen for High En­ergy Pho­ton Source, a 6 GeV dif­frac­tion-lim­ited syn­chro­tron light source under con­struc­tion in Bei­jing. The main ac­cel­er­at­ing cav­ity adopted a quar­ter-wave β=1 struc­ture op­er­at­ing at 166 MHz while the third har­monic cav­ity uti­lized the sin­gle-cell el­lip­ti­cal geom­e­try at 500 MHz for the stor­age ring. The high beam cur­rent (200 mA) re­quires a strong damp­ing of higher order modes (HOMs) ex­cited in the su­per­con­duct­ing cav­i­ties. To meet the beam sta­bil­ity re­quire­ments, en­larged beam pipes with a di­am­e­ter of 505 mm for the 166 MHz cav­ity and 300 mm for the 500 MHz cav­ity were cho­sen to allow all HOMs to prop­a­gate along the beam tubes and to be damped by beam-line ab­sorbers. This paper pre­sents the HOM damp­ing scheme and the cav­ity im­ped­ance analy­sis re­sults. In ad­di­tion, power losses due to HOMs were also eval­u­ated for var­i­ous op­er­a­tion modes (high charge and high lu­mi­nos­ity) of the HEPS. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB090  
About • paper received ※ 17 May 2021       paper accepted ※ 22 June 2021       issue date ※ 20 August 2021  
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