SRF2017 - List of Authors (Gu, K.X.)

Paper	Title	Page
MOPB054	Design of Fundamental Power Coupler for High Intensity Heavy-ion Accelerator	183
	B. Bing, T.M. Huang, Q. Ma, F. Meng, W.M. Pan IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	A single-window coaxial coupler at warm has been designed for high intensity heavy-ion accelerator. The coupler is designed to handle 100 kW CW power of 325 MHz and is currently being fabricated. T-bend transition and doorknob have been taken into account. The length of the T-bend short circuit is sensitive to S parameters and contributes to the online adjustment of VSWR in RF conditioning. The doorknob type is adopted to realize the transition from a half-height WR 2300 waveguide to a coaxial line ended with a coupling antenna. This paper describes the RF design, thermal stress and heat load analysis of the coupler as well as multipacting simula-tions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB054
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MOPB069	Design of the High Power Input Coupler for CEPC Main Ring Cavity *	216
	T.M. Huang, Q. Ma, J.Y. Zhai IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The main ring cavities of CEPC project are two-cell el-liptical superconducting cavities operating at 650 MHz in CW mode. Each cavity equips with one high power input coupler and each coupler has to deliver at least 300 kW of CW RF power to the beam. A variable coupling from 10⁵ to 2·10⁶ is required to meet different operation modes. Considering the cavities working with high quali-ty factor up to 2·10¹⁰, the coupler assembled with cavity in class 10 clean room is strongly recommended to protect the cavity from contamination. Also, low cryogenic heat loss is one of the important issues for a large scale CW operation machine. Some of the above requirements should be compromise. Therefore, it's a big challenge to design a high power input coupler fulfilling the above requirements simultaneously. A new coupler that employs 75 Ω coaxial line sections, a planar ceramic disk win-dow, a coaxial to waveguide transition and a coupling adjusting actuator has been designed. In this paper, the RF design, thermal stress analysis and preliminary me-chanical design of the coupler are presented.
	Poster MOPB069 [0.735 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB069
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MOPB070	The Improvement of the Power Coupler for CADS SC Spoke Cavities	220
	T.M. Huang, B. Bing, X. Chen, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, G.W. Wang IHEP, Beijing, People's Republic of China K.X. Gu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	Twenty superconducting spoke cavities mounted in three cryomodules (CM1, CM2 and CM4) were in-stalled in the CADS, a test facility of 10 mA, 25 MeV CW proton linac. Each cavity was equipped with one coaxial type fundamental power coupler (FPC). Fatal window crack was observed during the test cryomod-ule (TCM) commissioning. A series of experiments were subsequently implemented and eventually at-tributed the window crack to the electron bombard-ment from cavity field emission (FE). Improvements covering the coupler cleaning and assembly proce-dure, the structure and position modifications were thus implemented, aiming to reduce the cavity contam-ination and avoid the window damaged by cavity FE electrons. This paper will describe how the coupler window damaged by cavity field emission and the improve-ments for cure. In addition, the performances of FPCs for CM1, CM2 and CM4 were compared.
	Poster MOPB070 [0.613 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB070
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Design of Fundamental Power Coupler for High Intensity Heavy-ion Accelerator

183

B. Bing, T.M. Huang, Q. Ma, F. Meng, W.M. Pan
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

A single-window coaxial coupler at warm has been designed for high intensity heavy-ion accelerator. The coupler is designed to handle 100 kW CW power of 325 MHz and is currently being fabricated. T-bend transition and doorknob have been taken into account. The length of the T-bend short circuit is sensitive to S parameters and contributes to the online adjustment of VSWR in RF conditioning. The doorknob type is adopted to realize the transition from a half-height WR 2300 waveguide to a coaxial line ended with a coupling antenna. This paper describes the RF design, thermal stress and heat load analysis of the coupler as well as multipacting simula-tions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB054

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB069

Design of the High Power Input Coupler for CEPC Main Ring Cavity *

216

T.M. Huang, Q. Ma, J.Y. Zhai
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The main ring cavities of CEPC project are two-cell el-liptical superconducting cavities operating at 650 MHz in CW mode. Each cavity equips with one high power input coupler and each coupler has to deliver at least 300 kW of CW RF power to the beam. A variable coupling from 10⁵ to 2·10⁶ is required to meet different operation modes. Considering the cavities working with high quali-ty factor up to 2·10¹⁰, the coupler assembled with cavity in class 10 clean room is strongly recommended to protect the cavity from contamination. Also, low cryogenic heat loss is one of the important issues for a large scale CW operation machine. Some of the above requirements should be compromise. Therefore, it's a big challenge to design a high power input coupler fulfilling the above requirements simultaneously. A new coupler that employs 75 Ω coaxial line sections, a planar ceramic disk win-dow, a coaxial to waveguide transition and a coupling adjusting actuator has been designed. In this paper, the RF design, thermal stress analysis and preliminary me-chanical design of the coupler are presented.

Poster MOPB069 [0.735 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB069

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB070

The Improvement of the Power Coupler for CADS SC Spoke Cavities

220

T.M. Huang, B. Bing, X. Chen, H.Y. Lin, Q. Ma, F. Meng, W.M. Pan, G.W. Wang
IHEP, Beijing, People's Republic of China
K.X. Gu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

Twenty superconducting spoke cavities mounted in three cryomodules (CM1, CM2 and CM4) were in-stalled in the CADS, a test facility of 10 mA, 25 MeV CW proton linac. Each cavity was equipped with one coaxial type fundamental power coupler (FPC). Fatal window crack was observed during the test cryomod-ule (TCM) commissioning. A series of experiments were subsequently implemented and eventually at-tributed the window crack to the electron bombard-ment from cavity field emission (FE). Improvements covering the coupler cleaning and assembly proce-dure, the structure and position modifications were thus implemented, aiming to reduce the cavity contam-ination and avoid the window damaged by cavity FE electrons. This paper will describe how the coupler window damaged by cavity field emission and the improve-ments for cure. In addition, the performances of FPCs for CM1, CM2 and CM4 were compared.

Poster MOPB070 [0.613 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB070

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)