IPAC2017 - List of Authors (Sha, P.)

Paper	Title	Page
MOPVA080	HOM Simulations and Damping Scheme for CEPC Cavities	1052
	H.J. Zheng, J. Gao, F. Meng, P. Sha, J.Y. Zhai IHEP, Beijing, People's Republic of China
	In this paper, it will be presented that the higher order mode (HOM) analysis of the 650 MHz cavities for the Circular Electron-Positron Collider (CEPC). The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. The conventional coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe, and the propagating modes will be absorbed by the two HOM absorbers at room temperature outside the cryomodule.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA080
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MOPVA078	The Window Replacement and Q Recovery of BEPCII Storage Ring SCC	1046
	T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang IHEP, Beijing, People's Republic of China P. Sha Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail. Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA078
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Paper

Title

Page

HOM Simulations and Damping Scheme for CEPC Cavities

1052

H.J. Zheng, J. Gao, F. Meng, P. Sha, J.Y. Zhai
IHEP, Beijing, People's Republic of China

In this paper, it will be presented that the higher order mode (HOM) analysis of the 650 MHz cavities for the Circular Electron-Positron Collider (CEPC). The higher order modes excited by the intense beam bunches must be damped to avoid additional cryogenic loss and multi-bunch instabilities. To keep the beam stable, the impedance budget and the HOM damping requirement are given. The conventional coaxial HOM coupler, which will be mounted on the beam pipe, is planned to extract the HOM power below the cut-off frequency of the beam pipe, and the propagating modes will be absorbed by the two HOM absorbers at room temperature outside the cryomodule.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA080

Export •

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

MOPVA078

The Window Replacement and Q Recovery of BEPCII Storage Ring SCC

1046

T.M. Huang, J.P. Dai, R. Ge, S.P. Li, Z.Q. Li, H.Y. Lin, Q. Ma, W.M. Pan, Y. Sun, G.W. Wang
IHEP, Beijing, People's Republic of China
P. Sha
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

The storage ring RF system for the upgrade of the Beijing Electron Positron Collider (BEPCII) adopted two 500 MHz superconducting cavities: west for the positron ring (BPR); east for the electron ring (BER). The excessive heating of the west window was observed in Nov.2013, and not cured thoroughly*. After two years operation, the window cracked suddenly on Nov.18th, 2015. The replacement of the window was subsequently implemented in tunnel. However, the quality factor (Q) of the cavity decayed a lot after the window replacement. 90 degrees Celsius N2 gas baking of the outer surface of the cavity was carried out in situ and the Q recovered in a short time. This paper will present the process of the window replacement and the cavity Q recovery in detail.
* Tong-ming Huang et al., Chinese Physics C Vol. 40, No. 6 (2016) 067001

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-MOPVA078

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