SRF2017 - List of Authors (Yang, L.)

Paper	Title	Page
TUPB041	Design of a Triple Spoke Cavity for the HIF Demo Injector	481
	W. Ma, L. Lu, L. Yang IMP/CAS, Lanzhou, People's Republic of China
	Funding: This work was supported by National Nature Science Foundation of China under Grant No. 11475232 and No. 11535016. A 325 MHz triple spoke type superconducting cavity for lead beams with β=0.3 is designed for the heavy ion inertial fusion (HIF) Demo facility. The design and simulations of the triple spoke will be reported in this paper, including the electromagnetic (EM) design and mechanical study using CST microwave studio (MWS) and ANSYS workbench.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB087	Low Temperature and Low Pressure Plasma for the HWR Superconducting Cavity In-situ Cleaning	595
	A.D. Wu, W. Chang, H. Guo, Y. He, C.L. Li, Y.M. Li, P.R. Xiong, L. Yang, W.M. Yue, S.H. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People's Republic of China F. Gou Sichuan University, Chengdu, People's Republic of China
	The glow discharge for low temperature and low pressures plasma were utilized for the half-wave resonator (HWR) superconducting cavity in-situ cleaning. The plasma was on ignition of the Argon/Oxygen mixture atmosphere, which was under the low pressure of 0.5 to 5.0 Pascal. Driven by the RF power with the frequency of the cavity fundamental mode, the plasma showed the typical characteristic of the typical RF glow discharge, which the temperature of the electrons about 1eV that diagnosed by the optical emission spectrum. The experimental parameters for the discharge were optimized to obtain the uniform plasma distribution on the HWR cavity, including the RF power, the atmospheric pressure and the oxygen proportion. At last, the vertical cryogenic test was completed to investigate the impact of active oxygen plasma cleaning on the HWR cavity performance recovery, which contaminated by hydrocarbons. The test proves that the glow plasma clean can relieve the x-ray radiation which caused by the field electron emission effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB087
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPB024	Investigation on Depth Profiling of Niobium Surface Composition and Work Function of SRF Cavities	779
	A.D. Wu, L. Chen, Q.W. Chu, H. Guo, Y. He, Y.M. Li, F. Pan, L. Yang, S.H. Zhang, H.W. Zhao IMP/CAS, Lanzhou, People's Republic of China
	The niobium samples were prepared by different surface treatments that commonly applied for the superconducting RF cavities preparation, as the following of electrochemical polishing, the buffered chemical polishing and high temperature annealing. In order to understand the property of niobium surface, especially the relationship between the composition and the work function value, the X-ray and ultraviolet photoelectron spectra depth profiling has been studied. The intensity photoelectrons signals of O1s, C1s and the Nb3d were identified for composition of the niobium oxide and the hydrocarbon contamination. And the work function of sample surface was measured via the means of the ultraviolet photoelectron spectra band width. To make a depth profiling, the sputtering of Argon ions was used to remove surface material gradually under by control the sputtering times. The results shown that the value of work function strongly depends on the chemical composition.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB024
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Design of a Triple Spoke Cavity for the HIF Demo Injector

481

W. Ma, L. Lu, L. Yang
IMP/CAS, Lanzhou, People's Republic of China

Funding: This work was supported by National Nature Science Foundation of China under Grant No. 11475232 and No. 11535016.
A 325 MHz triple spoke type superconducting cavity for lead beams with β=0.3 is designed for the heavy ion inertial fusion (HIF) Demo facility. The design and simulations of the triple spoke will be reported in this paper, including the electromagnetic (EM) design and mechanical study using CST microwave studio (MWS) and ANSYS workbench.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB041

Export •

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

TUPB087

Low Temperature and Low Pressure Plasma for the HWR Superconducting Cavity In-situ Cleaning

595

A.D. Wu, W. Chang, H. Guo, Y. He, C.L. Li, Y.M. Li, P.R. Xiong, L. Yang, W.M. Yue, S.H. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People's Republic of China
F. Gou
Sichuan University, Chengdu, People's Republic of China

The glow discharge for low temperature and low pressures plasma were utilized for the half-wave resonator (HWR) superconducting cavity in-situ cleaning. The plasma was on ignition of the Argon/Oxygen mixture atmosphere, which was under the low pressure of 0.5 to 5.0 Pascal. Driven by the RF power with the frequency of the cavity fundamental mode, the plasma showed the typical characteristic of the typical RF glow discharge, which the temperature of the electrons about 1eV that diagnosed by the optical emission spectrum. The experimental parameters for the discharge were optimized to obtain the uniform plasma distribution on the HWR cavity, including the RF power, the atmospheric pressure and the oxygen proportion. At last, the vertical cryogenic test was completed to investigate the impact of active oxygen plasma cleaning on the HWR cavity performance recovery, which contaminated by hydrocarbons. The test proves that the glow plasma clean can relieve the x-ray radiation which caused by the field electron emission effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB087

Export •

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

THPB024

Investigation on Depth Profiling of Niobium Surface Composition and Work Function of SRF Cavities

779

A.D. Wu, L. Chen, Q.W. Chu, H. Guo, Y. He, Y.M. Li, F. Pan, L. Yang, S.H. Zhang, H.W. Zhao
IMP/CAS, Lanzhou, People's Republic of China

The niobium samples were prepared by different surface treatments that commonly applied for the superconducting RF cavities preparation, as the following of electrochemical polishing, the buffered chemical polishing and high temperature annealing. In order to understand the property of niobium surface, especially the relationship between the composition and the work function value, the X-ray and ultraviolet photoelectron spectra depth profiling has been studied. The intensity photoelectrons signals of O1s, C1s and the Nb3d were identified for composition of the niobium oxide and the hydrocarbon contamination. And the work function of sample surface was measured via the means of the ultraviolet photoelectron spectra band width. To make a depth profiling, the sputtering of Argon ions was used to remove surface material gradually under by control the sputtering times. The results shown that the value of work function strongly depends on the chemical composition.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-THPB024

Export •

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