SRF2017 - List of Authors (He, Y.)

Paper	Title	Page
MOXA01	Successful Beam Commissioning of Chinese ADS Injector-II
	Y. He IMP/CAS, Lanzhou, People's Republic of China
	Since 2011, the key technologies for superconducting proton linac were developed in CAS for Accelerator Driven System. The sc linac of 10 MeV base on spoke resonators (Spoke), named injector I, was built in IHEP. The other one base on half-wave resonators (HWR), named injector II, was built in IMP. Both injectors were commissioned successfully with more than 1 mA CW beam. The front-end demo linac for ADS is based on injector II with succeeding by one taper-type HWR cryomodule and one Spoke cryomodule. It can accelerate 10 mA beam to energy of 25 MeV. The last two cryomodules of the demo linac started tunnel installation since January and cooling down in May. The first beam was on May 27th, and 12 mA (@ 26 MeV) pulse beam and 170 us (@ 25 MeV) CW beam were demonstrated on July 6th. The background of the project will be introduced. The lessons and experiences of CW SRF and mA beam commissioning on injector II and the 25 MeV demo linac will be presented.
	Slides MOXA01 [16.512 MB]
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB007	Design of the Superconducting Quarter Wave Resonators for HIAF	59
	C. Zhang, L. Chen, Q.W. Chu, H. Guo, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, L. Li, Y.M. Li, F. Pan, T. Tan, R.X. Wang, A.D. Wu, Q.J. Wu, P.R. Xiong, W.M. Yue, S.H. Zhang, S.X. Zhang IMP/CAS, Lanzhou, People's Republic of China
	A heavy ion accelerator facility (HIAF) is under development in the Institute of Modern Physics. For the low energy superconducting accelerating section, two types of quarter wave resonators with frequency of 81.25 MHz and β of 0.05 and 0.10 have been proposed. The electro-magnetic design has been optimized in order to reach the high accelerating voltage, and the optimization also included the drift tube face tilting to compensate for the beam steering caused by the asymmetry in the quarter wave resonator geometry.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB007
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB074	Analysis of Higher Order Modes of the Superconducting Cavities for the China-ADS Injector-II in IMP	231
	C. Zhang, L. Chen, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, Y.M. Li, F. Pan, R.X. Wang, A.D. Wu, Q.J. Wu, W.M. Yue, S.H. Zhang, S.X. Zhang IMP/CAS, Lanzhou, People's Republic of China
	Funding: funded by Natural Science Foundation of China， No.11505253 The influence of the higher order modes on the beam dynamics and the cryogenic losses has been studied for the superconducting section of the CIADS project in this paper. In addition, the necessity of HOM dampers in the Superconducting (SC) cavities is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB074
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB039	Electropolishing of Niobium from Deep Eutectic Solvents Based on Choline Chloride	475
	Q.W. Chu, H. Guo, Y. He, L. Li, P.R. Xiong, Z.M. You, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	Niobium (Nb) was successfully electropolished from a green ionic liquid, choline chloride/urea deep eutectic solvent (DES). This paper was to investigate the influence of various electropolishing parameters, including electropolishing time, temperature and voltage, on the electropolishing rate, surface roughness, glossiness and microstructure of Nb. The result showed that the electropolishing parameters had a significant impact on the performance of Nb. Based on surface analysis by scanning electron microscope (SEM) and atomic force microscope (AFM), smooth Nb can be achieved under properly controlled conditions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB039
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB040	Design and Optimization of Medium and High Beta Superconducting Elliptical Cavities for the CW Linac in CIADS	478
	Y.L. Huang, L. Chen, Y. He, Y.M. Li, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	Superconducting technology is adopted in the main accelerating section of the CW Linac in China Initiative Accelerator Driven System (CIADS) to accelerate the 10 mA proton beam from 2.1 MeV up to 1.5 GeV. The high energy section of the superconducting linac is composed of two families of SC elliptical cavities with optimum beta 0.62 and 0.82 for the acceleration of proton beam from 178 MeV to 1.5 GeV. In this paper, the design and optimization of the 650 MHz medium and high beta elliptical cavities are discussed, including the RF design, multipacting analysis, high order modes (HOMs) analysis, generator RF power calculation, and the mechanical design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB040
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB086	Study on Local Chemical Treatment for Recovery From Surface Oxidation by HPR Process on SRF Cavities	592
	H. Guo, Y. He, Y.M. Li, T. Tan, A.D. Wu, P.R. Xiong, Z.M. You, W.M. Yue, S.H. Zhang IMP/CAS, Lanzhou, People's Republic of China
	High pressure rinsing (HPR) with ultra-pure water (UPW) is the last step which is commonly used for SRF cavities cleaning. The serious surface damage will be caused due to the failure of the distance control between the jet and cavity surface or the breakdown of the jet rotation. The surface of taper HWR cavities which are used for CIADS project was damaged in HPR process. Two methods were used for surface recovery and the result will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB086
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)

TUPB112	First Test of Electropolishing System at IMPCAS	660
	L. Li, Q.W. Chu, H. Guo, Y. He, P.R. Xiong, Z.Q. Yang, Z.M. You, B. Zhang, S.H. Zhang, X. Zhu IMP/CAS, Lanzhou, People's Republic of China
	The first SRF cavity electropolishing system of China has been built by IMPCAS. We used two type of cathodes in different process parameters to test the typical Voltage-Current Density curves of 1.3GHz one-cell SRF cavity.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB112
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

MOXA01

Successful Beam Commissioning of Chinese ADS Injector-II

Y. He
IMP/CAS, Lanzhou, People's Republic of China

Since 2011, the key technologies for superconducting proton linac were developed in CAS for Accelerator Driven System. The sc linac of 10 MeV base on spoke resonators (Spoke), named injector I, was built in IHEP. The other one base on half-wave resonators (HWR), named injector II, was built in IMP. Both injectors were commissioned successfully with more than 1 mA CW beam. The front-end demo linac for ADS is based on injector II with succeeding by one taper-type HWR cryomodule and one Spoke cryomodule. It can accelerate 10 mA beam to energy of 25 MeV. The last two cryomodules of the demo linac started tunnel installation since January and cooling down in May. The first beam was on May 27th, and 12 mA (@ 26 MeV) pulse beam and 170 us (@ 25 MeV) CW beam were demonstrated on July 6th. The background of the project will be introduced. The lessons and experiences of CW SRF and mA beam commissioning on injector II and the 25 MeV demo linac will be presented.

Slides MOXA01 [16.512 MB]

Export •

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

MOPB007

Design of the Superconducting Quarter Wave Resonators for HIAF

59

C. Zhang, L. Chen, Q.W. Chu, H. Guo, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, L. Li, Y.M. Li, F. Pan, T. Tan, R.X. Wang, A.D. Wu, Q.J. Wu, P.R. Xiong, W.M. Yue, S.H. Zhang, S.X. Zhang
IMP/CAS, Lanzhou, People's Republic of China

A heavy ion accelerator facility (HIAF) is under development in the Institute of Modern Physics. For the low energy superconducting accelerating section, two types of quarter wave resonators with frequency of 81.25 MHz and β of 0.05 and 0.10 have been proposed. The electro-magnetic design has been optimized in order to reach the high accelerating voltage, and the optimization also included the drift tube face tilting to compensate for the beam steering caused by the asymmetry in the quarter wave resonator geometry.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB007

Export •

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

MOPB074

Analysis of Higher Order Modes of the Superconducting Cavities for the China-ADS Injector-II in IMP

231

C. Zhang, L. Chen, Y. He, S.C. Huang, Y.L. Huang, T.C. Jiang, Y.M. Li, F. Pan, R.X. Wang, A.D. Wu, Q.J. Wu, W.M. Yue, S.H. Zhang, S.X. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Funding: funded by Natural Science Foundation of China， No.11505253
The influence of the higher order modes on the beam dynamics and the cryogenic losses has been studied for the superconducting section of the CIADS project in this paper. In addition, the necessity of HOM dampers in the Superconducting (SC) cavities is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-MOPB074

Export •

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

TUPB039

Electropolishing of Niobium from Deep Eutectic Solvents Based on Choline Chloride

475

Q.W. Chu, H. Guo, Y. He, L. Li, P.R. Xiong, Z.M. You, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Niobium (Nb) was successfully electropolished from a green ionic liquid, choline chloride/urea deep eutectic solvent (DES). This paper was to investigate the influence of various electropolishing parameters, including electropolishing time, temperature and voltage, on the electropolishing rate, surface roughness, glossiness and microstructure of Nb. The result showed that the electropolishing parameters had a significant impact on the performance of Nb. Based on surface analysis by scanning electron microscope (SEM) and atomic force microscope (AFM), smooth Nb can be achieved under properly controlled conditions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB039

Export •

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

TUPB040

Design and Optimization of Medium and High Beta Superconducting Elliptical Cavities for the CW Linac in CIADS

478

Y.L. Huang, L. Chen, Y. He, Y.M. Li, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

Superconducting technology is adopted in the main accelerating section of the CW Linac in China Initiative Accelerator Driven System (CIADS) to accelerate the 10 mA proton beam from 2.1 MeV up to 1.5 GeV. The high energy section of the superconducting linac is composed of two families of SC elliptical cavities with optimum beta 0.62 and 0.82 for the acceleration of proton beam from 178 MeV to 1.5 GeV. In this paper, the design and optimization of the 650 MHz medium and high beta elliptical cavities are discussed, including the RF design, multipacting analysis, high order modes (HOMs) analysis, generator RF power calculation, and the mechanical design.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB040

Export •

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

TUPB086

Study on Local Chemical Treatment for Recovery From Surface Oxidation by HPR Process on SRF Cavities

592

H. Guo, Y. He, Y.M. Li, T. Tan, A.D. Wu, P.R. Xiong, Z.M. You, W.M. Yue, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

High pressure rinsing (HPR) with ultra-pure water (UPW) is the last step which is commonly used for SRF cavities cleaning. The serious surface damage will be caused due to the failure of the distance control between the jet and cavity surface or the breakdown of the jet rotation. The surface of taper HWR cavities which are used for CIADS project was damaged in HPR process. Two methods were used for surface recovery and the result will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB086

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)

TUPB112

First Test of Electropolishing System at IMPCAS

660

L. Li, Q.W. Chu, H. Guo, Y. He, P.R. Xiong, Z.Q. Yang, Z.M. You, B. Zhang, S.H. Zhang, X. Zhu
IMP/CAS, Lanzhou, People's Republic of China

The first SRF cavity electropolishing system of China has been built by IMPCAS. We used two type of cathodes in different process parameters to test the typical Voltage-Current Density curves of 1.3GHz one-cell SRF cavity.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-SRF2017-TUPB112

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)