IPAC2014 - List of Authors (Tang, K.)

Paper	Title	Page
MOPME022	Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna	424
	H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu USTC/NSRL, Hefei, Anhui, People's Republic of China
	A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME022
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TUPRO097	Magnets and Magnetic Field Measurements of Hefei Light Source II	1268
	Q. Luo, N. Chen, G. Feng, N. Hu, K. Tang, Y.L. Yang, J.J. Zheng USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China 11005106, 11105141, and 11375178. The paper introduces magnets and magnetic field measurements of Hefei Light Source II. In the year 2012-2014, NSRL of USTC upgraded the HLS to HLS II. The HLS II, which was built to improve the performance of the light source, in particular to get higher brilliance of synchrotron radiation and increase the number of straight section insertion devices, is now at commissioning stage. Main purpose of this stage is to achieve full energy with high current, fine emittance and enough life time based on adjustment of magnet current, RF voltage and so on. Most of the magnets were replaced during this project. A new magnetic field measurement platform was built and used for the sampling test on new magnets. Test results showed that the discreteness and uniformity of integrated magnetic field of magnets all meet the requirements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO097
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WEPME036	Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio	2341
	J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: National Nature Science Foundation of China under Grant Nos.11075157. In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME036
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THPME140	New Beam Diagnostics and Related Study on HLS Photo-Injector and HLS II	3578
	Q. Luo, H.T. Li, P. Lu, B.G. Sun, K. Tang, J.J. Zheng, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China 11005105, 11005106, 11205156 and 11375178. A team in NSRL is now doing research about small model accelerators and carrying out series of related experiments on HLS photo-injector and HLS II storage ring. Cavity beam multi-parameter monitor system designed for the HLS photocathode RF electron gun consists of a beam position monitor, a beam quadrupole moment monitor and a beam density and bunch length monitor. TM0n0 modes of cavity can be used to work out beam density and bunch length simultaneously. Miniaturization of FEL facilities is now being studied based on results of experiments and theoretical work before. The team also participate in commissioning of HLS II, i.e. measured work points of the new storage ring and did some research on longitudinal bunch-by-bunch feedback system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME140
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THPME141	Design of Beam Intensity Measurement System in Injector for HLS II	3581
	C. Cheng, P. Lu, B.G. Sun, K. Tang, J. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	A new beam intensity measurement (BIM) system has been developed and has been used in the upgrade project of HLS II. After the upgrading is accomplished, electron energy in Injector endpoint will increase from 200MeV to 800MeV to achieve the goal of top-off injector. Meanwhile, macro pulse width changes from 1us to 1ns and peak intensity from 50mA to 1A approximately. So three fast current transformers (FCTs) and two integrating current transformer (ICTs) are installed in Linac and Transport Line to measure single pass beam parameters. In this article, off-line calibration of beam transformer is elaborated. Since the fast pulse signals from beam transformer will be hugely distorted after they transmit from Injector vacuum chamber to the Injector beam diagnostic centre room after hundreds of meters long LMR-400 cable, signal recovery algorithm based on FFT/IFFT is used to re-appear the true original signal and calculate the calibration efficient. In the end, resolution and measurement result of the BIM system is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME141
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THPME142	Design of the Beam Profile Monitors for THz Source Based FEL	3584
	J. Liu, P. Lu, B.G. Sun, K. Tang, J.G. Wang, J. Xu, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	Design of the Beam Profile Monitors for THz Source Based FEL* J. Liu, P. Lu, B. G. Sun#, Y. J. Pei, Y. L. Yang, Z.R. Zhou, J. G. Wang, K. Tang, J. Xu NSRL, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, P. R. China Abstract To meet requirements of high performance THz-FEL, a compact FEL facility was proposed. In order to characterize the beam, some beam profile monitors were designed. There are four flags for beam profiles in Linac，one pop-in monitor for high precision beam profile inside a small-gap undulator, and two screens to measure the beam energy spread and emittance of Linac. On one hand, we need to use software to control the position of these profile monitors, on the other hand, we need screens to display the results. This paper describes how to design and control these monitors, as well as how to measure the beam parameter.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME142
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THPME143	Measuring Energy Spread Using Beam Screen Monitor and Four Strip-Line Electrodes for Hls II Injector*	3587
SUSPSNE076	use link to see paper's listing under its alternate paper code
	K. Tang, J. Liu, P. Lu, Q. Luo, B.G. Sun, H. Xu, J. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to nondestructively measure the beam energy spread with a beam energy of 0.8GeV in the injector at the upgrade project of Hefei Light Source (HLS II) in real time, a beam energy spread monitor (BESM) using beam position monitor (BPM) with four stripline electrodes has been developed. And a screen monitor (SM) near the BESM is used to measure beam energy spread destructively. This paper introduces in brief the beam position measurement system and beam transverse profile measurement system. The relationship between the transverse size at the BESM and at the SM (Flag3) is discussed in detail in this report. The result shows that energy spread measuring result of BESM and SM is 0.19% and 0.18% respectively. So we can draw a conclusion that the BESM is capable of nondestructively measuring the beam energy spread.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME143
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THPME144	Stripline Beam Position Monitor for THz Source Based FEL	3590
	J. Xu, L. Li, J. Liu, P. Lu, Y.J. Pei, B.G. Sun, K. Tang, J.G. Wang, F.F. Wu, H. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou USTC/NSRL, Hefei, Anhui, People's Republic of China
	A 14MeV Linac with both the micro-pulse repetition rate 2856MHz and the macro-pulse width 6us for the THz Source Based FEL was proposed. In order to measure the beam position, a stripline beam position monitor (BPM) was designed, and a commercial BPM electronics Libera Brilliance Single Pass was adopted. As the input carrier frequency of the BPM electrode signal is 2856MHz, but the operating frequency of the Libera Brilliance Single Pass is 500MHz, so a front-end electronics was needed before the electrode signals feed into Libera Brilliance Single Pass. The front-end electronics was designed to make the BPM electrode signals of 2856MHz convert to 500MHz.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME144
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Investigation of the Breakdown and RF Sheath Potential for EAST ICRF Antenna

424

H. Yang, S. Dong, L. Shang, K. Tang, C.-F. Wu
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new ion cyclotron range of frequency (ICRF) antenna was designed with four current straps in Experimental Advanced Superconducting Tokamak (EAST). It is to provide heating, current drive and some physics experiments in EAST. The breakdown and RF sheath potential for the antenna are investigated by a three dimension electromagnetic code in the paper. The plasma is simulated by a slab with high relative permittivity approximating the plasma loading of the antenna. Calculations show that the maximum of electric field is around the end of the coaxial feeds and the strip line and the electric field is strongly dependent on antenna phasing. Especially the maximum of electric field is decreased to 27.5 KV/cm with the (0,π,π,0) phasing between toroidal straps while the value is 32.8 KV/cm with (0,0,π,π) phasing. A challenge in ICRF is the impurity contamination which is related to sheath potential. The topology of the radio frequency (RF) sheath is optimized to reduce the potential for EAST ICRF antenna. The RF potential is mitigated obviously with the broader side limiter by a factor of 2.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-MOPME022

Export •

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

TUPRO097

Magnets and Magnetic Field Measurements of Hefei Light Source II

1268

Q. Luo, N. Chen, G. Feng, N. Hu, K. Tang, Y.L. Yang, J.J. Zheng
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by Natural Science Foundation of China 11005106, 11105141, and 11375178.
The paper introduces magnets and magnetic field measurements of Hefei Light Source II. In the year 2012-2014, NSRL of USTC upgraded the HLS to HLS II. The HLS II, which was built to improve the performance of the light source, in particular to get higher brilliance of synchrotron radiation and increase the number of straight section insertion devices, is now at commissioning stage. Main purpose of this stage is to achieve full energy with high current, fine emittance and enough life time based on adjustment of magnet current, RF voltage and so on. Most of the magnets were replaced during this project. A new magnetic field measurement platform was built and used for the sampling test on new magnets. Test results showed that the discreteness and uniformity of integrated magnetic field of magnets all meet the requirements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-TUPRO097

Export •

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

WEPME036

Simulation of the Trajectory of Electrons in a Magnetron Sputtering System of TiN with CST Particle Studio

2341

J. Wang, L. Fan, Y.Z. Hong, W.L. Liu, X.T. Pei, K. Tang, Y. Wang, W. Wei, Y.H. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Nature Science Foundation of China under Grant Nos.11075157.
In the process of magnetron sputtering deposition, electromagnetic fields have an important influence on the trajectory of particle movement and the properties of the TiN thin film in many cases. Even for simple geometries, the analytical prediction for charged particles trajectories is extremely cumbersome, so numerical simulations are essential to obtain a better understanding of the possible effects and helpful to optimize the design of experimental facility and experimental process. A software of CST PARTICLE STUDIOTM has been used to simulate the effect of magnetic and electric fields on electrons trajectories in the process of film coating. According to the simulation results, the improvement measures of the system design and experimental process have been achieved. The author put forward the improvement measures on film coating process according to the simulation results. The result shows that it is feasible and convenient to use three dimensional tool in the simulation of trajectory of electrons in a magnetron sputtering system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-WEPME036

Export •

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

THPME140

New Beam Diagnostics and Related Study on HLS Photo-Injector and HLS II

3578

Q. Luo, H.T. Li, P. Lu, B.G. Sun, K. Tang, J.J. Zheng, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Work supported by Natural Science Foundation of China 11005105, 11005106, 11205156 and 11375178.
A team in NSRL is now doing research about small model accelerators and carrying out series of related experiments on HLS photo-injector and HLS II storage ring. Cavity beam multi-parameter monitor system designed for the HLS photocathode RF electron gun consists of a beam position monitor, a beam quadrupole moment monitor and a beam density and bunch length monitor. TM0n0 modes of cavity can be used to work out beam density and bunch length simultaneously. Miniaturization of FEL facilities is now being studied based on results of experiments and theoretical work before. The team also participate in commissioning of HLS II, i.e. measured work points of the new storage ring and did some research on longitudinal bunch-by-bunch feedback system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME140

Export •

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

THPME141

Design of Beam Intensity Measurement System in Injector for HLS II

3581

C. Cheng, P. Lu, B.G. Sun, K. Tang, J. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

A new beam intensity measurement (BIM) system has been developed and has been used in the upgrade project of HLS II. After the upgrading is accomplished, electron energy in Injector endpoint will increase from 200MeV to 800MeV to achieve the goal of top-off injector. Meanwhile, macro pulse width changes from 1us to 1ns and peak intensity from 50mA to 1A approximately. So three fast current transformers (FCTs) and two integrating current transformer (ICTs) are installed in Linac and Transport Line to measure single pass beam parameters. In this article, off-line calibration of beam transformer is elaborated. Since the fast pulse signals from beam transformer will be hugely distorted after they transmit from Injector vacuum chamber to the Injector beam diagnostic centre room after hundreds of meters long LMR-400 cable, signal recovery algorithm based on FFT/IFFT is used to re-appear the true original signal and calculate the calibration efficient. In the end, resolution and measurement result of the BIM system is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME141

Export •

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

THPME142

Design of the Beam Profile Monitors for THz Source Based FEL

3584

J. Liu, P. Lu, B.G. Sun, K. Tang, J.G. Wang, J. Xu, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

Design of the Beam Profile Monitors for THz Source Based FEL* J. Liu, P. Lu, B. G. Sun#, Y. J. Pei, Y. L. Yang, Z.R. Zhou, J. G. Wang, K. Tang, J. Xu NSRL, School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, P. R. China Abstract To meet requirements of high performance THz-FEL, a compact FEL facility was proposed. In order to characterize the beam, some beam profile monitors were designed. There are four flags for beam profiles in Linac，one pop-in monitor for high precision beam profile inside a small-gap undulator, and two screens to measure the beam energy spread and emittance of Linac. On one hand, we need to use software to control the position of these profile monitors, on the other hand, we need screens to display the results. This paper describes how to design and control these monitors, as well as how to measure the beam parameter.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME142

Export •

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

THPME143

Measuring Energy Spread Using Beam Screen Monitor and Four Strip-Line Electrodes for Hls II Injector*

3587

SUSPSNE076

use link to see paper's listing under its alternate paper code

K. Tang, J. Liu, P. Lu, Q. Luo, B.G. Sun, H. Xu, J. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to nondestructively measure the beam energy spread with a beam energy of 0.8GeV in the injector at the upgrade project of Hefei Light Source (HLS II) in real time, a beam energy spread monitor (BESM) using beam position monitor (BPM) with four stripline electrodes has been developed. And a screen monitor (SM) near the BESM is used to measure beam energy spread destructively. This paper introduces in brief the beam position measurement system and beam transverse profile measurement system. The relationship between the transverse size at the BESM and at the SM (Flag3) is discussed in detail in this report. The result shows that energy spread measuring result of BESM and SM is 0.19% and 0.18% respectively. So we can draw a conclusion that the BESM is capable of nondestructively measuring the beam energy spread.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME143

Export •

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

THPME144

Stripline Beam Position Monitor for THz Source Based FEL

3590

J. Xu, L. Li, J. Liu, P. Lu, Y.J. Pei, B.G. Sun, K. Tang, J.G. Wang, F.F. Wu, H. Xu, Y.L. Yang, Z.R. Zhou, J.Y. Zou
USTC/NSRL, Hefei, Anhui, People's Republic of China

A 14MeV Linac with both the micro-pulse repetition rate 2856MHz and the macro-pulse width 6us for the THz Source Based FEL was proposed. In order to measure the beam position, a stripline beam position monitor (BPM) was designed, and a commercial BPM electronics Libera Brilliance Single Pass was adopted. As the input carrier frequency of the BPM electrode signal is 2856MHz, but the operating frequency of the Libera Brilliance Single Pass is 500MHz, so a front-end electronics was needed before the electrode signals feed into Libera Brilliance Single Pass. The front-end electronics was designed to make the BPM electrode signals of 2856MHz convert to 500MHz.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2014-THPME144

Export •

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