IPAC2016 - List of Authors (Xu, W.)

Paper	Title	Page
MOPOW054	The 4th Harmonic Cavity for Hefei Light Source-II	837
	C.-F. Wu, S. Dong, G. Huang, D. Jia, K. Jin, C. Li, J.Y. Li, W. Li, J.G. Wang, L. Wang, W. Xu, K. Xuan USTC/NSRL, Hefei, Anhui, People's Republic of China R.A. Bosch UW-Madison/SRC, Madison, Wisconsin, USA G.Y. Kurkin, E. Rotov BINP SB RAS, Novosibirsk, Russia G. Ya Budker Institute of Nuclear Physics, Novosibirsk, Russia
	The 4th harmonic cavity has been firstly used in the storage ring for HLS-II. The paper presents the physics design, developing process and the experimental results for commision. The measurment results show that rf parameters are reasonable. The 4th harmonic cavity efficiently lengthen the bunch and increase the beam life-time. Specially, the beam instablity has been supressed.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW054
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WEPOR002	Orbit Stabilization for the HLS-II Storage Ring	2661
	W. Xu, J.Y. Li, K. Xuan, H.Y. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Hefei Light Source has successfully completed a major upgrade project, which greatly improves the light source performance. As one of the most important criteria, the stability of the beam orbit in the storage ring can greatly influence the overall performance of the light source. In this paper we present our efforts on stabilizing the beam orbit during the commissioning of the HLS-II storage ring. We optimized the performance of the power supplies of the ring corrector magnets. The target beam orbit is obtained by measuring the center of the quadrupole magnets using the beam-based alignment method. We also developed a multi-functional orbit feedback system to keep the beam moving on the golden orbit. With these measures, the beam orbit gets more stable than ten percent of the beam size at the light source points.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR002
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WEPOR003	Voltage Control for the 4-Th Harmonic Cavity in Hls Storage Ring	2664
	K. Xuan, C. Li, J.Y. Li, G. Liu, W. Xu USTC/NSRL, Hefei, Anhui, People's Republic of China
	In order to increase the beam lifetime, a 4th harmonic RF cavity was installed in the HLS-II storage ring. The electrical fields in the principle cavity and high harmonic cavity stretch the beam in the longitudinal direction, and increase the beam volume in phase space, leading to a longer Touschek lifetime. Stable electrical voltage in the high harmonic cavity is essential for steady beam stretching and better beam lifetime. To get a stable high voltage in the high harmonic cavity, we develop a method to maintain steady resonance condition in the cavity using a PID scheme. This paper presents the details of this method. The feedback result is also reported.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR003
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THPMB021	Design of the Magnets of the Far-Infrared FEL Project at NSRL	3269
	T.L. He, H. Xu, W. Xu, S.C. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: National Natural Science Foundation of China (10875118); National Natural Science Foundation of China (11375176) This paper describes the magnetic design of the magnets of the far-infrared free electron laser at NSRL, including dipole magnets and quadrupole magnets with limited installing space. The dipoles are of three different effective lengths and strengths. All the magnets are designed and optimized by using POSSION and OPERA-3D. The end shimming and chamfer are modeled and fully determined by 3D simulation to meet the field uniformity requirement. The design consideration and simulation results are presented in detail.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB021
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THPMB022	Direct and High Resolution Beta-Function Measurements for Storage Ring Lattice Characterization	3272
	W. Li, H. Hao, Y.K. Wu FEL/Duke University, Durham, North Carolina, USA W. Li, W. Xu USTC/NSRL, Hefei, Anhui, People's Republic of China
	Betatron functions are a set of commonly used merits to characterize the lattice performance of a circular accelerator. The betatron functions in many accelerators can be computed using a lattice model trained or calibrated using a set of closed orbit responses, which is exemplified by the widely used LOCO technique. However, for some accelerators, like Duke storage ring with quad-sextupole combined function magnets, LOCO cannot be employed in any straight forward manner. In this case, direct measurements for betatron function are required. One way to determine betatron functions at the location of quadrupoles for a circular accelerator is to use the relationship between the quadrupole strength variations and the corresponding betatron tune change. In this paper, we present a set of carefully developed techniques to accurately measure the betatron functions at the location of quadrupoles, which allow us to achieve extremely high accuracy. Measurement errors will be discussed, and the detailed measurement technique will be present. Finally, we'll report preliminary experimental results of beta function measurements in the Duke storage ring with statistical error on the order of 1%.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB022
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THPMB024	Error Analysis for the Lattice of FELiChEM	3278
	S. Huang, Z.G. He, W. Xu, S.C. Zhang, T. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC).The facility consists of the middle-infrared (MID-FEL) beam line for 2.5-50 um and the Far-infrared (FAR-FEL) beam line for 40-200um. To achieve the design FEL performance of IR-FEL, the beam with 30 mm-mrad emittance, 5 ps rms length and 1nC bunch charge is required. We conduct error analysis in order to evaluate the tolerances of machine parameters and alignments. In this paper, we simulate the orbit corrections and emittance growth under exist of misalignments and strength errors of magnets. The simulation results show that the trajectory errors can be corrected to mm levels in the whole lattice and the emittance increase is acceptable. At the entrance of undulator, the position and angular errors can be corrected very well. So the trajectory can be controlled in the undulator to meet the requirement of FEL.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB024
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THPOR047	Preliminary Concept and Key Technologies of HIEPA Accelerator	3895
	Z.R. Zhou, Q. Luo, L. Wang, W. Xu, B. Zhang USTC/NSRL, Hefei, Anhui, People's Republic of China
	Funding: Supported by National Natural Science Foundation of China (11375178 and 11575181) and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046 High energy physicists proposed a new collider: super tau-charm factory. The name of the project is high intensity electron positron accelerator facility. As high intensity electron positron collider, it runs in an energy range of 2-7 GeV. As an advanced light source, it can also provide high quality synchrotron radiation from VUV to soft X-ray. The facility will be a symmetrical two-ring collider located at Hefei. This paper shows preliminary conception of the storage rings.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR047
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THPOY005	Virtual Accelerator System for Online and Offline Simulations	4094
	S. Ma, C. Li, G. Liu, J.G. Wang, W. Xu, K. Xuan USTC/NSRL, Hefei, Anhui, People's Republic of China
	Synchrotron radiation light sources have been becoming import scientific tools in various research areas. To build a state-of-the-art synchrotron radiation light source, one need to carefully study the linear and nonlinear dynamics of the charged beam in each of the light source components, such as the linac, transfer line, booster synchrotron and storage ring. There are many mature software tools, including MAD, elegant and Accelerator toolkit (AT), can be used to accomplish these tasks. In order to achieve a high performance light source, up-to-date technologies are adopt to build various subsystems. The integration of these subsystems need to be fully tested before the light source is operated. However, there lacks of a good software to perform this work. The virtual light source (VLS), a software based upon EPICS and AT, is developed at the National Synchrotron Radiation Laboratory (NSRL) to fulfill this purpose. This paper presents the details of this software. Some critical applications are also illustrated.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY005
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THPOY028	Operational Status of HLS-II	4155
	J.Y. Li, G. Huang, W. Wei, W. Xu, K. Xuan, Y.L. Yang, Z.R. Zhou USTC/NSRL, Hefei, Anhui, People's Republic of China
	After a major renovation, the Hefei light source (HLS), renamed HLS_II, was brought into operation in the beginning of 2015. The operational result shows that the HLS-II not only provides much brighter synchrotron radiation beam for various users, but also shows much higher reliability than the old light source. This paper first gives an overview of the HLS-II. The overall performance of the light source is then summarized in this paper. Some measured key parameters of the light source, including emittance, orbit stability, beam lifetime and so on, are also presented.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY028
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

The 4th Harmonic Cavity for Hefei Light Source-II

837

C.-F. Wu, S. Dong, G. Huang, D. Jia, K. Jin, C. Li, J.Y. Li, W. Li, J.G. Wang, L. Wang, W. Xu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China
R.A. Bosch
UW-Madison/SRC, Madison, Wisconsin, USA
G.Y. Kurkin, E. Rotov
BINP SB RAS, Novosibirsk, Russia
G. Ya
Budker Institute of Nuclear Physics, Novosibirsk, Russia

The 4th harmonic cavity has been firstly used in the storage ring for HLS-II. The paper presents the physics design, developing process and the experimental results for commision. The measurment results show that rf parameters are reasonable. The 4th harmonic cavity efficiently lengthen the bunch and increase the beam life-time. Specially, the beam instablity has been supressed.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW054

Export •

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

WEPOR002

Orbit Stabilization for the HLS-II Storage Ring

2661

W. Xu, J.Y. Li, K. Xuan, H.Y. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Hefei Light Source has successfully completed a major upgrade project, which greatly improves the light source performance. As one of the most important criteria, the stability of the beam orbit in the storage ring can greatly influence the overall performance of the light source. In this paper we present our efforts on stabilizing the beam orbit during the commissioning of the HLS-II storage ring. We optimized the performance of the power supplies of the ring corrector magnets. The target beam orbit is obtained by measuring the center of the quadrupole magnets using the beam-based alignment method. We also developed a multi-functional orbit feedback system to keep the beam moving on the golden orbit. With these measures, the beam orbit gets more stable than ten percent of the beam size at the light source points.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR002

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WEPOR003

Voltage Control for the 4-Th Harmonic Cavity in Hls Storage Ring

2664

K. Xuan, C. Li, J.Y. Li, G. Liu, W. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

In order to increase the beam lifetime, a 4th harmonic RF cavity was installed in the HLS-II storage ring. The electrical fields in the principle cavity and high harmonic cavity stretch the beam in the longitudinal direction, and increase the beam volume in phase space, leading to a longer Touschek lifetime. Stable electrical voltage in the high harmonic cavity is essential for steady beam stretching and better beam lifetime. To get a stable high voltage in the high harmonic cavity, we develop a method to maintain steady resonance condition in the cavity using a PID scheme. This paper presents the details of this method. The feedback result is also reported.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOR003

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THPMB021

Design of the Magnets of the Far-Infrared FEL Project at NSRL

3269

T.L. He, H. Xu, W. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: National Natural Science Foundation of China (10875118); National Natural Science Foundation of China (11375176)
This paper describes the magnetic design of the magnets of the far-infrared free electron laser at NSRL, including dipole magnets and quadrupole magnets with limited installing space. The dipoles are of three different effective lengths and strengths. All the magnets are designed and optimized by using POSSION and OPERA-3D. The end shimming and chamfer are modeled and fully determined by 3D simulation to meet the field uniformity requirement. The design consideration and simulation results are presented in detail.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB021

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THPMB022

Direct and High Resolution Beta-Function Measurements for Storage Ring Lattice Characterization

3272

W. Li, H. Hao, Y.K. Wu
FEL/Duke University, Durham, North Carolina, USA
W. Li, W. Xu
USTC/NSRL, Hefei, Anhui, People's Republic of China

Betatron functions are a set of commonly used merits to characterize the lattice performance of a circular accelerator. The betatron functions in many accelerators can be computed using a lattice model trained or calibrated using a set of closed orbit responses, which is exemplified by the widely used LOCO technique. However, for some accelerators, like Duke storage ring with quad-sextupole combined function magnets, LOCO cannot be employed in any straight forward manner. In this case, direct measurements for betatron function are required. One way to determine betatron functions at the location of quadrupoles for a circular accelerator is to use the relationship between the quadrupole strength variations and the corresponding betatron tune change. In this paper, we present a set of carefully developed techniques to accurately measure the betatron functions at the location of quadrupoles, which allow us to achieve extremely high accuracy. Measurement errors will be discussed, and the detailed measurement technique will be present. Finally, we'll report preliminary experimental results of beta function measurements in the Duke storage ring with statistical error on the order of 1%.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB022

Export •

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

THPMB024

Error Analysis for the Lattice of FELiChEM

3278

S. Huang, Z.G. He, W. Xu, S.C. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

FELiChEM is a new experimental facility under construction at University of Science and Technology of China (USTC).The facility consists of the middle-infrared (MID-FEL) beam line for 2.5-50 um and the Far-infrared (FAR-FEL) beam line for 40-200um. To achieve the design FEL performance of IR-FEL, the beam with 30 mm-mrad emittance, 5 ps rms length and 1nC bunch charge is required. We conduct error analysis in order to evaluate the tolerances of machine parameters and alignments. In this paper, we simulate the orbit corrections and emittance growth under exist of misalignments and strength errors of magnets. The simulation results show that the trajectory errors can be corrected to mm levels in the whole lattice and the emittance increase is acceptable. At the entrance of undulator, the position and angular errors can be corrected very well. So the trajectory can be controlled in the undulator to meet the requirement of FEL.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB024

Export •

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

THPOR047

Preliminary Concept and Key Technologies of HIEPA Accelerator

3895

Z.R. Zhou, Q. Luo, L. Wang, W. Xu, B. Zhang
USTC/NSRL, Hefei, Anhui, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11375178 and 11575181) and the Fundamental Research Funds for the Central Universities, Grant No WK2310000046
High energy physicists proposed a new collider: super tau-charm factory. The name of the project is high intensity electron positron accelerator facility. As high intensity electron positron collider, it runs in an energy range of 2-7 GeV. As an advanced light source, it can also provide high quality synchrotron radiation from VUV to soft X-ray. The facility will be a symmetrical two-ring collider located at Hefei. This paper shows preliminary conception of the storage rings.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR047

Export •

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

THPOY005

Virtual Accelerator System for Online and Offline Simulations

4094

S. Ma, C. Li, G. Liu, J.G. Wang, W. Xu, K. Xuan
USTC/NSRL, Hefei, Anhui, People's Republic of China

Synchrotron radiation light sources have been becoming import scientific tools in various research areas. To build a state-of-the-art synchrotron radiation light source, one need to carefully study the linear and nonlinear dynamics of the charged beam in each of the light source components, such as the linac, transfer line, booster synchrotron and storage ring. There are many mature software tools, including MAD, elegant and Accelerator toolkit (AT), can be used to accomplish these tasks. In order to achieve a high performance light source, up-to-date technologies are adopt to build various subsystems. The integration of these subsystems need to be fully tested before the light source is operated. However, there lacks of a good software to perform this work. The virtual light source (VLS), a software based upon EPICS and AT, is developed at the National Synchrotron Radiation Laboratory (NSRL) to fulfill this purpose. This paper presents the details of this software. Some critical applications are also illustrated.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY005

Export •

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

THPOY028

Operational Status of HLS-II

4155

J.Y. Li, G. Huang, W. Wei, W. Xu, K. Xuan, Y.L. Yang, Z.R. Zhou
USTC/NSRL, Hefei, Anhui, People's Republic of China

After a major renovation, the Hefei light source (HLS), renamed HLS_II, was brought into operation in the beginning of 2015. The operational result shows that the HLS-II not only provides much brighter synchrotron radiation beam for various users, but also shows much higher reliability than the old light source. This paper first gives an overview of the HLS-II. The overall performance of the light source is then summarized in this paper. Some measured key parameters of the light source, including emittance, orbit stability, beam lifetime and so on, are also presented.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOY028

Export •

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