IPAC2018 - List of Authors (Duan, Z.)

Paper	Title	Page
MOPMF021	Ground Motion Measurement and Analysis for HEPS	125
	F. Yan, Z. Duan, D. Ji, Y. Jiao, Z.Z. Wang, Y. Wei, G. Xu IHEP, Beijing, People's Republic of China
	HEPS have very challenging beam stability require-ments. Special cares are mandatory in developing site vibration specifications, stable building design concepts, and passive and active ways to minimize effects on the stability of the photon beam and critical accelerator and beamline components caused by ambient ground motion sources. However, among all these work, reasonable as-sessment of the vibration induced beam instability has to be the first step. This paper will focuses on the measure-ment results of the ground motion on HEPS site, the es-tablishment of reasonable beam dynamic models, the influences of ground motion to the beam of main ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF021
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TUPMF046	The Injection and Extraction Design of the Booster for the HEPS Project	1356
	Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu IHEP, Beijing, People's Republic of China
	The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF046
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TUPMF048	On-Axis Beam Accumulation Based on a Triple-Frequency RF System for Diffraction-Limited Storage Rings	1359
SUSPF029	use link to see paper's listing under its alternate paper code
	S.C. Jiang, Z. Duan, G. Xu IHEP, Beijing, People's Republic of China
	Since the multi-bend achromats have been applied to lattice design in the future light source to achieve ultralow emittance, strong sextupoles and concomitant nonlinearities restrict its performance to a certain extent. The empirical understanding is the exclusion of conventional off-axis injection scheme on these light sources. In this paper, we will present a new on-axis beam accumulation scheme, which is based on the triple-frequency RF system. By means of delicate superposition of RF voltage with fundamental and two other harmonic frequencies, a commodious and steady main bucket is able to be formed. The electron bunch from the injector will be kicked into the main bucket on-axis with a reasonable time offset to the circular bunch, and this process may make the minimal disturbance to the experiment users while operating on the top-up mode. The application of this scheme to the High Energy Photon Source (HEPS) will be discussed in the paper, corresponding simulation results are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF048
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TUPMF052	Progress of Lattice Design and Physics Studies on the High Energy Photon Source	1375
	G. Xu, X. Cui, Z. Duan, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is an ultralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physical design and studies on HEPS over the past one year, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, beam lifetime, etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF052
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TUPMF055	Phase Matching Application in Hard X-Ray Region of HEPS	1386
	X.Y. Li, Z. Duan, Y. Jiao, S.K. Tian IHEP, Beijing, People's Republic of China
	For the 6 meters long straight-section of HEPS, a double collinear double-cryogenic permanent magnet undulator(CPMU) structure is designed for high energy photon users to achieve higher brightness. Angular profiles of radiation produced by the double undulator configuration has been derived analytically. The efficiency of phase shifter on improving the brightness of double-CPMU is therefore evaluated with the beam energy spread is taken into account.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF055
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TUPMF058	Conceptual Design of HEPS Injector	1394
	J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou IHEP, Beijing, People's Republic of China
	Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF058
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TUPMF062	Status of HEPS Booster Lattice Design and Physics Studies	1407
	Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF062
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WEPMF032	Experimental Studies on Secondary Electron Emission Characteristics for Chamber Materials of Accelerators	2425
	Y. Jiao, Z. Duan, W.B. Liu, Y.D. Liu IHEP, Beijing, People's Republic of China Liu. S. Liu Institute of High Energy Physics (IHEP), People's Republic of China P.C. Wang DNSC, Dongguan, People's Republic of China
	Funding: National Natural Science Foundation of China (11275221) and Key Laboratory Foundation of Particle Acceleration Physics &Technology (Y5294106TD) Secondary electron emission (SEE) of surface is origin of multipacting effect which could seriously deteriorate beam quality and even perturb the normal operation of particle accelerators. Experimental measurements on secondary electron yield (SEY) on different materials and coating have been developed in many accelerator laboratory. In fact, the SEY is just one parameter of secondary electron emission characteristics which include spatial and energy distribution of emitted electrons. A novel experimental apparatus was set up in China Spallation Neutron Source (CSNS) and innovative measurement methods were applied to obtain the whole characteristics of SEE. With some traditional accelerator chamber materials such as Cu, Al, TiN, SEY dependence on primary electron energy and beam injection angle, spatial and energy distribution of emitted secondary electrons were achieved with this measurement apparatus. This contribution also tries to give all the experimental results a reasonable theoretical analysis.
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WEPML069	Fast Kicker and Pulser R&D for the HEPS on-Axis Injection System	2846
	H. Shi, J. Chen, Z. Duan, L. Huo, P. Liu, X.L. Shi, G. Wang, L. Wang, N. Wang IHEP, Beijing, People's Republic of China
	The HEPS plans to adopt on-axis injection scheme because the dynamic aperture of machine is not large enough for off-axis injection for its baseline 7BA lattice design. A sets of super fast kicker and pulser of ±15kV amplitude, 15ns pulse bottom width are needed for bunch spacing of 10ns to minimize perturbation on adjacent bunches. To achieve these requirement, a multifaceted R&D program including the strip-line kicker and HV pulser, was initiated last 2 years. So far, the prototype development of a 750mm long strip-line kicker and a DSRD pulser was completed and the preliminary test results show they can meet the baseline requirement of the HEPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML069
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THPAF014	Studies of the Single-Bunch Instabilities in the Booster of HEPS	2971
	H.S. Xu, Z. Duan, J.L. Li, Y.M. Peng, S.K. Tian, N. Wang IHEP, Beijing, People's Republic of China
	High Energy Photon Source (HEPS), which is proposed in China, is an ultra-low emittance storage ring based synchrotron light source. Because of the requirement of the relatively high single-bunch charge, the booster may suffer from the single-bunch instabilities. A preliminary impedance model has been developed for the studies of collective instabilities in the booster. Based on this impedance model, the longitudinal and transverse single-bunch instabilities have been studied.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF014
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THPAK014	Analytical Estimation of the Beam Ion Instability in HEPS	3231
	N. Wang, Z. Duan, S.K. Tian, H.S. Xu IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a new designed photon source at beam energy of 6 GeV, with natural beam emittance less than 100pm. Due to the small transverse beam size, beam ion instability is one of the potential issues for HEPS. The growth time of the instability is estimated analytically for different operation scenarios. The results show considerably good agreement with the wake strong simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK014
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THPAK015	Impedance and Heat Load Analysis of the Stripline Kicker in HEPS	3234
	N. Wang, J. Chen, Z. Duan, H. Shi, S.K. Tian, L. Wang, H.S. Xu IHEP, Beijing, People's Republic of China
	In the High Energy Photon Source (HEPS), strip-line kickers are adopted for beam injection and extraction. Beam coupling impedance contribution from the strip-line kicker is calculated. Detailed studies on the heat load dissipation have been performed. The peak electric field on the blade and the induced voltage on the feedthroughs due to the beam passage are also calculated.
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THPAK016	Measurement and Analysis of Synchrotron Tune Variation with Beam Current in BEPCII	3237
	N. Wang, Z. Duan, G. Xu, H.S. Xu, C.H. Yu, Y. Zhang IHEP, Beijing, People's Republic of China
	Coherent synchrotron frequency shift is observed during machine studies in BEPCII (Beijing Electron Positron Collider Upgrade). The results show that the synchrotron frequency varies parabolically with the increase of the beam current. This phenomenon is supposed to be induced by the interaction of the beam with the fundamental mode of the accelerating cavity. In order to explain this phenomenon, a simple physical model is developed from the couple bunch instability theory. The analytical estimations based on the physical model show good agreement with the measurements.
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THPMF052	The Swap-Out Injection Scheme for the High Energy Photon Source	4178
	Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu IHEP, Beijing, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China (No.11605212). The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.
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THPMF053	Study of the Dynamic Aperture Reduction Due to Error Effects for the High Energy Photon Source	4182
	Z. Duan, D. Ji, Y. Jiao IHEP, Beijing, People's Republic of China
	Funding: Work supported by Natural Science Foundation of China(No.11605212). The 6 GeV High Energy Photon Source (HEPS) employs a lattice of 48 hybrid 7BA cells, aims to achieve a natural emittance between 30 to 60 pm, within a circumference of about 1.3 km. In the performance evaluation of optimized lattices, we found that the dynamic aperture of the bare lat- tice were su cient for on-axis swap-out injection, but a large reduction in the dynamic aperture was observed in the simu- lation when including lattice imperfections and even after dedicated lattice corrections. In this paper, we identi ed the feed-down e ects of sextupoles as the major source of DA reduction, and proposed to use dedicated sextupole movers to e ciently reduce the orbit o sets in sextupoles, to par- tially recover the dynamic aperture, sextupole mover-based optics correction schemes were also discussed.
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THPMF054	Beam Performance Simulation with Error Effects and Correction on HEPS Design	4186
	D. Ji, X. Cui, Z. Duan, Y. Jiao, Y. Wei, Y.L. Zhao IHEP, Beijing, People's Republic of China
	The High Energy Photon Source (HEPS) is a 6-GeV, ul-tralow-emittance kilometre-scale storage ring light source to be built in China. In this paper, the progress of the error and correction effect study on HEPS over the past one year will be presented, including error requirement and correction progress update. And beam performance eval-uation with static error and correction on orbit, optics, emittance and dynamic aperture will be presented.
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Paper

Title

Page

Ground Motion Measurement and Analysis for HEPS

125

F. Yan, Z. Duan, D. Ji, Y. Jiao, Z.Z. Wang, Y. Wei, G. Xu
IHEP, Beijing, People's Republic of China

HEPS have very challenging beam stability require-ments. Special cares are mandatory in developing site vibration specifications, stable building design concepts, and passive and active ways to minimize effects on the stability of the photon beam and critical accelerator and beamline components caused by ambient ground motion sources. However, among all these work, reasonable as-sessment of the vibration induced beam instability has to be the first step. This paper will focuses on the measure-ment results of the ground motion on HEPS site, the es-tablishment of reasonable beam dynamic models, the influences of ground motion to the beam of main ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-MOPMF021

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TUPMF046

The Injection and Extraction Design of the Booster for the HEPS Project

1356

Y.Y. Guo, J. Chen, Z. Duan, Y. Jiao, Y.M. Peng, G. Xu
IHEP, Beijing, People's Republic of China

The HEPS booster is a 1Hz electron synchrotron. It accelerates electron bunches from 500 MeV to final energy of 6 GeV. The vertical scheme was chosen for the injection and extraction system of the booster. What's more, an injection system from storage ring is required. The layout of the injection and extraction system were introduced in this paper. The parameter optimization and other considerations are presented in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF046

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TUPMF048

On-Axis Beam Accumulation Based on a Triple-Frequency RF System for Diffraction-Limited Storage Rings

1359

SUSPF029

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

S.C. Jiang, Z. Duan, G. Xu
IHEP, Beijing, People's Republic of China

Since the multi-bend achromats have been applied to lattice design in the future light source to achieve ultralow emittance, strong sextupoles and concomitant nonlinearities restrict its performance to a certain extent. The empirical understanding is the exclusion of conventional off-axis injection scheme on these light sources. In this paper, we will present a new on-axis beam accumulation scheme, which is based on the triple-frequency RF system. By means of delicate superposition of RF voltage with fundamental and two other harmonic frequencies, a commodious and steady main bucket is able to be formed. The electron bunch from the injector will be kicked into the main bucket on-axis with a reasonable time offset to the circular bunch, and this process may make the minimal disturbance to the experiment users while operating on the top-up mode. The application of this scheme to the High Energy Photon Source (HEPS) will be discussed in the paper, corresponding simulation results are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF048

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TUPMF052

Progress of Lattice Design and Physics Studies on the High Energy Photon Source

1375

G. Xu, X. Cui, Z. Duan, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, X.Y. Li, C. Meng, Y.M. Peng, Q. Qin, S.K. Tian, J.Q. Wang, N. Wang, Y. Wei, H.S. Xu, F. Yan, C.H. Yu, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is an ultralow-emittance, kilometer-scale storage ring light source to be built in China. In this paper we will introduce the progress of the physical design and studies on HEPS over the past one year, covering issues of storage lattice design and optimization, booster design, injection design, collective effects, error study, insertion device effects, beam lifetime, etc.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF052

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TUPMF055

Phase Matching Application in Hard X-Ray Region of HEPS

1386

X.Y. Li, Z. Duan, Y. Jiao, S.K. Tian
IHEP, Beijing, People's Republic of China

For the 6 meters long straight-section of HEPS, a double collinear double-cryogenic permanent magnet undulator(CPMU) structure is designed for high energy photon users to achieve higher brightness. Angular profiles of radiation produced by the double undulator configuration has been derived analytically. The efficiency of phase shifter on improving the brightness of double-CPMU is therefore evaluated with the beam energy spread is taken into account.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF055

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TUPMF058

Conceptual Design of HEPS Injector

1394

J.L. Li, H. Dong, Z. Duan, Y.Y. Guo, D.Y. He, Y. Jiao, W. Kang, C. Meng, S. Pei, Y.M. Peng, J.R. Zhang, P. Zhang, Z.S. Zhou
IHEP, Beijing, People's Republic of China

Abstract The High Energy Photon Source (HEPS) will be constructed in the following few years. The light source is comprised of an ultra-low emittance storage ring and a full energy injector. The energy of the storage ring is 6 GeV. The injector is comprised of a 500 MeV linac, a 500 MeV to 6 GeV booster synchrotron and transport lines connecting the machines. In the present design, the linac uses normal conducting S-band bunching and accelerating structures. The booster adopts FODO cells, has a circumference of about 454 m and an emittance lower than 40 nmrad. The injector can provide a single-bunch charge up to 2 nC at 6 GeV for the storage ring. This paper briefly introduces the conceptual design of the injector of the HEPS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF058

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TUPMF062

Status of HEPS Booster Lattice Design and Physics Studies

1407

Y.M. Peng, Z. Duan, Y.Y. Guo, D. Ji, Y. Jiao, J.L. Li, C. Meng, S.K. Tian, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) with an ul-tralow emittance is proposed to be built in Beijing, Chi-na. It will utilize a booster as its full energy injector. On-axis swap-out injection is chosen as the baseline injec-tion scheme for the storage ring. As required by the stor-age ring, a beam with a bunch charge up to 2.5 nC is needed to be injected in the booster. However, limited by the transverse mode coupling instability (TMCI), such a high bunch charge is challenging. To overcome this problem, a lattice with a considerable large momentum compaction factor is designed. This paper reports the lattice design and physics studies of the HEPS booster, including injection and extraction design, error studies, eddy current effects, collective effects, and so on.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-TUPMF062

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WEPMF032

Experimental Studies on Secondary Electron Emission Characteristics for Chamber Materials of Accelerators

2425

Y. Jiao, Z. Duan, W.B. Liu, Y.D. Liu
IHEP, Beijing, People's Republic of China
Liu. S. Liu
Institute of High Energy Physics (IHEP), People's Republic of China
P.C. Wang
DNSC, Dongguan, People's Republic of China

Funding: National Natural Science Foundation of China (11275221) and Key Laboratory Foundation of Particle Acceleration Physics &Technology (Y5294106TD)
Secondary electron emission (SEE) of surface is origin of multipacting effect which could seriously deteriorate beam quality and even perturb the normal operation of particle accelerators. Experimental measurements on secondary electron yield (SEY) on different materials and coating have been developed in many accelerator laboratory. In fact, the SEY is just one parameter of secondary electron emission characteristics which include spatial and energy distribution of emitted electrons. A novel experimental apparatus was set up in China Spallation Neutron Source (CSNS) and innovative measurement methods were applied to obtain the whole characteristics of SEE. With some traditional accelerator chamber materials such as Cu, Al, TiN, SEY dependence on primary electron energy and beam injection angle, spatial and energy distribution of emitted secondary electrons were achieved with this measurement apparatus. This contribution also tries to give all the experimental results a reasonable theoretical analysis.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPMF032

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WEPML069

Fast Kicker and Pulser R&D for the HEPS on-Axis Injection System

2846

H. Shi, J. Chen, Z. Duan, L. Huo, P. Liu, X.L. Shi, G. Wang, L. Wang, N. Wang
IHEP, Beijing, People's Republic of China

The HEPS plans to adopt on-axis injection scheme because the dynamic aperture of machine is not large enough for off-axis injection for its baseline 7BA lattice design. A sets of super fast kicker and pulser of ±15kV amplitude, 15ns pulse bottom width are needed for bunch spacing of 10ns to minimize perturbation on adjacent bunches. To achieve these requirement, a multifaceted R&D program including the strip-line kicker and HV pulser, was initiated last 2 years. So far, the prototype development of a 750mm long strip-line kicker and a DSRD pulser was completed and the preliminary test results show they can meet the baseline requirement of the HEPS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPML069

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THPAF014

Studies of the Single-Bunch Instabilities in the Booster of HEPS

2971

H.S. Xu, Z. Duan, J.L. Li, Y.M. Peng, S.K. Tian, N. Wang
IHEP, Beijing, People's Republic of China

High Energy Photon Source (HEPS), which is proposed in China, is an ultra-low emittance storage ring based synchrotron light source. Because of the requirement of the relatively high single-bunch charge, the booster may suffer from the single-bunch instabilities. A preliminary impedance model has been developed for the studies of collective instabilities in the booster. Based on this impedance model, the longitudinal and transverse single-bunch instabilities have been studied.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAF014

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THPAK014

Analytical Estimation of the Beam Ion Instability in HEPS

3231

N. Wang, Z. Duan, S.K. Tian, H.S. Xu
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a new designed photon source at beam energy of 6 GeV, with natural beam emittance less than 100pm. Due to the small transverse beam size, beam ion instability is one of the potential issues for HEPS. The growth time of the instability is estimated analytically for different operation scenarios. The results show considerably good agreement with the wake strong simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK014

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THPAK015

Impedance and Heat Load Analysis of the Stripline Kicker in HEPS

3234

N. Wang, J. Chen, Z. Duan, H. Shi, S.K. Tian, L. Wang, H.S. Xu
IHEP, Beijing, People's Republic of China

In the High Energy Photon Source (HEPS), strip-line kickers are adopted for beam injection and extraction. Beam coupling impedance contribution from the strip-line kicker is calculated. Detailed studies on the heat load dissipation have been performed. The peak electric field on the blade and the induced voltage on the feedthroughs due to the beam passage are also calculated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK015

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THPAK016

Measurement and Analysis of Synchrotron Tune Variation with Beam Current in BEPCII

3237

N. Wang, Z. Duan, G. Xu, H.S. Xu, C.H. Yu, Y. Zhang
IHEP, Beijing, People's Republic of China

Coherent synchrotron frequency shift is observed during machine studies in BEPCII (Beijing Electron Positron Collider Upgrade). The results show that the synchrotron frequency varies parabolically with the increase of the beam current. This phenomenon is supposed to be induced by the interaction of the beam with the fundamental mode of the accelerating cavity. In order to explain this phenomenon, a simple physical model is developed from the couple bunch instability theory. The analytical estimations based on the physical model show good agreement with the measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK016

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THPMF052

The Swap-Out Injection Scheme for the High Energy Photon Source

4178

Z. Duan, J. Chen, Y.Y. Guo, Y. Jiao, J.L. Li, Y.M. Peng, J.Q. Wang, N. Wang, G. Xu, H.S. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China (No.11605212).
The on-axis swap-out scheme is a promising injection scheme for di raction-limited storage rings, since it only re- quires a rather small dynamic aperture and thus potentially allows a higher brightness compared to traditional o -axis injection schemes. However, a full charge injector is neces- sary for this scheme and its design can be nontrivial, in par- ticular to satisfy the large single bunch charge requirements in special lling patterns for timing experiments. In the High Energy Photon Source, we propose using the booster also as a high energy accumulator ring to recapture the spent bunches extracted from the storage ring, so as to relax the challenges in generation and acceleration of bunches with a high charge, and as a cost-e ective solution compared to building a dedicated full energy accumulator ring. In this paper, the beam dynamics issues of this scheme will be presented, trade-o s between the storage ring and booster beam parameters and hardware specifications will also be discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF052

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THPMF053

Study of the Dynamic Aperture Reduction Due to Error Effects for the High Energy Photon Source

4182

Z. Duan, D. Ji, Y. Jiao
IHEP, Beijing, People's Republic of China

Funding: Work supported by Natural Science Foundation of China(No.11605212).
The 6 GeV High Energy Photon Source (HEPS) employs a lattice of 48 hybrid 7BA cells, aims to achieve a natural emittance between 30 to 60 pm, within a circumference of about 1.3 km. In the performance evaluation of optimized lattices, we found that the dynamic aperture of the bare lat- tice were su cient for on-axis swap-out injection, but a large reduction in the dynamic aperture was observed in the simu- lation when including lattice imperfections and even after dedicated lattice corrections. In this paper, we identi ed the feed-down e ects of sextupoles as the major source of DA reduction, and proposed to use dedicated sextupole movers to e ciently reduce the orbit o sets in sextupoles, to par- tially recover the dynamic aperture, sextupole mover-based optics correction schemes were also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF053

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THPMF054

Beam Performance Simulation with Error Effects and Correction on HEPS Design

4186

D. Ji, X. Cui, Z. Duan, Y. Jiao, Y. Wei, Y.L. Zhao
IHEP, Beijing, People's Republic of China

The High Energy Photon Source (HEPS) is a 6-GeV, ul-tralow-emittance kilometre-scale storage ring light source to be built in China. In this paper, the progress of the error and correction effect study on HEPS over the past one year will be presented, including error requirement and correction progress update. And beam performance eval-uation with static error and correction on orbit, optics, emittance and dynamic aperture will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMF054

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