IPAC2021 - List of Authors (Bai, Z.H.)

Paper	Title	Page
MOPAB074	Preliminary Study of Design Method for Hybrid MBA Lattice	297
	J.J. Tan, Z.H. Bai, Z.L. Ren, J.H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China Q. Zhang INEST, Hefei, People’s Republic of China
	Nonlinear optimization of hybrid multi-bend-achromat (HMBA) lattice is a difficult task due to its quite limited variables of multipole magnets. As a result, it is necessary to consider nonlinear potential of the lattice in its linear design. Nonlinear dynamics can be estimated by nonlinear driving terms and detuning terms. In this paper, we propose a design method for HMBA lattice. In this method, objective functions include emittance and two indicators of nonlinear dynamics, which consist of nonlinear driving terms and detuning terms. As an example, an HMBA lattice for a 2.2 GeV storage ring with circumference of 460.8 m was designed to demonstrate the method.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB074
About •	paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 21 August 2021
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MOPAB112	A Modified Hybrid 6BA Lattice for the HALF Storage Ring	407
	Z.H. Bai, G.Y. Feng, T.L. He, W. Li, W.W. Li, G. Liu, Z.L. Ren, L. Wang, P.H. Yang, S.C. Zhang, T. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In this paper, we propose a modified hybrid 6BA lattice as the baseline lattice of the Hefei Advanced Light Facility (HALF) storage ring. Similar to the Diamond-II lattice, the proposed lattice cell has one long straight section and one mid-straight section; but the two bend units adjacent to the mid-straight are LGB/RB units (LGB: longitudinal gradient bend, RB: reverse bend), which can give both lower emittance and shorter damping times. The designed HALF storage ring, with an energy of 2.2 GeV and 20 lattice cells, has a natural emittance of about 85 pm·rad.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB112
About •	paper received ※ 15 May 2021 paper accepted ※ 20 May 2021 issue date ※ 01 September 2021
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MOPAB113	A Low-emittance Booster Lattice Design for the SOLEIL Upgrade	410
	M.-A. Tordeux, A. Loulergue, R. Nagaoka SOLEIL, Gif-sur-Yvette, France Z.H. Bai, G. Liu, T. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	The SOLEIL storage ring upgrade will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, the present booster also needs to be upgraded, aiming to reduce the emittance below 10 nm·rad. A multi-bend achromat lattice is designed in this context for the booster upgrade, which consists of two superperiods to respect the present race-track configuration. The lattice is a 16BA HOA (Higher-Order Achromat) type lattice, composed of 14 unit cells, 2 matching cells and a long straight section, and combined-function bending magnets are used in the unit cells to both save space and reduce the emittance. The natural emittance of the designed booster is 5.2 nm·rad at the final energy of 2.75 GeV. This paper presents the general constraints, linear lattice design and nonlinear dynamics optimization for the booster upgrade.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB113
About •	paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 26 August 2021
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MOPAB242	A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring	782
	J. Li, M. Abo-Bakr, P. Goslawski HZB, Berlin, Germany Z.H. Bai USTC/NSRL, Hefei, Anhui, People’s Republic of China
	HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242
About •	paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021
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TUPAB265	Bunch Lengthening of the HALF Storage Ring in the Presence of Passive Harmonic Cavities	2082
	T.L. He, Z.H. Bai, G.Y. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	A passive 3^rd harmonic RF system, being necessary for the Hefei Advanced Light Facility (HALF) storage ring under design, will be employed to lengthen the bunches for suppressing the intrabeam scattering and improving the beam lifetime. However, the transient beam loading due to the fundamental mode may significantly reduce the bunch lengthening. Since the scale of transient effects is proportional to R/Q, the effects of R/Q on bunch lengthening, in uniform fill pattern with the near-optimum condition fulfilled, are analyzed by multibunches multiparticles tracking simulation. It indicates that the passive superconducting harmonic cavity with a lower R/Q is preferred by HALF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB265
About •	paper received ※ 16 May 2021 paper accepted ※ 18 June 2021 issue date ※ 20 August 2021
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TUPAB266	Periodic Transient Beam Loading Effects Predicted by a Semi-Analytical Method	2086
	T.L. He, Z.H. Bai, G. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In this paper, we improve a semi-analytical method, which can be not only used for bunch lengthening under equilibrium conditions, but also applied to the prediction of a periodic transient beam loading effect. This periodic transient is induced by the presence of the passive harmonic cavity and might be encountered under specific conditions for a ultra-low emittance storage ring with a higher beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB266
About •	paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021
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WEPAB263	Complex Unit Lattice Cell for Low-Emittance Synchrotrons	3254
	Z.L. Ren, Z.H. Bai, J.J. Tan, L. Wang, H. Xu, P.H. Yang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	To reach the real diffraction-limited emittance, it is generally required to increase the number of bends in multi-bend achromat (MBA) lattices that are used in the designs of fourth-generation synchrotron light sources. For an MBA lattice with distributed chromatic correction, more bends mean much tighter space and much stronger magnets. Inspired by the hybrid MBA lattice concept, in this paper we propose a new lattice concept called complex unit lattice cell, which can save space and reduce magnet strengths. A 17BA lattice based on the complex unit cell concept is designed for a 3 GeV synchrotron light source with a circumference of 537.6 m, which reaches a natural emittance of about 21 pm·rad. Comparison is also made between this 17BA lattice and the 17BA lattice with distributed chromatic correction to demonstrate the merit of the complex unit cell concept.
	Poster WEPAB263 [1.279 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB263
About •	paper received ※ 16 May 2021 paper accepted ※ 02 July 2021 issue date ※ 12 August 2021
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WEPAB264	MOGA Optimization of Superconducting Longitudinal Gradient Bend Based on NbTi Wire	3257
	C. Chen, Z.H. Bai, G.Y. Feng, Z.L. Ren, Zh.X. Tang, L. Wang, H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	Funding: Work supported by National Key Research and Development Program of China, (2016YFA0402001) Multi-bend achromat lattices with unit cells have been used in diffraction-limited storage ring designs. The longitudinal gradient bend can reduce the horizontal emittance below the theoretical minimum of a given magnet structure, and generally the horizontal emittance reduces with the peak field grows. Therefore superconducting longitudinal gradient bend (SLGB) can produce higher peak field value and quasi-hyperbolic field profile to minimize emittance at location of radiation and generate better hard X-rays. NbTi conductor, rather than Nb₃Sn conductor, is selected to keep the design and manufacture of SLGB magnet as simple as possible. In this paper, how the field profiles of race-track type coil and solenoid coil change with their geometric parameters is studied, and multi-objective genetic algorithm is used to optimize SLGB magnet structure considering Hefei Advanced Light Facility lattice design demand and NbTi critical current.
	Poster WEPAB264 [1.476 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB264
About •	paper received ※ 14 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021
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THPAB073	Study of Seven-Bend-Achromat Lattice Option for Half	3926
	J.H. Xu, Z.H. Bai, Z.L. Ren, J.J. Tan, P.H. Yang USTC/NSRL, Hefei, Anhui, People’s Republic of China Q. Zhang INEST, Hefei, People’s Republic of China
	A seven-bend-achromat (7BA) storage ring lattice design for Hefei Advanced Light Facility (HALF) with a beam energy of 2.2 GeV and a circumference of 388.8 m is presented. The 7BA lattice is designed with the combined function bends and reverse bends which has a natural emittance of about 67 pm·rad. Two lattice candidates with different tunes have been selected. One lattice has better nonlinear dynamic performance for off-axis injection. The other lattice provides lower beta functions at the center of straight sections. The results of these studies are discussed in this paper.
	Poster THPAB073 [1.146 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB073
About •	paper received ※ 15 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Preliminary Study of Design Method for Hybrid MBA Lattice

297

J.J. Tan, Z.H. Bai, Z.L. Ren, J.H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Q. Zhang
INEST, Hefei, People’s Republic of China

Nonlinear optimization of hybrid multi-bend-achromat (HMBA) lattice is a difficult task due to its quite limited variables of multipole magnets. As a result, it is necessary to consider nonlinear potential of the lattice in its linear design. Nonlinear dynamics can be estimated by nonlinear driving terms and detuning terms. In this paper, we propose a design method for HMBA lattice. In this method, objective functions include emittance and two indicators of nonlinear dynamics, which consist of nonlinear driving terms and detuning terms. As an example, an HMBA lattice for a 2.2 GeV storage ring with circumference of 460.8 m was designed to demonstrate the method.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB074

About •

paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 21 August 2021

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

MOPAB112

A Modified Hybrid 6BA Lattice for the HALF Storage Ring

407

Z.H. Bai, G.Y. Feng, T.L. He, W. Li, W.W. Li, G. Liu, Z.L. Ren, L. Wang, P.H. Yang, S.C. Zhang, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In this paper, we propose a modified hybrid 6BA lattice as the baseline lattice of the Hefei Advanced Light Facility (HALF) storage ring. Similar to the Diamond-II lattice, the proposed lattice cell has one long straight section and one mid-straight section; but the two bend units adjacent to the mid-straight are LGB/RB units (LGB: longitudinal gradient bend, RB: reverse bend), which can give both lower emittance and shorter damping times. The designed HALF storage ring, with an energy of 2.2 GeV and 20 lattice cells, has a natural emittance of about 85 pm·rad.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB112

About •

paper received ※ 15 May 2021 paper accepted ※ 20 May 2021 issue date ※ 01 September 2021

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MOPAB113

A Low-emittance Booster Lattice Design for the SOLEIL Upgrade

410

M.-A. Tordeux, A. Loulergue, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France
Z.H. Bai, G. Liu, T. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

The SOLEIL storage ring upgrade will require an injected beam with small transverse and longitudinal sizes. To meet this requirement, the present booster also needs to be upgraded, aiming to reduce the emittance below 10 nm·rad. A multi-bend achromat lattice is designed in this context for the booster upgrade, which consists of two superperiods to respect the present race-track configuration. The lattice is a 16BA HOA (Higher-Order Achromat) type lattice, composed of 14 unit cells, 2 matching cells and a long straight section, and combined-function bending magnets are used in the unit cells to both save space and reduce the emittance. The natural emittance of the designed booster is 5.2 nm·rad at the final energy of 2.75 GeV. This paper presents the general constraints, linear lattice design and nonlinear dynamics optimization for the booster upgrade.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB113

About •

paper received ※ 19 May 2021 paper accepted ※ 28 May 2021 issue date ※ 26 August 2021

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

MOPAB242

A Six-Bend-Achromat Lattice for a 2.5 GeV Diffraction-Limited Storage Ring

782

J. Li, M. Abo-Bakr, P. Goslawski
HZB, Berlin, Germany
Z.H. Bai
USTC/NSRL, Hefei, Anhui, People’s Republic of China

HZB has proposed a 2.5 GeV diffraction-limited storage ring as the upgrade of BESSY II. A Six-Bend-Achromat lattice based on Higher-Order Achromat, as one of the possible solutions, has been designed to meet the requirements of low emittance, compact layout, large dynamic aperture and large momentum acceptance. The linear lattice design and the nonlinear performance are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB242

About •

paper received ※ 18 May 2021 paper accepted ※ 09 June 2021 issue date ※ 17 August 2021

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

TUPAB265

Bunch Lengthening of the HALF Storage Ring in the Presence of Passive Harmonic Cavities

2082

T.L. He, Z.H. Bai, G.Y. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

A passive 3^rd harmonic RF system, being necessary for the Hefei Advanced Light Facility (HALF) storage ring under design, will be employed to lengthen the bunches for suppressing the intrabeam scattering and improving the beam lifetime. However, the transient beam loading due to the fundamental mode may significantly reduce the bunch lengthening. Since the scale of transient effects is proportional to R/Q, the effects of R/Q on bunch lengthening, in uniform fill pattern with the near-optimum condition fulfilled, are analyzed by multibunches multiparticles tracking simulation. It indicates that the passive superconducting harmonic cavity with a lower R/Q is preferred by HALF.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB265

About •

paper received ※ 16 May 2021 paper accepted ※ 18 June 2021 issue date ※ 20 August 2021

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

TUPAB266

Periodic Transient Beam Loading Effects Predicted by a Semi-Analytical Method

2086

T.L. He, Z.H. Bai, G. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In this paper, we improve a semi-analytical method, which can be not only used for bunch lengthening under equilibrium conditions, but also applied to the prediction of a periodic transient beam loading effect. This periodic transient is induced by the presence of the passive harmonic cavity and might be encountered under specific conditions for a ultra-low emittance storage ring with a higher beam current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB266

About •

paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021

Export •

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

WEPAB263

Complex Unit Lattice Cell for Low-Emittance Synchrotrons

3254

Z.L. Ren, Z.H. Bai, J.J. Tan, L. Wang, H. Xu, P.H. Yang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

To reach the real diffraction-limited emittance, it is generally required to increase the number of bends in multi-bend achromat (MBA) lattices that are used in the designs of fourth-generation synchrotron light sources. For an MBA lattice with distributed chromatic correction, more bends mean much tighter space and much stronger magnets. Inspired by the hybrid MBA lattice concept, in this paper we propose a new lattice concept called complex unit lattice cell, which can save space and reduce magnet strengths. A 17BA lattice based on the complex unit cell concept is designed for a 3 GeV synchrotron light source with a circumference of 537.6 m, which reaches a natural emittance of about 21 pm·rad. Comparison is also made between this 17BA lattice and the 17BA lattice with distributed chromatic correction to demonstrate the merit of the complex unit cell concept.

Poster WEPAB263 [1.279 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB263

About •

paper received ※ 16 May 2021 paper accepted ※ 02 July 2021 issue date ※ 12 August 2021

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

WEPAB264

MOGA Optimization of Superconducting Longitudinal Gradient Bend Based on NbTi Wire

3257

C. Chen, Z.H. Bai, G.Y. Feng, Z.L. Ren, Zh.X. Tang, L. Wang, H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

Funding: Work supported by National Key Research and Development Program of China, (2016YFA0402001)
Multi-bend achromat lattices with unit cells have been used in diffraction-limited storage ring designs. The longitudinal gradient bend can reduce the horizontal emittance below the theoretical minimum of a given magnet structure, and generally the horizontal emittance reduces with the peak field grows. Therefore superconducting longitudinal gradient bend (SLGB) can produce higher peak field value and quasi-hyperbolic field profile to minimize emittance at location of radiation and generate better hard X-rays. NbTi conductor, rather than Nb₃Sn conductor, is selected to keep the design and manufacture of SLGB magnet as simple as possible. In this paper, how the field profiles of race-track type coil and solenoid coil change with their geometric parameters is studied, and multi-objective genetic algorithm is used to optimize SLGB magnet structure considering Hefei Advanced Light Facility lattice design demand and NbTi critical current.

Poster WEPAB264 [1.476 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB264

About •

paper received ※ 14 May 2021 paper accepted ※ 05 July 2021 issue date ※ 14 August 2021

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

THPAB073

Study of Seven-Bend-Achromat Lattice Option for Half

3926

J.H. Xu, Z.H. Bai, Z.L. Ren, J.J. Tan, P.H. Yang
USTC/NSRL, Hefei, Anhui, People’s Republic of China
Q. Zhang
INEST, Hefei, People’s Republic of China

A seven-bend-achromat (7BA) storage ring lattice design for Hefei Advanced Light Facility (HALF) with a beam energy of 2.2 GeV and a circumference of 388.8 m is presented. The 7BA lattice is designed with the combined function bends and reverse bends which has a natural emittance of about 67 pm·rad. Two lattice candidates with different tunes have been selected. One lattice has better nonlinear dynamic performance for off-axis injection. The other lattice provides lower beta functions at the center of straight sections. The results of these studies are discussed in this paper.

Poster THPAB073 [1.146 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB073

About •

paper received ※ 15 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021

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