SAP2023 - List of Keywords (coupling)

Paper	Title	Other Keywords	Page
MOCXA02	Beam-Beam Interaction with Longitudinal Impedance and Its Application in TMCI Study	impedance, synchrotron, simulation, electron	1
	C.T. Lin IASF, Shenzhen, Guangdong, People’s Republic of China K. Ohmi KEK, Ibaraki, Japan Y. Zhang IHEP, Beijing, People’s Republic of China
	Simulations have showed a novel coherent head-tail instability induced by beam-beam interaction with a large Piwinski angle. The localized cross-wake force has been introduced to explain the instability. The longitudinal impedance would cause coherent and incoherent synchrotron tune shift and distort the particle¿s trajectories in longitudinal phase space. Further beam-beam simulation revealed that the longitudinal impedance has strong impacts on the beam stability, squeezing the horizontal stable tune area seriously. The instability has become an important issue during the designs of CEPC and FCC-ee. In this paper, we develop a transverse mode coupling analysis method that could be used to study beam-beam instability with and without longitudinal impedance. This method can also be applied in synchrotron light sources to study transverse mode coupling instability (TMCI) with longitudinal impedance and harmonic cavity. Some preliminary results at Shenzhen Innovation Light Source (SILF) are also shown.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOCXA02
About •	Received ※ 30 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 23 September 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB010	Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance	impedance, vacuum, ECR, storage-ring	30
	T.L. He, Z.H. Bai, W.W. Li, H. Xu USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In diffraction-limited storage rings, non-evaporable getter (NEG) coatings are generally used to assure the ultrahigh vacuum, which, however, also increase the beam coupling impedance that can affect beam dynamics. Ignoring the influence of coating roughness, the impact of NEG coatings on the impedance mainly depends on the coating thickness and resistivity. In this paper, we investigate the impedance characteristics of a round CuCrZr vacuum chamber coated by NEG with different thickness and resistivity.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB010
About •	Received ※ 29 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 12 August 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB014	Development of a Vlasov Solver for Arbitrary Sub-optimal Lengthening Conditions in Double-RF System	synchrotron, impedance, betatron, cavity	34
	J.Y. Xu, N. Wang, H.S. Xu, Y. Zhang IHEP, Beijing, People’s Republic of China C.T. Lin IASF, Shenzhen, Guangdong, People’s Republic of China
	Solving Vlasov equation is a classic method for analyzing collective beam instabilities. Considering longitudinal impedance and the nonlinear longitudinal potential well, we developed a new Vlasov solver which can be used to study the transverse mode-coupling instability under the arbitrary sub-optimal lengthening and the optimal lengthening conditions in a double-RF system. Several different techniques to deal with the radial direction of longitudinal phase space have been tested. Numerical discretization method is selected in this paper. The development of the solver is presented in details here. Benchmarks and crosscheck of the solver have been made and presented as well.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB014
About •	Received ※ 30 June 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 21 August 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB030	Physical Design of an S-Band Cold Cathode RF Gun	gun, cavity, cathode, electron	70
	T.H. He, H. Xu, K. Zhou, Z. Zhou CAEP/IAE, Mianyang, Sichuan, People’s Republic of China
	In recent years, the properties of new field emission materials have been gradually improved with the advancement of materials research fields, which have provided the possibility for the research and realization of cold cathode RF guns. A 0.32+1 cell S-band RF gun was designed based on the emission properties of carbon nanotube films and ultra nano diamond films. This article mainly introduces the selection of electron gun cavity, RF design and corresponding thermal analysis. The physical design results basically meet the design requirements.
	Poster MOPB030 [1.010 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB030
About •	Received ※ 28 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 21 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPB039	Low-Alpha Storage Ring Design for Steady-State Microbunching to Generate EUV Radiation	storage-ring, radiation, lattice, electron	88
	Z. Pan, A. Chao, X.J. Deng, W.-H. Huang, Z.Z. Li, C.-X. Tang TUB, Beijing, People’s Republic of China
	A new concept is proposed for minimizing the longitudinal emittance of a low momentum compaction factor (low-alpha) storage ring which has the capability to stably store sub-femtosecond electron bunches for the first time. This storage ring is designed for Steady-State microbunching (SSMB) to generate kW level average power EUV radiation. The proposed design approach can be applied to any quasi-isochronous storage rings to yield very high radiation power due to longitudinal coherence of the radiation. We obtain an optimal lattice design by minimizing global and local momentum compaction factors simultaneously and the result of single-particle tracking shows that the electron beam with equilibrium rms bunch length of about 40 nm can be stored in this ring. Nonlinear dynamics is studied for this lattice.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB039
About •	Received ※ 03 July 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 31 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB016	High-Fidelity Modeling and Transmission Optimization for the Beamline of HUST-PTF	proton, simulation, beam-transport, vacuum	117
	Y.C. Chen, C.L. Liu, X. Liu, B. Qin, W. Wang HUST, Wuhan, People’s Republic of China
	A superconducting cyclotron-based proton therapy facility is under construction at Huazhong University of Science and Technology (HUST-PTF). In previous works, the vacuum chamber’s shape and the tail effect of the energy spectrum are not considered when calculating the transmission efficiency of the beamline. This study proposes a high-fidelity modeling and optimization method for the HUST-PTF beamline based on Monte Carlo simulation using BDSIM. The modeling procedure of the beamline based on BDSIM is briefly introduced. Then verification of the optical parameters are performed on the gantry sections, and the transmission efficiency of the gantry is optimized by analyzing the unexpected beam loss. After optimization, the transmission efficiency at each energy setting point is calculated. The simulation results show that (1) the proposed optimization method improves the gantry’s transmission efficiency from 92.4% to 95.6%; (2) the transmission efficiency calculated by high-fidelity modeling is more accurate than previous simulations because the beam-matter interaction and practical vacuum chamber geometry are considered.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB016
About •	Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 09 February 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOCXA02

Beam-Beam Interaction with Longitudinal Impedance and Its Application in TMCI Study

impedance, synchrotron, simulation, electron

1

C.T. Lin
IASF, Shenzhen, Guangdong, People’s Republic of China
K. Ohmi
KEK, Ibaraki, Japan
Y. Zhang
IHEP, Beijing, People’s Republic of China

Simulations have showed a novel coherent head-tail instability induced by beam-beam interaction with a large Piwinski angle. The localized cross-wake force has been introduced to explain the instability. The longitudinal impedance would cause coherent and incoherent synchrotron tune shift and distort the particle¿s trajectories in longitudinal phase space. Further beam-beam simulation revealed that the longitudinal impedance has strong impacts on the beam stability, squeezing the horizontal stable tune area seriously. The instability has become an important issue during the designs of CEPC and FCC-ee. In this paper, we develop a transverse mode coupling analysis method that could be used to study beam-beam instability with and without longitudinal impedance. This method can also be applied in synchrotron light sources to study transverse mode coupling instability (TMCI) with longitudinal impedance and harmonic cavity. Some preliminary results at Shenzhen Innovation Light Source (SILF) are also shown.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOCXA02

About •

Received ※ 30 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 23 September 2024

Cite •

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

MOPB010

Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance

impedance, vacuum, ECR, storage-ring

30

T.L. He, Z.H. Bai, W.W. Li, H. Xu
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In diffraction-limited storage rings, non-evaporable getter (NEG) coatings are generally used to assure the ultrahigh vacuum, which, however, also increase the beam coupling impedance that can affect beam dynamics. Ignoring the influence of coating roughness, the impact of NEG coatings on the impedance mainly depends on the coating thickness and resistivity. In this paper, we investigate the impedance characteristics of a round CuCrZr vacuum chamber coated by NEG with different thickness and resistivity.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB010

About •

Received ※ 29 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 12 August 2024

Cite •

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

MOPB014

Development of a Vlasov Solver for Arbitrary Sub-optimal Lengthening Conditions in Double-RF System

synchrotron, impedance, betatron, cavity

34

J.Y. Xu, N. Wang, H.S. Xu, Y. Zhang
IHEP, Beijing, People’s Republic of China
C.T. Lin
IASF, Shenzhen, Guangdong, People’s Republic of China

Solving Vlasov equation is a classic method for analyzing collective beam instabilities. Considering longitudinal impedance and the nonlinear longitudinal potential well, we developed a new Vlasov solver which can be used to study the transverse mode-coupling instability under the arbitrary sub-optimal lengthening and the optimal lengthening conditions in a double-RF system. Several different techniques to deal with the radial direction of longitudinal phase space have been tested. Numerical discretization method is selected in this paper. The development of the solver is presented in details here. Benchmarks and crosscheck of the solver have been made and presented as well.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB014

About •

Received ※ 30 June 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 21 August 2024

Cite •

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

MOPB030

Physical Design of an S-Band Cold Cathode RF Gun

gun, cavity, cathode, electron

70

T.H. He, H. Xu, K. Zhou, Z. Zhou
CAEP/IAE, Mianyang, Sichuan, People’s Republic of China

In recent years, the properties of new field emission materials have been gradually improved with the advancement of materials research fields, which have provided the possibility for the research and realization of cold cathode RF guns. A 0.32+1 cell S-band RF gun was designed based on the emission properties of carbon nanotube films and ultra nano diamond films. This article mainly introduces the selection of electron gun cavity, RF design and corresponding thermal analysis. The physical design results basically meet the design requirements.

Poster MOPB030 [1.010 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB030

About •

Received ※ 28 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 21 November 2023

Cite •

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

MOPB039

Low-Alpha Storage Ring Design for Steady-State Microbunching to Generate EUV Radiation

storage-ring, radiation, lattice, electron

88

Z. Pan, A. Chao, X.J. Deng, W.-H. Huang, Z.Z. Li, C.-X. Tang
TUB, Beijing, People’s Republic of China

A new concept is proposed for minimizing the longitudinal emittance of a low momentum compaction factor (low-alpha) storage ring which has the capability to stably store sub-femtosecond electron bunches for the first time. This storage ring is designed for Steady-State microbunching (SSMB) to generate kW level average power EUV radiation. The proposed design approach can be applied to any quasi-isochronous storage rings to yield very high radiation power due to longitudinal coherence of the radiation. We obtain an optimal lattice design by minimizing global and local momentum compaction factors simultaneously and the result of single-particle tracking shows that the electron beam with equilibrium rms bunch length of about 40 nm can be stored in this ring. Nonlinear dynamics is studied for this lattice.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB039

About •

Received ※ 03 July 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 31 December 2023

Cite •

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

TUPB016

High-Fidelity Modeling and Transmission Optimization for the Beamline of HUST-PTF

proton, simulation, beam-transport, vacuum

117

Y.C. Chen, C.L. Liu, X. Liu, B. Qin, W. Wang
HUST, Wuhan, People’s Republic of China

A superconducting cyclotron-based proton therapy facility is under construction at Huazhong University of Science and Technology (HUST-PTF). In previous works, the vacuum chamber’s shape and the tail effect of the energy spectrum are not considered when calculating the transmission efficiency of the beamline. This study proposes a high-fidelity modeling and optimization method for the HUST-PTF beamline based on Monte Carlo simulation using BDSIM. The modeling procedure of the beamline based on BDSIM is briefly introduced. Then verification of the optical parameters are performed on the gantry sections, and the transmission efficiency of the gantry is optimized by analyzing the unexpected beam loss. After optimization, the transmission efficiency at each energy setting point is calculated. The simulation results show that (1) the proposed optimization method improves the gantry’s transmission efficiency from 92.4% to 95.6%; (2) the transmission efficiency calculated by high-fidelity modeling is more accurate than previous simulations because the beam-matter interaction and practical vacuum chamber geometry are considered.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB016

About •

Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 09 February 2024

Cite •

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