HB2023 - List of Authors (Yuan, Y.S.)

Paper	Title	Page
TUA1C2	Coherent Dispersion Effects in 2-D Coasting Beams and 3-D Bunched Beams in High-Intensity Hadron Synchrotrons
	Y.S. Yuan IHEP, Beijing, People’s Republic of China G. Franchetti GSI, Darmstadt, Germany
	Both space charge and dispersion have an effect on high intensity beams in circular accelerators or transport sections with bending magnets, and may lead to emittance growth or even beam loss. In this work we study the combined effect of dispersion and space charge on both 2-D and 3-D high-intensity beams. Based on 2-D envelope equations extended by dispersion, and particle-in-cell simulations, we investigate the mismatched oscillation and coherent instabilities in an rms self-consistent manner. Main characteristics of the space-charge modified dispersion are discussed. It is found that the parametric and confluent resonances in 90 deg envelope insatiability can be separated because of dispersion. The recently-discovered 120 deg dispersion instability is also detailed discussed. For 3-D bunched beams, a splitting effect on dispersion mode and side bands of envelope modes due to synchrotron motion are presented. The mechanism of the splitting effect on the dispersion mode with space charge is analyzed. Moreover, the 120 deg dispersion instability in the 3-D bunched beam are presented with a discussion on possible methods for measuring the dispersion mode in hadron synchrotrons.
	Slides TUA1C2 [1.499 MB]
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TUA4C2	Application of Programmable Trim Quadrupoles in Beam Commissioning of CSNS/RCS	158
	Y. Li, C.D. Deng, S.Y. Xu DNSC, Dongguan, People’s Republic of China Y.W. An, X. Qi, S. Wang, Y.S. Yuan IHEP, Beijing, People’s Republic of China H.Y. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) achieved its design power of 100 kW in 2020 and is currently stably operating at 140 kW after a series of measures. In the process of increasing beam power, 16 programmable trim quadrupoles were installed in the Rapid Cycling Synchrotron (RCS) of CSNS to enable rapid variation of tunes, effective adjustment of Twiss parameters, and restoration of lattice superperiodicity through the machine cycle. This paper provides a detailed introduction to the design of the trim quadrupoles and preliminary results of the machine study. The beam experiments show that the trim quadrupoles play a crucial role in increasing beam power after exceeding 100 kW.
	Slides TUA4C2 [4.136 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C2
About •	Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 22 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUA1C2

Coherent Dispersion Effects in 2-D Coasting Beams and 3-D Bunched Beams in High-Intensity Hadron Synchrotrons

Y.S. Yuan
IHEP, Beijing, People’s Republic of China
G. Franchetti
GSI, Darmstadt, Germany

Both space charge and dispersion have an effect on high intensity beams in circular accelerators or transport sections with bending magnets, and may lead to emittance growth or even beam loss. In this work we study the combined effect of dispersion and space charge on both 2-D and 3-D high-intensity beams. Based on 2-D envelope equations extended by dispersion, and particle-in-cell simulations, we investigate the mismatched oscillation and coherent instabilities in an rms self-consistent manner. Main characteristics of the space-charge modified dispersion are discussed. It is found that the parametric and confluent resonances in 90 deg envelope insatiability can be separated because of dispersion. The recently-discovered 120 deg dispersion instability is also detailed discussed. For 3-D bunched beams, a splitting effect on dispersion mode and side bands of envelope modes due to synchrotron motion are presented. The mechanism of the splitting effect on the dispersion mode with space charge is analyzed. Moreover, the 120 deg dispersion instability in the 3-D bunched beam are presented with a discussion on possible methods for measuring the dispersion mode in hadron synchrotrons.

Slides TUA1C2 [1.499 MB]

Cite •

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

TUA4C2

Application of Programmable Trim Quadrupoles in Beam Commissioning of CSNS/RCS

158

Y. Li, C.D. Deng, S.Y. Xu
DNSC, Dongguan, People’s Republic of China
Y.W. An, X. Qi, S. Wang, Y.S. Yuan
IHEP, Beijing, People’s Republic of China
H.Y. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) achieved its design power of 100 kW in 2020 and is currently stably operating at 140 kW after a series of measures. In the process of increasing beam power, 16 programmable trim quadrupoles were installed in the Rapid Cycling Synchrotron (RCS) of CSNS to enable rapid variation of tunes, effective adjustment of Twiss parameters, and restoration of lattice superperiodicity through the machine cycle. This paper provides a detailed introduction to the design of the trim quadrupoles and preliminary results of the machine study. The beam experiments show that the trim quadrupoles play a crucial role in increasing beam power after exceeding 100 kW.

Slides TUA4C2 [4.136 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C2

About •

Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 22 October 2023

Cite •

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