SAP2023 - List of Keywords (vacuum)

Paper	Title	Other Keywords	Page
MOPB010	Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance	impedance, ECR, storage-ring, coupling	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)

TUPB016	High-Fidelity Modeling and Transmission Optimization for the Beamline of HUST-PTF	proton, simulation, beam-transport, coupling	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)

TUPB033	Heating Estimation of Undulator Vacuum Chamber at S3FEL	electron, wakefield, undulator, impedance	151
	H. Yi IASF, Shenzhen, Guangdong, People’s Republic of China X.F. Wang Institute of Advanced Science Facilities, Shenzhen, People’s Republic of China X.M. Yang, W.Q. Zhang DICP, Dalian, Liaoning, People’s Republic of China
	Heating of the vacuum chambers are unavoidable when electron beams pass through the chamber channels at relativistic speeds. In the undulator vacuum chambers, such effects might lead to temperature increase of the magnets and eventually cause degradations in the FEL lasing process. Thus, in this paper, the heating of the undulator vacuum chambers at S3FEL due to wake field effects and spontaneous synchrotron radiation are estimated using an analytical approach. For the wake field effects, the contribution from finite conductivity of the vacuum chamber material and from the inner surface roughness are considered. A electron beam profile from a start-to-end simulation is used to calculate the total wake field and the induced heat. For the synchrotron radiation, a simple analytical expression is used.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB033
About •	Received ※ 05 July 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 26 September 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPB010

Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance

impedance, ECR, storage-ring, coupling

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)

TUPB016

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

proton, simulation, beam-transport, coupling

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)

TUPB033

Heating Estimation of Undulator Vacuum Chamber at S3FEL

electron, wakefield, undulator, impedance

151

H. Yi
IASF, Shenzhen, Guangdong, People’s Republic of China
X.F. Wang
Institute of Advanced Science Facilities, Shenzhen, People’s Republic of China
X.M. Yang, W.Q. Zhang
DICP, Dalian, Liaoning, People’s Republic of China

Heating of the vacuum chambers are unavoidable when electron beams pass through the chamber channels at relativistic speeds. In the undulator vacuum chambers, such effects might lead to temperature increase of the magnets and eventually cause degradations in the FEL lasing process. Thus, in this paper, the heating of the undulator vacuum chambers at S3FEL due to wake field effects and spontaneous synchrotron radiation are estimated using an analytical approach. For the wake field effects, the contribution from finite conductivity of the vacuum chamber material and from the inner surface roughness are considered. A electron beam profile from a start-to-end simulation is used to calculate the total wake field and the induced heat. For the synchrotron radiation, a simple analytical expression is used.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB033

About •

Received ※ 05 July 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 26 September 2024

Cite •

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