SAP2023 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOPB016	Matching Section Optics Design for the MeV Ultrafast Electron Beam Experimental Facility	electron, sextupole, dipole, simulation	37
	H. Qi, K. Fan, Z. Liu, C.-Y. Tsai, J. Wang HUST, Wuhan, People’s Republic of China
	This paper introduces the design and optimization of the matching section beamline for the ultrafast electron research platform at Huazhong University of Science and Technology (HUST). The matching section serves as a connection between the main beamline and the beam physics research beamline, aiming to achieve efficient and precise control over the electron beam trajectory and parameters. To evaluate its performance, particle tracking simulations using GPT software were conducted. When the beam is set at 3 MeV and 1 pC charge, the matching section is capable of compressing the bunch length to approximately 50 fs. This level of compression is crucial for ultrafast electron research applications, as it enables the study of phenomena that occur on extremely short time scales, demonstrating its effectiveness in achieving precise beam control and compression.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB016
About •	Received ※ 29 June 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 20 January 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB009	General Design of 180 MHz RFQ for BNCT	rfq, cavity, simulation, dipole	99
	Z.Q. Ren, Z. Li, W.L. Liao, P.T. Lin, X.B. Luo, X.J. Pu, X.M. Wan, Y.F. Yang SCU, Chengdu, People’s Republic of China
	Accelerator based boron neutron capture therapy (AB-BNCT) is a promising cancer treatment technology. An overall design have been proposed of a 180 MHz radio frequency quadrupole (RFQ) accelerator for BNCT. The particularity of dynamic design of the RFQ is that the average aperture radius changes along the accelerator. Beam dynamics design results show that the length of accelerator which accelerates protons from 35 keV to 2.81 MeV is 5.07 m, and the transmission up to 99.65%. In terms of radio frequency (RF) structure design, two shapes of cross section of cavity were simulated and compared, i.e., quadrilateral cavity and octagonal cavity. The results show that quadrilateral cavity performed better and was finally selected. Meanwhile, in order to keep the frequency of dipole mode away from the working quadrupole mode, 20 pairs of Pi-mode stabilizer rods are considered. The simulation results show that a large mode separation of more than 20MHz between the operating quadrupole mode and nearest dipole mode can be obtained, this is sufficient to deal with the errors caused by machining and misalignment.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB009
About •	Received ※ 09 July 2023 — Revised ※ 11 July 2023 — Accepted ※ 15 July 2023 — Issued ※ 24 July 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB013	Multipole Field Optimization of X-Band High Gradient Structure	multipole, cavity, simulation, acceleration	108
	B.Y. Feng, H.B. Chen, Q. Gao, X. Lin, J.R. Shi, H. Zha TUB, Beijing, People’s Republic of China
	The X-band constant gradient acceleration structure plays a crucial role in the VIGAS project. However, the presence of a multipole field component in the struc-ture’s coupler leads to an increase in ray bandwidth and a decrease in yield, ultimately affecting the quality of the generated rays. Through calculations, it has been determined that the quadrupole field component is particularly prominent in the original structure, ac-counting for 29.5% of the fundamental mode strength. Therefore, it is necessary to modify the cavity struc-ture of the coupler. By altering the shape of the cavity to two staggered circles, the objective of reducing the quadrupole field is achieved. The optimized quadru-pole field component now accounts for approximately 0.3% of the fundamental mode strength. Subsequently, the non-resonant perturbation method was employed to simulate and experimentally measure the magnitude of the multipole field component in the actual acceler-ation cavity.
	Poster TUPB013 [0.350 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB013
About •	Received ※ 30 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 27 September 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB019	Beam Dynamics in Superconducting Proton Linac	focusing, simulation, acceleration, resonance	126
	X.M. Wan, Z. Li, W.L. Liao, P.T. Lin, X.B. Luo, X.J. Pu, Z.Q. Ren, Y.F. Yang SCU, Chengdu, People’s Republic of China
	Funding: This work was supported by the National Natural Science Foundation of China (Grant Nos. 11375122 and 11875197). Beam loss control is a crucial research direction in high-current superconducting linear accelerators (SCL). The research findings include firstly, for continuous beams, when tune depression eta > 0.7, zero current periodic phase advance (σ0t) can partially exceed 90° during transport in solenoid and quadrupole doublet periodic focusing channels. Different results occur when eta < 0.7. Secondly, in the solenoid system, σ0t can partially exceed 90° without significant impact on beam quality. In the quadrupole doublet focusing system, the partial breakdown of 90° affects beam quality. Thirdly, Similar conclusions hold for acceleration effects. Fourthly, numerical analysis shows that double-period structures have more stringent design criteria than fully period structures. The double-period structure can cause envelope instability even if σ0t < 90°. Fifthly, the primary factor causing halo is the 2:1 resonance. Additionally, when eta is small, higher-order resonances can also cause halo.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB019
About •	Received ※ 09 July 2023 — Revised ※ 11 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 08 April 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPB016

Matching Section Optics Design for the MeV Ultrafast Electron Beam Experimental Facility

electron, sextupole, dipole, simulation

37

H. Qi, K. Fan, Z. Liu, C.-Y. Tsai, J. Wang
HUST, Wuhan, People’s Republic of China

This paper introduces the design and optimization of the matching section beamline for the ultrafast electron research platform at Huazhong University of Science and Technology (HUST). The matching section serves as a connection between the main beamline and the beam physics research beamline, aiming to achieve efficient and precise control over the electron beam trajectory and parameters. To evaluate its performance, particle tracking simulations using GPT software were conducted. When the beam is set at 3 MeV and 1 pC charge, the matching section is capable of compressing the bunch length to approximately 50 fs. This level of compression is crucial for ultrafast electron research applications, as it enables the study of phenomena that occur on extremely short time scales, demonstrating its effectiveness in achieving precise beam control and compression.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-MOPB016

About •

Received ※ 29 June 2023 — Revised ※ 08 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 20 January 2024

Cite •

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

TUPB009

General Design of 180 MHz RFQ for BNCT

rfq, cavity, simulation, dipole

99

Z.Q. Ren, Z. Li, W.L. Liao, P.T. Lin, X.B. Luo, X.J. Pu, X.M. Wan, Y.F. Yang
SCU, Chengdu, People’s Republic of China

Accelerator based boron neutron capture therapy (AB-BNCT) is a promising cancer treatment technology. An overall design have been proposed of a 180 MHz radio frequency quadrupole (RFQ) accelerator for BNCT. The particularity of dynamic design of the RFQ is that the average aperture radius changes along the accelerator. Beam dynamics design results show that the length of accelerator which accelerates protons from 35 keV to 2.81 MeV is 5.07 m, and the transmission up to 99.65%. In terms of radio frequency (RF) structure design, two shapes of cross section of cavity were simulated and compared, i.e., quadrilateral cavity and octagonal cavity. The results show that quadrilateral cavity performed better and was finally selected. Meanwhile, in order to keep the frequency of dipole mode away from the working quadrupole mode, 20 pairs of Pi-mode stabilizer rods are considered. The simulation results show that a large mode separation of more than 20MHz between the operating quadrupole mode and nearest dipole mode can be obtained, this is sufficient to deal with the errors caused by machining and misalignment.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB009

About •

Received ※ 09 July 2023 — Revised ※ 11 July 2023 — Accepted ※ 15 July 2023 — Issued ※ 24 July 2024

Cite •

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

TUPB013

Multipole Field Optimization of X-Band High Gradient Structure

multipole, cavity, simulation, acceleration

108

B.Y. Feng, H.B. Chen, Q. Gao, X. Lin, J.R. Shi, H. Zha
TUB, Beijing, People’s Republic of China

The X-band constant gradient acceleration structure plays a crucial role in the VIGAS project. However, the presence of a multipole field component in the struc-ture’s coupler leads to an increase in ray bandwidth and a decrease in yield, ultimately affecting the quality of the generated rays. Through calculations, it has been determined that the quadrupole field component is particularly prominent in the original structure, ac-counting for 29.5% of the fundamental mode strength. Therefore, it is necessary to modify the cavity struc-ture of the coupler. By altering the shape of the cavity to two staggered circles, the objective of reducing the quadrupole field is achieved. The optimized quadru-pole field component now accounts for approximately 0.3% of the fundamental mode strength. Subsequently, the non-resonant perturbation method was employed to simulate and experimentally measure the magnitude of the multipole field component in the actual acceler-ation cavity.

Poster TUPB013 [0.350 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB013

About •

Received ※ 30 June 2023 — Accepted ※ 11 July 2023 — Issued ※ 27 September 2024

Cite •

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

TUPB019

Beam Dynamics in Superconducting Proton Linac

focusing, simulation, acceleration, resonance

126

X.M. Wan, Z. Li, W.L. Liao, P.T. Lin, X.B. Luo, X.J. Pu, Z.Q. Ren, Y.F. Yang
SCU, Chengdu, People’s Republic of China

Funding: This work was supported by the National Natural Science Foundation of China (Grant Nos. 11375122 and 11875197).
Beam loss control is a crucial research direction in high-current superconducting linear accelerators (SCL). The research findings include firstly, for continuous beams, when tune depression eta > 0.7, zero current periodic phase advance (σ0t) can partially exceed 90° during transport in solenoid and quadrupole doublet periodic focusing channels. Different results occur when eta < 0.7. Secondly, in the solenoid system, σ0t can partially exceed 90° without significant impact on beam quality. In the quadrupole doublet focusing system, the partial breakdown of 90° affects beam quality. Thirdly, Similar conclusions hold for acceleration effects. Fourthly, numerical analysis shows that double-period structures have more stringent design criteria than fully period structures. The double-period structure can cause envelope instability even if σ0t < 90°. Fifthly, the primary factor causing halo is the 2:1 resonance. Additionally, when eta is small, higher-order resonances can also cause halo.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB019

About •

Received ※ 09 July 2023 — Revised ※ 11 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 08 April 2024

Cite •

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