SAP2023 - List of Keywords (MMI)

Paper	Title	Other Keywords	Page
TUPB015	Research on First Harmonic Shimming Method of Cyclotron Based on Least Norm Square Solution	cyclotron, simulation, proton, software	114
	J.R. Lu, S. An, T.J. Bian CIAE, Beijing, People’s Republic of China
	The magnetic field measurement of cyclotron and the shimming of isochronous magnetic field are one of the important links in cyclotron. Due to the influence of factors such as processing errors, installation errors, and inhomogeneity of the magnetic properties of mag-net materials, the main magnetic field of the cyclotron will usually deviate from the required isochronous magnetic field and contain a certain amplitude of the first harmonic magnetic field. The existence of the first harmonic magnetic field will rapidly increase the transverse oscillation amplitude and cyclic emittance of the particles, eventually causing beam loss. In order to improve the beam quality of the cyclotron, the shimming technology of the first harmonic magnetic field is essential. In this paper, through the finite element simulation calculation of the main magnet of the cyclotron, a quantitative algorithm for the first harmonic shimming based on the least norm square solution is proposed. At present, this method is being pre-pared for apply to the magnetic field shimming of the 10MeV high-current proton cyclotron of the CIAE.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB015
About •	Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 18 September 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB027	New Progress of the Miniaturized Microwave Ion Source at Peking University	plasma, electron, ion-source, ECR	144
	S.X. Peng, J.E. Chen, B.J. Cui, Z.Y. Guo, Y.X. Jiang, T.H. Ma, W.B. Wu PKU, Beijing, People’s Republic of China A.L. Zhang USTC, Hefei, Anhui, People’s Republic of China
	The generation of plasma in a microwave ion source involves confining electrons using a static magnetic field and energizing them with an electromagnetic field that transmitted into the plasma chamber. However, according to electromagnetics theory, there is always a cut-off size in circular wave guides for a given frequency. For a 2.45 GHz microwave, this dimension is 72 mm, which should theoretically prevent transmission of the microwave into the discharge chamber and no plasma can be generated. Since 2006 Peking University(PKU) has successfully developed a series of permanent magnet 2.45 GHz microwave ion sources (PKU PMECRs¿ with a discharge chamber less than 50 mm, capable of delivering tens of mA beams for accelerators. To explain this anomalous phenomenon, a hybrid discharge heating (HDH) mode that combines surface wave plasma (SWP) and electron cyclotron heating (ECH) has been proposed. This HDH mode not only successfully explains PKU PMECRs, but also predicts that the optimized inner diameter of the plasma chamber is 24 mm, which is confirmed by experiments involving different liners in the miniaturized microwave ion source.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB027
About •	Received ※ 27 June 2023 — Revised ※ 10 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 15 June 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUPB015

Research on First Harmonic Shimming Method of Cyclotron Based on Least Norm Square Solution

cyclotron, simulation, proton, software

114

J.R. Lu, S. An, T.J. Bian
CIAE, Beijing, People’s Republic of China

The magnetic field measurement of cyclotron and the shimming of isochronous magnetic field are one of the important links in cyclotron. Due to the influence of factors such as processing errors, installation errors, and inhomogeneity of the magnetic properties of mag-net materials, the main magnetic field of the cyclotron will usually deviate from the required isochronous magnetic field and contain a certain amplitude of the first harmonic magnetic field. The existence of the first harmonic magnetic field will rapidly increase the transverse oscillation amplitude and cyclic emittance of the particles, eventually causing beam loss. In order to improve the beam quality of the cyclotron, the shimming technology of the first harmonic magnetic field is essential. In this paper, through the finite element simulation calculation of the main magnet of the cyclotron, a quantitative algorithm for the first harmonic shimming based on the least norm square solution is proposed. At present, this method is being pre-pared for apply to the magnetic field shimming of the 10MeV high-current proton cyclotron of the CIAE.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB015

About •

Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 18 September 2023

Cite •

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

TUPB027

New Progress of the Miniaturized Microwave Ion Source at Peking University

plasma, electron, ion-source, ECR

144

S.X. Peng, J.E. Chen, B.J. Cui, Z.Y. Guo, Y.X. Jiang, T.H. Ma, W.B. Wu
PKU, Beijing, People’s Republic of China
A.L. Zhang
USTC, Hefei, Anhui, People’s Republic of China

The generation of plasma in a microwave ion source involves confining electrons using a static magnetic field and energizing them with an electromagnetic field that transmitted into the plasma chamber. However, according to electromagnetics theory, there is always a cut-off size in circular wave guides for a given frequency. For a 2.45 GHz microwave, this dimension is 72 mm, which should theoretically prevent transmission of the microwave into the discharge chamber and no plasma can be generated. Since 2006 Peking University(PKU) has successfully developed a series of permanent magnet 2.45 GHz microwave ion sources (PKU PMECRs¿ with a discharge chamber less than 50 mm, capable of delivering tens of mA beams for accelerators. To explain this anomalous phenomenon, a hybrid discharge heating (HDH) mode that combines surface wave plasma (SWP) and electron cyclotron heating (ECH) has been proposed. This HDH mode not only successfully explains PKU PMECRs, but also predicts that the optimized inner diameter of the plasma chamber is 24 mm, which is confirmed by experiments involving different liners in the miniaturized microwave ion source.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB027

About •

Received ※ 27 June 2023 — Revised ※ 10 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 15 June 2024

Cite •

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