SAP2023 - List of Keywords (ECR)

Paper	Title	Other Keywords	Page
MOPB010	Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance	impedance, vacuum, 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)

TUPB027	New Progress of the Miniaturized Microwave Ion Source at Peking University	plasma, electron, MMI, ion-source	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

MOPB010

Impact of NEG Coating Thickness and Resistivity on Beam Coupling Impedance

impedance, vacuum, 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)

TUPB027

New Progress of the Miniaturized Microwave Ion Source at Peking University

plasma, electron, MMI, ion-source

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)