TY  - CONF
AU  - Li, J.
AU  - Wang, K.D.
AU  - Yan, X.Q.
AU  - Zhu, K.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - Evaluation of Field Quality for Elliptical and Curved Magnets
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - The elliptical magnetic field zone is a useful tool for beam distribution homogenization and FFAG accelerators. Additionally, strongly curved magnets are studied for their application in beam transmission and nuclear fusion. However, traditional magnetic measurements, known as field harmonics, for straight magnets are not suitable for these two kinds of special magnets. In this article, advanced multipoles are used to characterize the fields of straight magnets with elliptical apertures and 2D axisymmetric enclosed curved magnets. The article provides a detailed analysis of magnetic fields using data from FEA or Biot-Savart law. Furthermore, the article discusses methods for characterizing the field quality of unclosed curved magnets used for gantry.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 96
EP  - 98
KW  - multipole
KW  - HOM
KW  - FFAG
KW  - octupole
KW  - controls
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-TUPB008
UR  - https://jacow.org/sap2023/papers/tupb008.pdf
ER  - 

TY  - CONF
AU  - Peng, S.X.
AU  - Chen, J.E.
AU  - Cui, B.J.
AU  - Guo, Z.Y.
AU  - Jiang, Y.X.
AU  - Ma, T.H.
AU  - Wu, W.B.
AU  - Zhang, A.L.
ED  - Schaa, Volker RW
ED  - Huang, Wenhui
ED  - Yan, Xueqing
ED  - Tang, Chuanxiang
ED  - Li, Lu
TI  - New Progress of the Miniaturized Microwave Ion Source at Peking University
J2  - Proc. of SAP2023, Xichang, China, 10-12 July 2023
CY  - Xichang, China
T2  - Symposium on Accelerator Physics
T3  - 14
LA  - english
AB  - 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.
PB  - JACoW Publishing
CP  - Geneva, Switzerland
SP  - 144
EP  - 146
KW  - plasma
KW  - electron
KW  - MMI
KW  - ion-source
KW  - ECR
DA  - 2024/11
PY  - 2024
SN  - 978-3-95450-265-3
DO  - doi:10.18429/JACoW-SAP2023-TUPB027
UR  - https://jacow.org/sap2023/papers/tupb027.pdf
ER  -