Cyclotrons2013 - List of Authors (Wang, C.)

Paper

Title

Page

A Study of Multipacting Effects in Large Cyclotron Cavities by Means of Fully 3-Dimensional Simulations

142

C. Wang, B. Ji, Y. Lei, P.Z. Li, J.S. Xing, Z.G. Yin, T.J. Zhang
CIAE, Beijing, People's Republic of China
A. Adelmann, A. Gsell, M. Seidel
PSI, Villigen PSI, Switzerland

The field emission model and the secondary emission model, as well as 3D boundary geometry handling capabilities, are needed to efficiently and precisely simulate multipacting phenomena. These models have been implemented in OPAL, a parallel framework for charged particle optics in accelerator structures and beam lines. The models and their implementation are carefully benchmarked against a non-stationary multipacting theory. A dedicated multipacting experiment with nanosecond time resolution for the classic parallel plate geometry has also successfully shown the validity of OPAL model. Multipacting phenomena, in the CYCIAE-100 cyclotron, under construction at China Institute of Atomic Energy, are expected to be more severe during the RF conditioning process than in separate-sector cyclotrons. This is because the magnetic fields in the valley are stronger, which may make the impact electrons easier to reach energies that lead to larger multipacting probabilities. We report on simulation results for CYCIAE-100, which gives us an insight view of the multipacting process and help to develop cures to suppress these phenomena.

Slides TU2PB01 [7.012 MB]

TUPPT006

The Development of Radial Probe for CYCIAE-100

165

F.P. Guan, Z.G. Li, C. Wang, L.P. Wen, H.D. Xie, Z.G. Yin, T.J. Zhang
CIAE, Beijing, People's Republic of China

In the design of CYCIAE-100 beam diagnostics system, three radial probes distribute on the mid plane. These radial probes can be used for beam centering measurement. By blocking beam on five finger target and one stopping block, the radial probe can measure the radial and axial envelope of H⁻ beam at the same time. During beam commissioning, the radial probe can also be used for beam intensity measurement. The changeable probe head design makes it possible to replace the damaged part and optimization of the structure.

TUPPT026

The Design and Testing of an Automatic RF Conditioning System for the Compact Medical Cyclotron

209

Y. Lei, B. Ji, P.Z. Li, C. Wang, J.Y. Wei, Z.G. Yin, T.J. Zhang
CIAE, Beijing, People's Republic of China

The multipacting phenomenon for a compact medical cyclotron is induced by the fringing magnet field inside the accelerating structure. And it will become more interesting, when the vacuum system is equipped with diffusion pump. A method used for CYCIAE-14 cavity conditioning is reported together with the testing results of an automatic conditioning circuit designed on such basis. Apart from traditional Low Level RF control, in which close-loop regulation plays an important role, the automatic conditioning system emphasizes on the cavity startup process. It takes advantage of the modern digital signal processing technique, combined with the direct digital synthesizer to accurately limit the reflection, will condition the cavity by means of sweeping frequency, using the low RF driven power, in continuous wave mode. The electronics are designed and tested first; it will be used later in the RF system commissioning of other compact medical cyclotrons built by BRIF division of CIAE.

TUPSH002

Design and Construction of Combination Magnet for CYCIAE-100

221

S.M. Wei, Shizhong. An, M. Li, C. Wang, M. Yin, T.J. Zhang, X. Zheng
CIAE, Beijing, People's Republic of China

The high intensity compact cyclotron CYCIAE-100 being constructed at China Institue of Atomic Energy (CIAE) is designed to extract proton beam from 75MeV to 100MeV in two opposite directions by stripping foil. Two combination magnets have been designed to bend the proton beams with different energies into one common beam line. The combination magnets have been designed into the return yoke of the main magnet of CYCIAE-100 for the dynamic reason. 2 D and 3D simulation of these combination magnets has been finished, the machining of them has also been finished. The magnetic field of the combination magnets has been measured and the results show that the measurements are very closed to the calculation, indicating these two magnets can be used in the BRIF project.

Paper	Title	Page
TU2PB01	A Study of Multipacting Effects in Large Cyclotron Cavities by Means of Fully 3-Dimensional Simulations	142
	C. Wang, B. Ji, Y. Lei, P.Z. Li, J.S. Xing, Z.G. Yin, T.J. Zhang CIAE, Beijing, People's Republic of China A. Adelmann, A. Gsell, M. Seidel PSI, Villigen PSI, Switzerland
	The field emission model and the secondary emission model, as well as 3D boundary geometry handling capabilities, are needed to efficiently and precisely simulate multipacting phenomena. These models have been implemented in OPAL, a parallel framework for charged particle optics in accelerator structures and beam lines. The models and their implementation are carefully benchmarked against a non-stationary multipacting theory. A dedicated multipacting experiment with nanosecond time resolution for the classic parallel plate geometry has also successfully shown the validity of OPAL model. Multipacting phenomena, in the CYCIAE-100 cyclotron, under construction at China Institute of Atomic Energy, are expected to be more severe during the RF conditioning process than in separate-sector cyclotrons. This is because the magnetic fields in the valley are stronger, which may make the impact electrons easier to reach energies that lead to larger multipacting probabilities. We report on simulation results for CYCIAE-100, which gives us an insight view of the multipacting process and help to develop cures to suppress these phenomena.
	Slides TU2PB01 [7.012 MB]

TUPPT006	The Development of Radial Probe for CYCIAE-100	165
	F.P. Guan, Z.G. Li, C. Wang, L.P. Wen, H.D. Xie, Z.G. Yin, T.J. Zhang CIAE, Beijing, People's Republic of China
	In the design of CYCIAE-100 beam diagnostics system, three radial probes distribute on the mid plane. These radial probes can be used for beam centering measurement. By blocking beam on five finger target and one stopping block, the radial probe can measure the radial and axial envelope of H⁻ beam at the same time. During beam commissioning, the radial probe can also be used for beam intensity measurement. The changeable probe head design makes it possible to replace the damaged part and optimization of the structure.

TUPPT026	The Design and Testing of an Automatic RF Conditioning System for the Compact Medical Cyclotron	209
	Y. Lei, B. Ji, P.Z. Li, C. Wang, J.Y. Wei, Z.G. Yin, T.J. Zhang CIAE, Beijing, People's Republic of China
	The multipacting phenomenon for a compact medical cyclotron is induced by the fringing magnet field inside the accelerating structure. And it will become more interesting, when the vacuum system is equipped with diffusion pump. A method used for CYCIAE-14 cavity conditioning is reported together with the testing results of an automatic conditioning circuit designed on such basis. Apart from traditional Low Level RF control, in which close-loop regulation plays an important role, the automatic conditioning system emphasizes on the cavity startup process. It takes advantage of the modern digital signal processing technique, combined with the direct digital synthesizer to accurately limit the reflection, will condition the cavity by means of sweeping frequency, using the low RF driven power, in continuous wave mode. The electronics are designed and tested first; it will be used later in the RF system commissioning of other compact medical cyclotrons built by BRIF division of CIAE.

TUPSH002	Design and Construction of Combination Magnet for CYCIAE-100	221
	S.M. Wei, Shizhong. An, M. Li, C. Wang, M. Yin, T.J. Zhang, X. Zheng CIAE, Beijing, People's Republic of China
	The high intensity compact cyclotron CYCIAE-100 being constructed at China Institue of Atomic Energy (CIAE) is designed to extract proton beam from 75MeV to 100MeV in two opposite directions by stripping foil. Two combination magnets have been designed to bend the proton beams with different energies into one common beam line. The combination magnets have been designed into the return yoke of the main magnet of CYCIAE-100 for the dynamic reason. 2 D and 3D simulation of these combination magnets has been finished, the machining of them has also been finished. The magnetic field of the combination magnets has been measured and the results show that the measurements are very closed to the calculation, indicating these two magnets can be used in the BRIF project.