PAC2013 - List of Authors (Zheng, Z.)

Paper	Title	Page
WEPAC03	Electro-Magnetic Optimization and Analysis of a Quarter Wave Resonator	790
	Z. Zheng, Z.Q. He TUB, Beijing, People's Republic of China A. Facco INFN/LNL, Legnaro (PD), Italy A. Facco, Z.Q. He, Z. Liu, J. Wei, Y. Xu, Y. Zhang, Z. Zheng FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 A β=0.085 quarter wave resonator (QWR) with resonant frequency=80.5 MHz is used in the Facility of Rare Isotope Beam (FRIB). Its baseline structure is designed to achieve the FRIB specifications with optimum cost to performance ratio. Electro-magnetic optimization is introduced in this paper to modify its internal geometry to reach instead maximum accelerating gradient, while preserving the original flange to flange length. Reduced peak magnetic field and increased shunt impedance are well achieved in the optimization while keeping the same stored energy. The maximum accelerating voltage is raised accordingly. Multipacting and steering are also analyzed for the optimized cavity. This resonator could be used in the ReA linac at MSU and in all applications where the maximum accelerating voltage should be achieved in a limited space, or where the accelerator cost is mainly driven by the resonator gradient.

THPMA02	Study of Microphonics Compensation for SRF Cavity	1355
	Z. Zheng TUB, Beijing, People's Republic of China Z. Liu, D. Morris, J. Wei, Y. Zhang, S. Zhao FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 Microphonics and Lorentz Force detune the resonance frequency of a SRF cavity, leading to perturbations of the amplitude and phase of its accelerating field. Although this disturbance could be compensated by a piezo-electric tuner or with additional RF power, these two methods have conflicts, which is observed as unstable RF fields in a recent experiment. These conflicts could be explained by a model. Further experiments on ReA3 [1] cryomodule validates a conflict suggested by the model. Overall optimization of control algorithm is still needed to effectively combine the two methods.

Paper

Title

Page

Electro-Magnetic Optimization and Analysis of a Quarter Wave Resonator

790

Z. Zheng, Z.Q. He
TUB, Beijing, People's Republic of China
A. Facco
INFN/LNL, Legnaro (PD), Italy
A. Facco, Z.Q. He, Z. Liu, J. Wei, Y. Xu, Y. Zhang, Z. Zheng
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
A β=0.085 quarter wave resonator (QWR) with resonant frequency=80.5 MHz is used in the Facility of Rare Isotope Beam (FRIB). Its baseline structure is designed to achieve the FRIB specifications with optimum cost to performance ratio. Electro-magnetic optimization is introduced in this paper to modify its internal geometry to reach instead maximum accelerating gradient, while preserving the original flange to flange length. Reduced peak magnetic field and increased shunt impedance are well achieved in the optimization while keeping the same stored energy. The maximum accelerating voltage is raised accordingly. Multipacting and steering are also analyzed for the optimized cavity. This resonator could be used in the ReA linac at MSU and in all applications where the maximum accelerating voltage should be achieved in a limited space, or where the accelerator cost is mainly driven by the resonator gradient.

THPMA02

Study of Microphonics Compensation for SRF Cavity

1355

Z. Zheng
TUB, Beijing, People's Republic of China
Z. Liu, D. Morris, J. Wei, Y. Zhang, S. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
Microphonics and Lorentz Force detune the resonance frequency of a SRF cavity, leading to perturbations of the amplitude and phase of its accelerating field. Although this disturbance could be compensated by a piezo-electric tuner or with additional RF power, these two methods have conflicts, which is observed as unstable RF fields in a recent experiment. These conflicts could be explained by a model. Further experiments on ReA3 [1] cryomodule validates a conflict suggested by the model. Overall optimization of control algorithm is still needed to effectively combine the two methods.