HB2012 - List of Authors (Fu, S.)

Paper

Title

Page

Intense-beam Issues in CSNS and C-ADS Accelerators

25

S. Fu, S.X. Fang, Z. Li, J. Peng, J.Y. Tang, S. Wang, F. Yan
IHEP, Beijing, People's Republic of China

In 2011 construction of two intense-beam accelerators were launched for China Spallation Neutron Source (CSNS) project and China Accelerator Driven System (C-ADS) project. CSNS uses a pulsed accelerator with an H⁻ linac and a rapid cycling synchrotron, and C-ADS has a CW proton linac with superconducting cavities. In both cases, the beam power is high and beam loss control is a key issue in beam dynamics. Beam emittance growth and beam halo formation must be carefully studied in beam dynamics and well controlled in machine design. This paper will present a brief introduction to the physics design of the two intense-beam accelerators, especially on the issue of beam instability. In their linac design equapartitioning focusing scheme is adopted to avoid coupling instability. Some beam halo formation experimental results due to mismatching will be compared with simulations. Beam halo generation due to the quench of superconducting cavity and magnet is investigated in detail and compensation scheme is also proposed. Beam loss study for the error effects and orbit correction will be presented.

Slides MOI1C01 [3.747 MB]

MOP218

Dynamics of Particles in a Tilted Solenoidal Focusing Channel

97

H. Jiang, S. Fu
IHEP, Beijing, People's Republic of China

We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

TUO3B04

End to End Beam Dynamics and Design Optimization for CSNS Linac

286

J. Peng, S. Fu, H.C. Liu, H.F. Ouyang, X. Yin
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) will use a linear accelerator delivering a 15mA beam up to 80MeV for injection into a rapid cycling synchrotron (RCS). Since each section of the linac was determined individually, a global optimization based on end-to-end simulation results has refined some design choices, including the drift-tube linac (DTL) and the medium energy beam transport (MEBT). The simulation results and reasons for adjustments are presented in this paper.

Slides TUO3B04 [1.131 MB]

TUO3C05

Beam Commissioning Plan for CSNS Accelerators

334

S. Wang, S. Fu, H.F. Ouyang, J. Peng
IHEP, Beijing, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11175193)
The China Spallation Neutron Source (CSNS) is now under construction, and the beam commissioning of ion source will start from the end of 2013, and will last several years for whole accelerator. The commissioning plan for CSNS accelerators will be presented in the presentation, including the commissioning correlated parameters, the goal at different commissioning stages and some key commissioning procedures for each part of accelerators. The detailed schedule for commissioning will be also given.

Slides TUO3C05 [3.574 MB]

Paper	Title	Page
MOI1C01	Intense-beam Issues in CSNS and C-ADS Accelerators	25
	S. Fu, S.X. Fang, Z. Li, J. Peng, J.Y. Tang, S. Wang, F. Yan IHEP, Beijing, People's Republic of China
	In 2011 construction of two intense-beam accelerators were launched for China Spallation Neutron Source (CSNS) project and China Accelerator Driven System (C-ADS) project. CSNS uses a pulsed accelerator with an H⁻ linac and a rapid cycling synchrotron, and C-ADS has a CW proton linac with superconducting cavities. In both cases, the beam power is high and beam loss control is a key issue in beam dynamics. Beam emittance growth and beam halo formation must be carefully studied in beam dynamics and well controlled in machine design. This paper will present a brief introduction to the physics design of the two intense-beam accelerators, especially on the issue of beam instability. In their linac design equapartitioning focusing scheme is adopted to avoid coupling instability. Some beam halo formation experimental results due to mismatching will be compared with simulations. Beam halo generation due to the quench of superconducting cavity and magnet is investigated in detail and compensation scheme is also proposed. Beam loss study for the error effects and orbit correction will be presented.
	Slides MOI1C01 [3.747 MB]

MOP218	Dynamics of Particles in a Tilted Solenoidal Focusing Channel	97
	H. Jiang, S. Fu IHEP, Beijing, People's Republic of China
	We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

TUO3B04	End to End Beam Dynamics and Design Optimization for CSNS Linac	286
	J. Peng, S. Fu, H.C. Liu, H.F. Ouyang, X. Yin IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) will use a linear accelerator delivering a 15mA beam up to 80MeV for injection into a rapid cycling synchrotron (RCS). Since each section of the linac was determined individually, a global optimization based on end-to-end simulation results has refined some design choices, including the drift-tube linac (DTL) and the medium energy beam transport (MEBT). The simulation results and reasons for adjustments are presented in this paper.
	Slides TUO3B04 [1.131 MB]

TUO3C05	Beam Commissioning Plan for CSNS Accelerators	334
	S. Wang, S. Fu, H.F. Ouyang, J. Peng IHEP, Beijing, People's Republic of China
	Funding: Supported by National Natural Science Foundation of China (11175193) The China Spallation Neutron Source (CSNS) is now under construction, and the beam commissioning of ion source will start from the end of 2013, and will last several years for whole accelerator. The commissioning plan for CSNS accelerators will be presented in the presentation, including the commissioning correlated parameters, the goal at different commissioning stages and some key commissioning procedures for each part of accelerators. The detailed schedule for commissioning will be also given.
	Slides TUO3C05 [3.574 MB]