Speaker
Description
The Fixed-Field Alternating Gradient (FFA) accelerator ring of the China Spallation Neutron Source (CSNS) requires a high-reliability vacuum system to ensure efficient beam transmission and long-term operational stability. This paper presents the preliminary design of the CSNS-FFA vacuum system, which is characterized by its large scale, with an average radius of 12 meters, making it the largest among similar international FFA facilities. The system is designed to achieve an operating vacuum pressure better than 1.0×10⁻⁵ Pa. The ring is composed of 12 arc sections and 12 straight sections, with the vacuum environment primarily maintained by sixteen 600 L/s ion pumps distributed in the straight sections. Simulation results indicate that this configuration can maiThe Fixed-Field Alternating Gradient (FFA) accelerator ring of the China Spallation Neutron Source (CSNS) requires a high-reliability vacuum system to ensure efficient beam transmission and long-term operational stability. This paper presents the preliminary design of the CSNS-FFA vacuum system, which is characterized by its large scale, with an average radius of 12 meters, making it the largest among similar international FFA facilities. The system is designed to achieve an operating vacuum pressure better than 1.0×10⁻⁵ Pa. The ring is composed of 12 arc sections and 12 straight sections, with the vacuum environment primarily maintained by sixteen 600 L/s ion pumps distributed in the straight sections. Simulation results indicate that this configuration can maintain an internal pressure below 3.0×10⁻⁶ Pa.
A key component of the design is the arc vacuum chamber, which features a large size, thin walls, and a complex cross-section to accommodate the beam envelope and correction coils within the magnet gap. The chamber is constructed from 316L stainless steel. Static structural analysis was performed to optimize the chamber's wall thickness. The results show that with a wall thickness of 13 mm, the maximum deformation under atmospheric pressure is 1.97 mm, and the maximum equivalent stress is 115 MPa, both of which satisfy the mechanical strength and deformation requirements. This design ensures the structural integrity of the vacuum chamber while meeting the stringent demands of the beam physics.ntain an internal pressure below 3.0×10⁻⁶ Pa.
A key component of the design is the arc vacuum chamber, which features a large size, thin walls, and a complex cross-section to accommodate the beam envelope and correction coils within the magnet gap. The chamber is constructed from 316L stainless steel. Static structural analysis was performed to optimize the chamber's wall thickness. The results show that with a wall thickness of 13 mm, the maximum deformation under atmospheric pressure is 1.97 mm, and the maximum equivalent stress is 115 MPa, both of which satisfy the mechanical strength and deformation requirements. This design ensures the structural integrity of the vacuum chamber while meeting the stringent demands of the beam physics.