Design Of Closed Orbit Correction Control System In Beam Accumulation Stage For HIRFL-CSRm

In an ideal storage ring,particles move along a designed reference orbit.However,the closed orbit of the particles will deviate from the reference orbit in actual situations due to the error of the magnetic field.This phenomenon is called the COD(Closed Orbit Distortion).The COD will affect beam quality,resulting in beam loss and increase the difficulty of beam tuning.In order to reduce the COD in the accumulation stage of the Lanzhou Heavy Ion Accelerator Cooling Storage Ring Main Ring(CSRm),this paper developed a COC(Closed Orbit Correction)control system.This system,which integrating response matrix measurement and closed orbit feedback,realized the closed loop correction of the beam orbit.Firstly,this paper introduced the basic situation of CSRm and the development status of accelerator control system.Then introduced the causes of COD and the basic methods for performing COC based on the beam dynamics.According to the needs of the operators,the paper summarized the specific requirements of the CSRm COC system.Then we built the overall design of the COC system on the basis of the current situation of CSRm.Under the overall design,the paper established the architecture of the hardware system and the software system.Based on the idea of modular programming,we realized multiple function modules in the service layer of the system using python.These modules contain device selection and stability test,response matrix measurement,closed orbit feedback,and closed orbit monitoring.They formed the CSRm COC service system.In addition,the paper developed a user interface for the operators with CSS(Control System Studio),which achieved the overall control of the CSRm COC system.The simulation test and the practical test results show that the system can run stably.It can perform measurement of the response matrix and correction of the beam orbit automatically.It has high availability on the CSRm,and it meets the design requirements.