Plasma Simulation And Structural Improvement For Kaufman Ion Source

After past half century of development, Kaufman ion source has evolved into a variety of structures, it is widely used in material modification technology for its simple structure and wide range of adjustable operating parameters. In actual production, Kaufman ion source has following problems:the ion source that has simple structure can not guarantee its uniformity, but the ion source that can guarantee its ion beam’s uniformity has a very complicated structure and difficult to maintain; In addition, the temperature of the filament during the ion source’s work period is very high, the heat generated by filament makes magnets reach the Curie point in a relatively short period of time, magnetic flux density is dropped significantly. This makes the discharge become very unstable and Working time difficult to guarantee. The ion source has Poor thermal stability.To solve the above problem, this paper aims to explore a ion source that has simple structure and good beam uniformity, and with consideration of thermal stability.Firstly, we used the DC discharge plasma module, the permanent magnetic module and external circuit module in the COMSOL Multiphysics to simulate the Kaufman ion source’s plasma, and the simulation results matches with the classical theory and experimental, this proved that the rationality of using COMSOL Multiphysics to simulate the ion source.By comparing simulate several ion source discharge chamber structure, we got the following conclusions:with the negative voltage that plate relative anode increases, the ion beam increases. But the ion density at the plate reaches the maximum when potential difference between the plate and anode is about45V, and we can use this to improve the low-energy beam characteristics of the ion source; The ideal magnetic field distribution is that the magnetic field only exists near the anode’s inner surface and the magnetic line is parallel to the anode’s surface; Shen Tech φ30Kaufman ion source structure forms the basis of improvement, we proposed two improved programs. The second option is a simple structure, and magnetic field be tied to the inner surface of the anode successfully, the resulting magnetic field distribution is similar with vane ion source’s magnetic field. Therefore, this plan theoretically has a better uniformity and can meet the requirements.