Research On Penning Discharge And Transport Characteristics Of Charged Particles In Sputtering Ion Pump

Sputter ion pump,also known as Penning pump,is mainly composed of steel anode tube,titanium alloy cathode plate,ferrite permanent magnet,overload protection DC power supply and stainless steel pump body.It has the advantages of no oil,no pollution,no rotation,no vibration,simple structure and high ultimate vacuum.It has wide working range and high ultimate vacuum.It is widely used in heavy ion accelerators and scanning electron microscopes(SEM).High-end instruments such as proton heavy ion cancer medical devices and large ultra-high vacuum systems.With the development of science and technology in China,the deepening of scientific exploration and the increasing demand for technology products,the demand for high vacuum and ultra-high vacuum of various instruments and equipment has also increased,and the importance of sputter ion pumps has gradually emerged.In order to optimize the calculation method of sputtering ion pump pumping,the calculation accuracy is improved,and the charged particle transport characteristics of the discharge process are explored.Firstly,from the plasma discharge theory,the physical parameters of the Penning process in the pumping unit are simulated and combined with pumping.The simulation of the electromagnetic field distribution of the unit is used to analyze the complete discharge,sputtering,film formation and adsorption processes of the sputter ion pump pumping unit.Then,in order to determine the influence of different physical parameters on the pumping speed,combined with the theory of space gas discharge,sigmunded sputtering theory,non-normal incidence sputtering theory and space active gas adsorption theory,etc.,the parameters and pumping speed are derived.Relationship.Through the regression analysis method,it makes a two-dimensional and three-dimensional relationship diagram,which reflects the relationship between different physical quantities,and numerically formulates the physical change process in the pumping unit of the ion pump.Finally,the emission angle distribution of the working elements of the sputter ion pump was simulated by COMSOL Multiphysics plasma and electromagnetic field simulation software.According to the simulation results,several structural schemes for different vacuum degrees are proposed,namely the optimization of cathode plate structure and the optimization of charged particle transport properties.After further calculations,the two optimization methods can increase the pumping speed values of 21.05%and 30.93%,respectively.In this paper,the theoretical analysis of the pumping process of sputter ion pump is carried out,and the relationship between pumping performance and parameters is derived.Combined with the discharge sputtering process of sputter ion pump,several improved structural optimization designs are determined.It provides a theoretical basis for the design optimization of domestic sputter ion pumps.