Development Of Emission Guns For Charged Particles

Emission guns for charged particles are a generic term for electron guns and ion guns,which are widely used in condensed matter physics,life science and national defense aerospace fields.In this thesis,based on the design theory of emission guns,we independently developed sample irradiation electron gun,pulsed high performance electron gun,polishing ion gun,Penning ion gun and scanning ion gun,and completed the productization of each emission gun and successfully applied them in current scientific research.Specific research contents and results are as follows:(1)The working principle of the emission guns were researched,and the technologies such as particle emitting structure design,focusing lens design,deflector design and aberration optimization were solved.By analyzing the emission and control techniques,the performance influence of different structural designs is obtained to provide a basis for the design of the emission guns.(2)The design,optimization and performance evaluation of the electron optical systems of the five emission guns were carried out with the help of simulation software.The research highlights and conclusions are: a.Sample irradiation electron gun adopts a new cathode structure.The dimensional parameters of the electrostatic lens are studied to make it meet the performance requirements,and finding that lens parameters are the main influencing factor when the electron energy is low.b.Pulsed high performance electron gun adopts a double anode structure.The focusing performance is optimized by the study of the first anode size parameter,and the aberration is optimized by the study of the voltage distribution of the deflector.c.To avoid vacuum discharge,polishing ion gun has large distances between single lenses.The loss of beam current is reduced by the study of single lens parameters.d.Penning ion gun researches the influence of the addition of submerged lens on the focusing performance.e.Scanning ion gun adopts a two-stage focusing structure.The focusing performance is optimized by the study of the primary lens and the aberration is optimized by the study of the voltage distribution of the deflector.(3)The overall structural design of the emission guns was carried out by selecting the optimal parameters and engineering implementation.Based on the consideration of vacuum conditions,emission stability and vacuum discharge,the overall structure design,parts machining,parts processing,assembly and inspection of the emission guns were completed successively to realize the materialization of the emission guns.(4)The performance of various emission guns was tested and the results showed that: a.Sample irradiation electron gun’s energy is up to 5ke V,electron beam current is up to 20.8μA,and beam spot diameter is adjustable between 30-50 mm.b.Polishing ion gun’s energy up is to 20 ke V,beam current is up to 50μA.c.Penning ion gun’s ion beam current is up to 33μA,beam spot size of 12 mm.d.Scanning ion gun ion’s beam current is up to 3μA,beam spot size of 12 mm.Scanning ion gun with ion beam current up to 3μA,beam spot size is adjustable between 7-12 mm,and deflection angle is up to 4.6°.The various independently designed emission guns were evaluated to be able to satisfy the requirements of different applications,and performance compared to the existing emission guns is improved.The independent research and development of charged particle emission guns are suitable for ultra-high vacuum environments and successfully replaced foreign imported products.These results enhance the comprehensive level of our country in the field of emission guns for charged particles and promote the development of condensed matter physics,semiconductor industry,life science and national defense aerospace.