Measurement of Finite Radius of the Virtual Source for Practical Field Emission Gun
Yang Deqing Chen Ergang(Department of Physics,Yunnan University,Kunming 650091)
This paper puts forward a new method of measuring finite radius of the virtual source for practical field emission gun (FEG) on basis of analysing the factors and effecting finite radius of the virtual source. The method is called field-electron microscope method (FEM). Finite radius of the virtual source in practical FEG measured by using the method and the results shown:measured value is well consistent with the calculated value of the theory for spheroidal-cone model. The fact shows that the method is not only simple but also effective to the measurement of finite radius of the virtual source for FEG. It has higher practical value.