一、发展概况众所周知,当一个入射到固体表面的电子的能量给予其它电子时,某些受能电子将具有超过材料功函数的能量。若这些电子是向表面反射的,则可离开材料表面,称之为二次电子。如果二次电子的数目大于入射电,子的数目,并且这个过程连续反复进行下 First, the development of It is well known that when an electron incident on a solid surface of the energy given to other electrons, some of the electron will have energy in excess of the work function of the material. If these electrons are reflected to the surface, they can leave the surface of the material, called secondary electrons. If the number of secondary electrons is greater than the number of incident electrons, the number of sub-processes is continuously repeated