【摘要】 行波管电子枪中电子发射是影响电子注质量的关键因素,阴极发射电子时的热初速会引起电子注发散、层流性变差、射程降低等现象。目前,在考虑电子热初速的发射模型中,宏电子的热初速根据电子的统计分布规律给出,但是未考虑阴极形状对宏电子发射具有约束的影响。为了避免电子枪仿真软件中宏电子的热初速发射模型因没有考虑阴极形状约束带来的计算误差,本文提出了一种在球面阴极形状约束下的宏电子热初速发射模型。在此发射模型的基础上,通过分析电子枪设计参数对热初速效应的影响,提出了一种抑制热初速效应的电子枪设计方法,使得设计与加工装配之间有更高的吻合度。更多还原

【Abstract】 The electron emission of traveling wave tube(TWT)electron gun is a key factor affecting the quality of electron beams.Electrons emitted from cathode with thermal velocity would give rise to electron beam divergence,laminar flow deterioration and transmission distance reduction.As to now,in most electron thermal velocity emission model,the thermal velocity of electrons are computed only based on statistical distribution rules,and the effect of cathode shape constraint on macro electrons is not considered.In order to avoid errors resulted from ignoring cathode shape constrain effects,this paper presents a thermal emission model considering the constraint of sphere surface on macro electrons emission.On the basis of this emission model,we propose an electron gun design method by analyzing the impact of gun parameters on thermal velocity effects.This method could effectively reduce thermal velocity effects and improve the consistency between design and assembly of TWTs.更多还原