匀速运动的带电粒子在穿过具有不同介电常数的两种媒质界面时要产生所谓光学渡越辐射。该辐射在粒子的入射平面上呈偏振行为；从辐射强度的角分布可以确定入射粒子的能量。在入射到双膜系统的情况下，由于干涉的发生，在第二膜前表面的强度角分布有振荡行为。利用这些现象，可对脉冲电子束包络半径、束电流密度的横向分布，束能量以及横向散角进行测量，依照这一原理在各LIA加速器上进行的脉冲电子束参数测量，获得的有效数据极大地提高了加速器的调试效率。

The so called optical-transition radiation(OTR) occurs when the charged particles with constant speed pass through interface of two media with different dielectric coefficient. The radiation shows polarization behavior while the charged particle arrives at the incidence plane, the energy of the incidence particle can be determined according to the OTR angle distribution patterns. The OTR angle distribution oscillates at the second foil’s surface due to the interference while the electron beam is entering a double foil system. Thus parameters of the pulse electron beam can be measured by using these phenomena. The parameters include electron beam envelope radius, transversal distribution of electron beam current density, electron beam energy, and electron beam’s transverse divergence. This theory is used to measure parameters of pulsed electron beam on a series of Dragon linear induction electron accelerators(LIAs) and obtain valid time-resolved results. This measurement ability has improved greatly the debugging efficiency of the Dragon LIAs.