The 30mev linac can be used as energy recovery accelerator with photo - cathode rf - gun injector . and multi - cavities photo - cathode injector can not only improve the quality of output electron beam , but also decrease the effect of phase question in the energy recovery process 当注入器束流电子能量接近10mev后，第一加速段与束线中产生的减速相位与加速相位的差是小的，对能量回收效率的影响可以忽略。
Then , the beam orbit correction in bepcii lianc is simulated by optimum liar program and a design study on the optimum orbit correction system for bepcii linac is discussed . the optimum corrector ' s distribution and the required tolerances of misalignment of the linac components are given 最后用改进了的liar程序对bepc直线加速器轨道进行模拟计算，讨论了该校正系统的设计研究，并给出了轨道校正系统的优化布局和对加速器部件的安装公差的要求。
Simulation on the a - magnet of 30mev linac is also done with the gpt code ; the movement picture of electron beam in a - magnet is presented ; the change of beams emittance , the compression effect of bunch length , change of energy dissipation and achromatic angle of true a - magnet are explored . this chapter mainly introduces some characteristics and properties of the main accelerate stage in 30mev linac system 利用gpt程序对30mevlinac中的-磁铁进行了动力学模拟，给出了电子束在-磁铁中的运动图像，研究了注入器输出束流经过-磁铁后束流发射度的变化、束团长度的压缩效应、能散度的变化以及-磁铁实际的消色散入射角。
Numeric simulation is done based on 30mev linac structure and the corresponding parts " parameters . the simulate result shows that the design of beam line is reasonable . the beam properties change very small when the drifting distance before the first acceleration stage is changed in the certain ranges 根据30mevlinac结构和元件参数进行了整体的数值模拟，模拟结果表明： 30mevlinac中各个加速段的结构与性能较好，输出束流的发射度和能散度都较小，束线的设计也较合理。
Secondly , the beam orbit offset effects caused by the initial beam offset and the linac components " offsets have been quantitatively studied first . as an example with the injector linac for beijing electron positron collider upgrading project ( bepcii ) , the beam orbit offset caused by the above error effects have been simulated and analyzed 其次定量研究束流的初始径向误差和加速器部件的安装误差等对束流轨道偏轴的影响，并以北京正负电子对撞机二期工程( bepc )的直线加速器为例，给出了上述各种误差导致轨道偏轴的模拟计算结果及其分析。
