长脉冲相对论速调管中束流脉冲缩短的研究

介绍L波段长脉冲相对论速调管放大器研究中，长脉冲强流相对论电子束(IREB)经过输入腔和中间腔间隙后的脉冲缩短问题.分析了造成束流脉冲缩短的主要机理之一是高频系统的角向非均匀模式与电子束相互作用而使得束流扩散形成的，并经过实验参数的调节，减轻了长脉冲IREB的脉冲缩短问题，得到了较强的基波调制电流.从长脉冲加速器引出500 kV，3.5 kA，1.3 μs的电子束，经过输入腔和两个群聚腔的调制后，得到了2.0 kA的基波调制电流，束流脉冲宽度由0.3 μs增加到1 μs，束流脉冲缩短问题得到明显减轻. 关键词： 相对论速调管放大器 脉冲缩短 高功率微波 长脉冲强流相对论电子束

Investigations on beam-current-pulse-shortening in a long pulse relativistic klystron amplifier

This paper presents pulse shortening of electron beams drifting through the input cavity and the idler cavity on an L-band long pulse relativistic klystron amplifier. We investigate one of the main mechanism of beam-current-pulse-shortening in which the interaction of asymmetric modes of cavity and the beams leads to the beams' expansion. Selective damping to suppress the asymmetric modes is described. The problem of beam-current-pulse-shortening through the idler cavity gap is removed to a certain extent after parameter adjustment of the input microwave and the idler cavity. In the experiment, the 446 kV,3.0 kA，1.3 μs hollow electron beams generated about 2.0 kA modulated current after two idler-cavity gaps, the width of electron beams' pulse is increased from 0.3 μs to 1.0 μs.