To improve the vacuum environment of an L-band, giga watt-level magnetically insulated line oscillator(MILO) , an optimized pumping model was developed for the molecular movement and collision in the high-current vacuum diode chamber and the MILO tube with Monte-Carlo method. According to the three dimensional molecular distributions in MILO, a scheme of distributed pumping was proposed. In this scheme, another pump system which was close to the velvet cathode was introduced and located between the slow wave structure and antenna. Simulation predictions were verified through the experimental test carried out on Torch-01 pulser. Distributed pumping can efficiently reduce the characteristic time of pressure drop to 0. 22 times that of single pumping. Moreover, at repetitive operation of MILO, distributed pumping maintains the vacuum degree in MILO better, and for our experimental condition, it can improve the MILO's repetition rate by 5 times.%为改善一种L波段磁绝缘线振荡器(MILO)重复频率运行时的真空环境,建立了器件在分子流下的抽气模型,采用Monte-Carlo方法对阴极脉冲放气后的瞬态抽气过程进行了模拟计算,获得了不同时刻气体分子在MILO内部的3维分布情况,并据此提出了一种“分布式”抽气方案,即在MILO靠近气源的微波传输区增加一抽气单元,以缩短脉冲间隔内的抽气时间.在Torch-01调制器上开展了MILO“分布式”抽气的实验验证,结果显示,“分布式”抽气时的气压下降特征时间为单泵的0.22倍,与模拟结果基本一致；初步的重复频率测试也表明“分布式”抽气能够缩短脉冲串间隔内的抽气时间以保持器件运行时的真空水平.在所给实验条件下,从真空的角度,“分布式”抽气能够使MILO有效运行的重复频率数提升至单泵抽气时的5倍.
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