复合泵在医用重离子加速器上的应用研究

Study on combination pump used in heavy ion medical mechanism

同步加速器是医用重离子加速器的主加速部件。考虑到其设计空间紧凑的特点及其真空系统的设计要求,采用将非蒸散型吸气剂泵(NEG)组件嵌入国产溅射离子泵(SIP)空腔内组成的复合泵作为真空系统的主泵。本文测试了复合泵的抽气性能,测试并估算了复合泵的H2饱和容量和再生周期,计算了同步加速器真空系统的压力分布。测试及计算结果表明:相比于SIP,复合泵对N2的抽速提高了20%,对H2的抽速提高了70%～100%,且具有更高的极限真空度,其再生周期为2年,压力分布能够满足同步加速器真空系统的设计要求。

The combination pump combined non evaporable getter pump with sputter ion pump was chosen as the main pump. The pump was designed for the compact space of synchrotron and technical specification of its vacuum system. The pumping characteristics have been tested. The hydrogen sorption capacity and time between two reactivations have been measured and predicted. The pressure distribution of synchrotron has also been calculated. The testing results show that the pumping speed of combination pump for nitrogen and hydrogen increase 20% and 70% respectively as compared with sputter ion pump; the ultimate pressure of combination pump is also better than sputter ion pump ; and time between two reactivations of the combination pump is about 2 years. It can meet the synchrotron vacuum system requirement.