7MeV注入剥离膜系统设计

设计了一台注入能量为7 MeV的快循环同步加速器剥离膜装置，介绍了主体结构设计及高精度换膜运动结构，实现膜片精确定位及在线换膜功能。针对注入参数对膜片开展分析计算，分析了7 MeV的负氢离子束注入时相应的碳膜材料的反应截面及不同厚度的剥离效率，给出了膜片厚度的参数选择。对所设计膜片的温升和寿命进行分析，膜片的温升最高点达到755 K，远小于同类的加速器的剥离膜温度，具有更高的寿命和可靠性。

Design of the stripper foil system at a 7 MeV injection

A rapid cycling synchrotron (RCS) with a 7 MeV linac has been under construction. The negative hydrogen ion beam H- beam injected into RCS adopts the multi-turn charge exchange injection scheme. The stripper foil system which is able to replace detective foils and adjust foil position accurately in vacuum is needed. This paper presents a foil exchange system based on steel belt transmission for its high accuracy and stability. By calculating cross section, we can estimate the stripping efficiency according to particle kinetic energy and give appropriate foil thickness. Foil temperature rise and stress which are the main reasons leading to foil rupture are analyzed using finite element method and the lifetime model is combined with experiments to predict foil lifetime of our program. The stripping efficiency reaches 99.0% when the foil thickness is 40 nm. The maximum temperature point of the foil is 755.5 K. In conclusion, the mechanical system and foil property satisfy the project requirement.