【摘要】 膜窗系统是重离子束流治癌装置中隔离大气和真空的重要系统。通过应力分析,选择高强度膜(Hostaphon)和加强纤维衬底(Kevlar)联合使用,既可以使束流通过,同时中子产额少,还可以承受大气压力。采用双层真空结构,消除膜材料的漏气效应,使与膜窗相连的主系统真空度达到了10-6Pa。更多还原

【Abstract】 The large-sized window of the heavy ion accelerator,dedicated to the cancer therapy terminal,was designed and constructed.The impacts of the structures and materials of the window on the characteristics of the carbon ion beam were evaluated.The window consists of the double-layered polymer sheets,secured separately on the frame of the rectangular-structured flange: the outside is a high-strength Hostaphon polymer sheet,and the inner one is a Kevlar49 reinforced faber-woven sheet.The mechanical properties of the double-layered polymer sheets were modeled and simulated in finite element method(FEM) with the software package ANSYS,to optimize the thickness and separation between the two sheets.The test results show that the window has fairly a high ion transmission coefficient and a low leak rate,and that the pressure in the main vacuum chamber can be kept to below 10-6 Pa.In addition,few neutrons were produced.更多还原