中能重离子微束辐照装置的真空窗

Vacuum Window of Intermediate Energy Heavy-Ion Microbeam Irradiation Facility

为了辐照生物活细胞,束流须经由真空隔离窗引入大气环境中.在真空隔离窗的设计中,对结构、材料种类及其厚度的选择既要尽可能地减小束斑展宽,又要兼顾安全性.应用有限元分析软件对不同结构、不同材料的真空窗进行受力分析,模拟真空窗的形变和等效应力,运用强度理论考察候选真空窗的安全性;并运用SRIM程序模拟离子的小角散射、横向射程,计算入射离子的能量、真空窗材料及其厚度、空气层对束斑展宽的影响;最后提出真空窗适宜的结构、材料及厚度范围.

The beam must be extracted into the air through the vacuum window to irradiate the living cell.In the window design,the material and thickness must be chosen to compromise the beam spot size broadening and the window safety.The structure-static analysis on the window of different structures and materials is done with the finite element analysis method,and the deformation and the equivalent stress are simulated.The safety of these candidates is investigated using the intensity theory.In addition,the small angle scattering and the transverse range of ions are simulated using SRIM code,including all the effects on the beam spot size broadening,such as the incident ion energy, the material and the thickness of the window and the air composing.At last,the appropriate vacuum windows are presented,including the structure,material and thickness.