利用GEANT4程序对复旦大学单粒子微束的毛细管准直过程进行了蒙特卡罗模拟。计算结果表明：当前采用的1 μm孔径、1 mm长度的毛细玻璃管准直器能够引出峰值能量2.2 MeV、能量分辨130 keV、束径2.4 μm的质子微束, 可达到装置对微束能量与束径分辨的设计指标, 从理论上明确了毛细管准直微束引出的可行性。针对影响入射目标细胞微束品质的主要因素, 分析了微束品质与准直系统和入射束流各状态参数的依赖关系, 为毛细管准直微束的引出与优化提供了必要的理论依据。

A GEANT4 based Monte-Carlo simulation on collimation processes of single-particle microbeam at Fudan University by capillary collimator was performed with regard to the incident beam parameters, including the divergent angle of incident beam, the incident beam energy, the misalignment angle of beam collimation and the length of collimator. As a result, a proton beam with 2.2 MeV peak energy and 130 keV FWHM which was 2.4 μm in radius, was acquired by the collimator which was 1 μm in diameter, and 1 mm in length, meeting the requirements of design. The simulation shows the possibility of acquiring microbeams in micron scale, and reveals the relationship of system design parameters and incident beam parameters with capillary-based microbeam, which determines the quality of microbeam and as it irradiates the cells.