Collimation process simulation and beam quality analysis of capillary-based microbeam

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 m in radius, was acquired by the collimator which was 1 m 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.