Research On Axial Displacement Calibration And Abbe Error Compensation Technology Of Beam Analyzer

Ray beam analyzer is mainly used in the installation of large radiotherapy equipment calibration,the positioning accuracy affects the success or failure of radiotherapy directly.Currently,the beam analyzer positioning accuracy is only 0.1mm.As the growth of the medical needs,it has cannot meet the demand.Besides,the market does not have special application in the axial displacement of beam analyzer calibration equipment.In order to solve this problem,this paper reviewed the X-ray diagnosis' s treatment equipment related national standard and displacement calibration method.According to its system indexes,such as displacement measurement error,perpendicularity and abbe error,this paper designed a set of experimental plans based on optical non-contact measurement of axial displacement of beam analyzer calibration,then experimental research and analysis are carried out.The specific research contents of this paper are as follows:Firstly,this paper builds a measurement system based on laser tracker and laser interferometer.Among them,the laser tracker measurement system is used for correlation wire analyzer ionization chamber space coordinates measuring microscope stage;Laser interferometer measurement system is used to analyze the abbe error caused by the defects on the shaft and the displacement of the measured values to compensate.Secondly,this article in the anhydrous state that using laser tracker correlation harness the positioning accuracy of the analyzer were measured.Due to the influence of water and water tank wall is unknown,the article designed a small stents to will target ball of laser tracker above water tank mouth planar,measured again.Finally,The displacement values measured by laser tracker are analyzed by using Matlab software.In the abbe error compensation experiment based on laser interferometer and CCD camera,Halcon mechanized vision algorithm package based on sub-pixel precision positioning algorithm is used to measure the size of the defect size on a shaft to calculate the abbe error caused by defects and compensate it.Among them,the error of measured displacement to beam analyzer can reach 0.068 mm.The axis and its perpendicularity error is 0.287 mm.The corresponding average of perpendicularity error in the plane of the shaft is 0.357 mm.The abbe error of theposition to 350 mm on X axis measured by Laser interferometer measurement system is 0.044 mm.Finally,making compensation for the axial displacement measurements according to the abbe error of each axis.In this paper,the axis displacement value of the correlation wire analyzer has realized the accurate measurement and the measurement resolution can reach 0.001 mm.Besides,it also analyzed the influence factors to axial positioning precision of beam analyzer,thus greatly improve the ability of its practical application.It provides a reliable guarantee for the installation of radiation therapy equipment calibration and radiation effect.