Study on formation of thin cylinder diffraction pattern

To improve the measurement accuracy of thin cylinder diameter by laser diffraction, the formation of actual diffraction pattern of thin cylinder is studied systematically. The difference between ideal diffraction pattern and that of actual measurement is considered and the actual diffraction pattern is studied on four aspects, such as white noise, characteristic of Gauss beam of LD, spatial position and disturbance of thin cylinder and focal spot. The influence to actual diffraction pattern of all the influencing factors is studied in detail and the corresponding simulation of every influencing factor is also done. Then the simulations are compared with the actual diffraction pattern and they prove that the study is right.