Calibration method of profile measurement system for laser ICF capsule

Aiming at the problem of traceability and calibration of the laser inertial confinement fusion capsule profile high-precision measurement system, proposes a calibration and traceability method based on the principle of laser differential confocal measurement. Based on the property that the zero-crossing point of the axial response curve of the laser differential confocal capsule measurement system accurately corresponds to the focus point of the measurement system, the method firstly uses the laser differential confocal capsule measurement system to measure the roundness of the standard elliptical blocks calibrated by National Institute of Metrology, China. Secondly, through comparing the roundness measurement value with the roundness metrological value of the standard elliptical blocks, the measurement transfer coefficient of the system is obtained, which is 1.03. Finally, through multiple verification measurement methods, the high-precision calibration of the system is completed. The experiment results show that using the calibrated system to conduct the comparison measurement of the laser fusion target metal capsule, the standard deviation is 37 nm; the measurement repeatability of this calibration method is 17 nm, which lays a solid foundation for the high-precision measurement of the surface profile of the capsule. © 2021, Science Press. All right reserved.