Background : The DC high-voltage electron gun used in the Dalian Advanced Light Source generates electron beams with high repetition frequency, with key structural components including the cathode and anode. Physicists have imposed a stringent requirement of less than 0.1 mm for the coaxiality of these two components.

Purpose Based on the error specifications, we allocated the accuracy for calibration and installation and conducted related research.

Methods : During the calibration process, we used an articulated arm to scan data from the cathode and anode. Since the software data processing method did not meet the design requirements, we proposed a robust cylinder fitting method to determine the axial direction of the cylinder, reducing the impact of gross errors. During the installation process, we established a control network using a laser tracker to ensure that the deviation between the actual and theoretical positions of the targets met the design requirements, and this was verified.

Results : The proposed cylinder fitting method effectively eliminated the influence of gross errors, achieving a calibration error of less than 0.04 mm. During installation, error accumulation was strictly controlled, with a cumulative error of less than 0.08 mm, resulting in the high-precision completion of the entire electron gun installation project. The electron gun successfully generated an electron beam that met the physical requirements, demonstrating the effectiveness of error control during the installation process.

Conclusions : Our approach effectively controlled the magnitude of errors at each step, providing a quantifiable measurement solution for the ultra-precision assembly of other devices.