Research on Beam Spot Focusing Technology of High Voltage Power Supply in Electron Beam Systems

1. Physical Mechanism of Beam Focusing
In electron beam systems, the core function of high-voltage power supplies is to achieve beam spot focusing through precise control of electron beam energy distribution. When the acceleration voltage reaches 50-300kV, the electron velocity approaches the speed of light, and the space charge effect significantly affects beam quality. The focusing process essentially compensates for space charge-induced divergence by adjusting electric field distribution, forming high-energy density spots with diameters less than 1μm on the target surface.
2. Key Design Parameters of High Voltage Power Supplies
Voltage Stability: Ripple coefficient below 0.01% is required to ensure consistent electron beam energy distribution. Modern power systems use multi-stage LC filters and digital PID control to suppress voltage fluctuations to millivolt levels.
Dynamic Response Speed: For varying beam currents (e.g., pulsed operation), power supplies need microsecond-level voltage adjustment capability to maintain optimal focusing.
EMC Performance: Through shielding design and grounding optimization, stray electromagnetic field interference on electron trajectories is reduced to below 10mGauss.
3. Dynamic Focusing Control Technology
Real-time Feedback System: Faraday cups detect beam current density distribution, combined with CCD imaging to obtain spot parameters for closed-loop control.
Intelligent Algorithm Application: Neural network-based predictive models pre-compensate space charge effects, maintaining focus stability during beam current variations.
Multi-physics Coupling Optimization: COMSOL simulations analyze electric-magnetic field-space charge interactions to optimize electrode structures.
4. Application Challenges and Solutions
In high-power density applications, beam drift and energy dispersion are major technical challenges. Studies show that using high-frequency modulated power supplies (>100kHz) with dynamic magnetic lens compensation can control beam drift within 50nm. Redundant power architectures and fault prediction algorithms enhance system reliability and maintainability.
Conclusion
As a critical component of electron beam systems, high-voltage power supplies directly determine beam focusing accuracy and processing quality. Through interdisciplinary innovation, future power systems will evolve towards higher integration, lower power consumption, and intelligent control, providing key technical support for precision manufacturing, material modification, and other advanced fields.