Electron Beam Focusing Accuracy of High-Voltage Power Supplies in Electron Beam Systems

In an electron beam system, the electron beam focusing accuracy is a key indicator that determines the system performance and application effect. As the core power supply component of the electron beam system, the high-voltage power supply has a crucial impact on the electron beam focusing accuracy. In-depth exploration of the relationship between the high-voltage power supply and the electron beam focusing accuracy is of great significance for optimizing the electron beam system and enhancing its application efficiency in many fields such as material processing, electron microscopy, and lithography.
The principle of electron beam focusing is based on the action of an electric field on electrons. The high-voltage power supply establishes a strong electric field between the electron gun and the focusing electrode. After electrons are emitted from the electron gun, they are accelerated and move in the target direction under the action of the electric field force. Through a carefully designed focusing electrode structure and an appropriate electric field distribution, the electron beam can be converged to a very small focal point to achieve high-precision focusing. In this process, the output characteristics of the high-voltage power supply directly determine the stability and uniformity of the electric field, and thus affect the electron beam focusing accuracy.
The stability of the output voltage of the high-voltage power supply is the primary factor affecting the electron beam focusing accuracy. If there are voltage fluctuations, even extremely small changes, the initial velocity of electrons emitted from the electron gun will change. Electrons with different initial velocities have different trajectories in the electric field, causing the electron beam to disperse during the focusing process and unable to accurately converge to the predetermined focal point, resulting in a decrease in focusing accuracy. For example, in electron beam welding, insufficient focusing accuracy may lead to problems such as inconsistent weld width and unstable welding strength, seriously affecting the welding quality.
Secondly, the uniformity of the electric field generated by the high-voltage power supply is also crucial for the electron beam focusing accuracy. Ideally, the electric field in the focusing area should be uniformly distributed, so that all electrons in the electron beam can be affected by the same electric field force and be focused along the same trajectory. However, in practice, due to factors such as limitations in electrode manufacturing processes and non-idealities in the internal circuits of the power supply, there may be non-uniform areas in the electric field. In these areas, electrons are affected by different electric field forces, and the movement direction of the electron beam deviates, affecting the focusing accuracy. Taking an electron microscope as an example, non-uniform electric fields can cause aberrations in imaging, reducing image resolution and affecting the observation and analysis of microstructures.
In addition, the ripple of the high-voltage power supply, that is, the alternating current component superimposed on the DC output voltage, is also a factor that cannot be ignored. The ripple will introduce high-frequency interference in the electric field, causing additional disturbances to the electrons during their movement, exacerbating the divergence of the electron beam, and further reducing the focusing accuracy. Especially in application scenarios with extremely high requirements for focusing accuracy, such as nano-lithography technology, the presence of ripple may lead to deviations in lithography patterns, failing to meet the high-precision manufacturing requirements.
The performance of the high-voltage power supply in an electron beam system, including aspects such as voltage stability, electric field uniformity, and ripple control, is closely related to the electron beam focusing accuracy. By continuously optimizing the design of the high-voltage power supply and improving its performance indicators, the electron beam focusing accuracy can be effectively improved, providing a solid guarantee for the efficient application of the electron beam system in various fields.