Betatrons offer advantages such as a compact structure and the absence of complex radio-frequency systems which make them well suited for industrial non-destructive testing and high-energy X-ray imaging. However, with the increasing miniaturization of betatrons, the design of the electron injection unit faces new technical challenges, and conventional electron injection schemes are no longer suitable for small-size betatrons. In this study, an electron injection unit is designed based on the operating characteristics of small-size betatrons. The proposed unit consists of a half-bridge filament drive circuit, a pulsed high-voltage circuit, and an injection current feedback circuit. The experimental results demonstrate that the optimal dose rate is achieved when the injection current is adjusted within a range of 0–1.2 A, with a nominal injection current of 0.8 A, fully satisfying the operational requirements of small-size betatrons. Compared with traditional electron injection schemes, the proposed design features a more compact circuit structure and provides an efficient and accurate solution for electron injection in electron accelerator systems.
Liu et al. (2026) studied this question.