The electrostatic lens plays an important role in obtaining high quality focused electron/ion/slow positron beams with high spatial resolution and brightness. A novel electric lens, composed of simplified electrode structures with tube diameter gradually decreasing, is proposed for focusing charged particle beams with low energy and large spot size.

This study aims to investigate the beam dynamics of this designed electrostatic lens for validation.

Based on overall structure of electric lens focusing system, the charged particle optical simulation software SIMION was employed to optimize the parameters of this focusing system. Then combined with electron beam experiments, the key technologies involved in the electronic lens were studied in detail, including influencing factors, their distributions, and the focusing performance of the lens.

The results show that the large transverse space of the initial electron beam can be compressed effectively by arranging the electrode structure and electric potential of the lens, with focusing efficiencies exceeding 80%.

The focusing method proposed in this study has significant lateral compression advantages with wide application prospects in many focusing scenarios of different charged particle beams, such as reactor positron sources.