3D structure of box-and-grid electron multiplier with higher electron collection efficiency

In this paper, the electron collection efficiency of dynodes in different electron multiplier (EM) structures is analyzed using Computer Simulation Technology. Three main factors that lead to low efficiency in electronic collection have been identified as crossing, trapped, and blocked electrons. The proportions of these three types of electrons are investigated to illustrate the characteristics of EMs with different structures. It is observed that the optimized 3D structure outperforms all 2D structures, and the reasons for this improvement are also discussed. The spiral EM is designed to achieve an average collection efficiency of 98.9% at the optimal parameters. By adopting the proposed structure, not only the size of the EM can be reduced, but also the gain of the EM can be significantly improved. Consequently, this will allow for a reduction in the operating voltage of the EM and prolong its lifetime.