High aspect ratio silicon field emitter arrays (FEAS) as miniaturized stable electron source for catheter-based radiotherapy

This paper presents a miniaturized electron source based on high aspect ratio silicon (Si) field emitter arrays (FEAs) intended for generating x-rays in a catheter-based radiotherapy application. The fabricated Si FEAs demonstrate stable emission currents of approximately 10 μA at an acceleration voltage of 21.7 kV for more than 15 minutes under moderate vacuum requirements. The current stability was enhanced by the introduction of a field compensation frame design for the electric field distribution and a tip conditioning procedure of the Si FEAs. The experimental results are in line with the requirement of delivering relevant doses for cancer radiotherapy.