Focusing Effect in Concave Cathode Model Using Computer Simulation

It is well known that carbon nanotube (CNT) is an excellent electron field emitter. Because of its merits, CNTs have been applied recently for X-ray source for imaging. In X-ray imaging, both the emission current and the spot size of the electron beam are crucial. To fulfill these, a concave cathode structure is proposed as an alternative, and the simulation results based on the trajectories of time of flight of the electron beam are presented.