3D-Printed Plasma Cathode Electron Source for Educational Purposes

In secondary education, cathode-ray tubes (CRTs) are often the first choice when it comes to investigating the behavior of electrically charged particles in electric and magnetic fields. While CRTs offer some advantages, mainly from a practical point of view, they are on the whole ill-suited for an inquiry-based approach since they provide very limited room for modification or hands-on experimentation. Therefore, a 3D-printable plasma electron gun has been developed, which is at the same time modular, inexpensive, and easily accessible. The main objective is to provide teachers and students with an easy-to-operate electron beam source that allows conducting experiments on beam generation, beam focusing, and beam deflection as a hands-on activity in a classroom setting. From a technical point of view, this can be achieved by substituting the hot cathode as standard electron source by a plasma cathode electron gun, which can be operated at fore-vacuum pressure and in reactive gases. We provide a proof of concept that a low-cost 3D-printed plasma electron source is feasible and that beam generation can be accomplished.