Do gas-filled switches still have a future?

Abstract

In the first part of the paper in a short review the history of the development of gas-filled high power switches is described, including all the special switching devices, which had been proposed to overcome specific shortcomings of the basic configurations of gas-filled devices like spark gaps, cold and hot cathode thyratrons and triggered vacuum tubes. The second part treats in detail the most serious problem for gas-filled switches to be still competitive with solid-state switches: Lifetime limitation by electrode erosion. The pseudospark discharge as low-pressure cold cathode device is chosen to illustrate the most important mechanisms, which contribute to electrode erosion or are related to cathode emission processes in general. As next subject of the manuscript some promising new developments in the area of gas-filled switches are described. Those obviously show that there is still a variety of applications for them, which guarantee a bright future. Based upon the results of the previous part in the last part, the pros and cons are summarized with the goal to comment the on-going process of substitution or not-substitution of gas-filled switches by solid-state devices. Finally the physical and technological limits are listed together with an outlook to future chances with the development of both types of high power switches.