Experimental Study on Collimation Characteristics of an ECRH System with a 28GHz/50kW Gyrotron

Abstract

In this paper, the collimation characteristics of an electron cyclotron resonance heating (ECRH) system with a 28GHz/50kW gyrotron in EXL-50 are studied experimentally. Through using laser trackers and designing matching tooling, test errors of horizontal distances and vertical distances between the transmission line and the flange center are all within 1mm, which are less than 0.4% and 0.07% respectively. In addition, online beam spot test with a 150 ms short pulse from a 28 GHz gyrotron also proves good collimation characteristics of the ECRH system. Finally, spherical plasma is formed through injecting the microwave to the vacuum chamber.