Thermal Analysis of Electron Gun for a Miniature Helix TWT

Thermal analysis of a compact miniature electron guns is essential due to the requirement of high reliability in beam performance. The electron gun for the medium power (CW) helix traveling wave tube (TWT) possesses high dimensional sensitivity due to its miniature size and the requirement of tube to tube matching with reference to their gain and phase. Keeping this in view, a detailed thermal analysis including the determination of temperature profile at various electrodes in the vicinity of cathode particularly of beam forming electrode (BFE), anode etc., and thermal drain through cathode support structure have been carried out using ANSYS package. With this package (I) a cathode support with optimum thermal drain and sufficient holding strength has been optimized and (II) thermal expansion of the electron gun electrodes have been computed in order to evaluate the inter-electrode spacings in the hot condition.