Development of an electron gun based on CNT-cathode for traveling wave tube application

In this work, an electron gun with carbon nanotube (CNT) field emission cathode is demonstrated for traveling wave tube (TWT) application with laminar flow beam features. A maximum emission current of 9.76 mA at a bias of −11 kV is achieved by such electron gun, with current density up to 1.24 A cm−2. The output current of the electron gun can reach 8.08 mA, with the grid interception rate less than 22%. Furthermore, a Quasi-TWT with a beam tunnel of 1.6 mm is realized, which has a maximum collector current of 7.52 mA with the corresponding transmittance of 93.07%. The simulation of the beam-wave interaction implies further that our CNT field electron gun is able to meet the demands of TWT applications. •A CNT-cathode electron gun with laminar flow feature for TWT application is demonstrated.•The gun generates a current of 9.76 mA with current density up to 1.24 A cm−2.•The gun outputs a current of 8.08 mA with grid interception rate less than 22%.•A maximum collector current of 7.52 mA is achieved under certain electrode voltages together with a transmittance of 93.07%.