| 摘要 |
PURPOSE:To improve the life of a hollow cathode and ease the starting of discharge by limiting the gas flow with a penetrating hole of a starting electrode which is provided coaxially with the hollow cathode outside the periphery of it and heating the hollow cathode through discharging between both electrodes. CONSTITUTION:An end of a hollow cathode 20 which is formed by providing a thermal electron emitter 22 on the inside surface at one end of cylinder 21, and end of a starting electrode 40 which is provided coaxially outside the periphery of the cathode 20 are fixed on an insulator 30, and other ends are extended into the discharging chamber 1. The gas flow into the inside of the cathode 20 is limited with a penetrating hole 40a on the starting electrode 40, while at the same time a voltage is applied between the cathode 20 and electrode 40 to discharge, and the cathode 20 is heated to emit thermal electrons abundantly. The penetrating hole 40a is used as an orifice and the hollow cathode is heated sufficiently without using a heater, thus the wear of the orifice is reduced to improve the life of the cathode 20, while the starting of discharge can be eased. |
