HOLLOW-CATHODE DISCHARGE DEVICE

摘要

PURPOSE:To reduce the power consumption and to lengthen the service life by constructing the starting electrode with a board having small hole from one open end of a hollow cathode and facing in the proximity of said opening and a tubular member surrounding the cathode. CONSTITUTION:A heater 22 for heating a cathode 21 is provided on the outer circumference of a cathode 21 formed with a thermion emitting material. A starting electrode 26 is fixed through a circular insulator 25 to one opening of the hollow cathode 21, where said starting electrode 26 is faced with a tubular member 27 surrounding the cathode 26 and the heater 22 at one opening of the cathode 21 and a board 28 having a small hole 28a from opening of said cathode 21 is formed integrally. The heat from the heater 22 is shielded by the tubular member 27 while the gas flow from the board 28 is limited by said board 28. Consequently the power consumption is reduced and the service life can be lengthened.