Electrode for discharge tube, and discharge tube using it

摘要

A discharge tube is comprised of a glass bulb, a cathode, and an anode. The cathode consists of a cathode tip portion of a bullet shape made by impregnating porous tungsten with barium, and a cylindrical lead rod of molybdenum having a recess. Apart of a base of the cathode tip portion is placed in the recess of the lead rod and a clearance between the internal surface of the recess of the lead rod and the side face of the insert part of the cathode tip portion is sealed with a molybdenum-ruthenium brazing filler metal.