Abstract
The cathode spot is easily formed where the mercury is adjacent to the surface of glass plate contaminated with sputtered materials. Utilizing this fact, we developed such a new cold mercury cathode for pulsed arc discharge lamps that enables glow-to-arc transition to occur so quickly that current of several ten amperes can flow within several μs after each pulse voltage below 1kV is applied. The cathodes of different structures are tested in order to examine the stability and longevity of arc spots and the delay time with which glow-to-arc transition takes place. It is found that the cathode structure involving a piece of glass on the metal plate is of best performance.
