Cathode emission materials for ultra-high pressure discharge lamps

Ultra-high-pressure discharge lamps typically operate at low voltages and draw relatively high currents, ranging from tens to hundreds of amperes. To ensure the cathode can handle such high currents and provide sufficient electron emission, it is typically constructed from thoriated tungsten or cerium tungsten rods with diameters ranging from a few to tens of millimeters. To minimize excessive operating temperatures, the electrode dimensions are increased accordingly. However, this increased electrode size makes it difficult to establish a hotspot at the electrode tip, hindering stable lamp startup. To address this issue, special measures have been implemented in the cathode manufacturing of ultra-high-pressure discharge lamps.