
3.4 High-Pressure Discharge Lamps 89
spectrum, but special attention is required because of the very high pressure and
ultraviolet radiation that is emitted, which penetrates the quartz without loss of
intensity. The lamps are of low luminous efcacy, but are used wherever white
light is wanted to simulate daylight.
Several sizes of this lamp are available on the market—they are divided into
small and large xenon arc tubes ranging in power from a few watts to many
kilowatts. The term arc refers to high-pressure discharges that are due to the
exact shape given to the plasma by the thermal buoyancy. The lamps have a high
luminous ux, which rea ...