Abstract
Emission characteristics of mercury lamps were measured in the spectral range from 50 to 800μ with a far infrared spectrometer. The lamps measured are those of quartz envelope with presumed mercury vapor pressure of several atmospheric pressures.
The ratio of the intensity of radiation from the mercury vapor to that from the tube walls is determined by measuring the intensity of radiation after abrupt switching-off of the discharge current. In the spectral range around 50μ, most of the radiation is emitted from the heated tube walls while, above 300μ, more than 80 percent of the radiation comes from the mercury vapor.
Relative intensity of the radiation was measured for an input power of 25_??_220 W/cm. It is found that, above 300μ and above a certain input power, further increase of the power does not apprecially cause the radiation intensity to increase.
The radial intensity distribution was measured in the visible and far infrared regions. The distribution for the far infrared region is considerably broader than that in the visible region.
Observed and calculated results in its general trend if self-absorption in the plasma of high pressure vapor is assumed.
