Optical Properties of Hydrogen Discharge Lamp Isoo MASUDA
1959 Volume 28 Issue 3 Pages 152-156
Details
1959 Volume 28 Issue 3 Pages 152-156
A hot cathode type hydrogen discharge lamp, operated by condenced discharge of 300 mA-30 watt, emitting a continuous spectrum in the u, v, region, has been developed. The energy distribution and the dependency of light output on the lighting time are measured and the causes of lowering the light output are discussed.
The measurement of energy distribution of the lamp is made by taking into account the dispersion and effective transmission of the monochrometer and the spectral sensitivity of the detector (a photomultiplier).
The emission intensity of continuous spectrum has its peak at about 2450Å. In the visible region of the spectrum, the emission curve shows a complex structure due to overlapping of various band spectra, while Ha (6563Å) line is markedly distinguishable from the back ground.
The ratio of the intensity of Ha line to that of the continuous spectrum increases gradually with lighting time.
The employment of fused quartz or the glass for the envelope of germicidal lamp as the material for window of the lamp is attended with some undesirable consequences such that a complex procedure of graded seal is needed or the light output of the lamp is affected by solari-zation effect.
A new sort of special glass has been prepared which shows negligibly small solarization effect, good transmitting character in the u, υ, region and thermal expansion characteristics similer to those of hard borosilicate glass.
Consequently, the variation of energy distribution of the lamp is remarkably reduced. In such a lamp, the mechanisms other than solarization effect, e. g., the decrease of hydrogen pressure due to clean-up effect and the damage of oxide cathode, may be as well responsible for the lowering of its light output.
It has been recognized that the light intensity in the u, v, region is sufficiently great even at the end of 1100 hour lighting under severe conditions, and the lamp of this type is very satisfactory as the light source for spectrophotometry in this region.
