Some Problems in Designing Light Sources Based on High-Frequency Electrodeless Lamps
The choice of mode of the lamp and of its design begins with the choice of the bulb dimensions. The same intensity can be achieved at different dimensions of the lamp by adjusting the gas pressure and temperature of the thermostat. To increase the longevity and reliability of the lamp and reduce the power consumed by the thermostat, it is expedient to select modes with the smallest possible power in the discharge, with higher gas pressure, and with possible lower temperature of the lamp. Thus the thermostat temperature should be chosen to provide the highest intensity of radiation for a given discharge power. From Figure 9.1 it is seen that the highest density of radiation of rubidium resonance lines is about 10–25 mW/cm2 in the H-discharge mode. When a power of about 1–10 mW/cm3 is required, it is expedient to use a lamp of dimensions necessary to obtain the required optical power using the E-discharge mode. In specific experimental conditions, the lamp dimensions are chosen so that the power consumed in heating the tested objects should be at a reasonable level. For example, to obtain a rather low power (0.50 mW) an E-discharge of 0.4 W, possessing the highest integrated optical density (2–5 mW/cm2) can be used. For a reduction in light source dimensions it is possible to reduce the size of the lamp with little increase in oscillator power and thermostat temperature in order to conserve the light flux. For the E-discharge mode a reduction in the size of a spherical lamp is possible down to 8 mm diameter.
KeywordsLight Source Environmental Temperature Heat Carrier Discharge Power Voltage Stabilizer
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