Investigation of the Temperature Effect on the Output Parameters of Radioisotope Sources of Electricity Based on Double Energy Conversion of Radiative Decay

Abstract

When developing long-life radioisotope sources of electricity for various applications (space industry, medicine, nano- and microsystem technology, cryptography, and telecommunications), an important problem lies in determining the temperature range of their reliable operation. The effect of negative and positive temperatures in the range from –60 to +60°C on the output parameters of radioisotope electricity sources based on double energy conversion is studied. It is shown that the open-circuit voltage of a radioisotope source changes four times in the indicated temperature ranges. In this case, the highest power delivered to the load is implemented at a temperature of about 0°C. The effect of temperature on all stages of energy conversion is analyzed. The investigations show that a significant decrease in the open-circuit voltage and the shape of the power-output curve are determined by two mechanisms: a decrease in the luminous intensity of radioluminescent sources of light (the temperature quenching of luminescence) and a decrease in the efficiency of photoconverters. Moreover, in the range of negative temperatures (from –60 to 0°C), the decrease in the efficiency of photoconverters is expressed only slightly, and the main contribution to the change in the output parameters of the sources is introduced by the temperature quenching of luminescence in the source of light. In the range of positive temperatures, both processes have a significant effect on reducing the output voltage and power. The developed radioisotope electrical-power sources based on double conversion can be used in electronic equipment operating at lower temperatures, for example, under Far-North conditions.