OPTICAL PYROMETER MEASUREMENT OF RF POWER.
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
Pagination or Media Count:
The power output of an RF generator coupled to a graphite cylinder can be conveniently measured by determining the equilibrium temperature of the cylinder with an optical pyrometer and using the blackbody formula to obtain the power radiated by the cylinder. This power was found to agree closely with the generator output measured with a conventional water-cooled calorimeter. Graphite, with a resistivity of about .001 ohm, easy machinability, and good blackbody characteristics, is an excellent dummy load for studying the output of RF generators to such relatively high resistivity loads as plasmas and semiconductors. The pyrometer method has also been used to determine the coupling efficiency of a generator as a function of the ratio of load diameter to coil diameter. Efficiencies of 27, 41, 59, and 63 were found for ratios of 0.46, 0.61, 0.77, and 0.92, respectively. Author