Indirect measurement of temperature of a coated particle cathode of spherical geometry

The retarding field method of temperature measurement was applied to a coated particle cathode of spherical geometry. Temperatures 1.5 percent above thermocouple values were obtained with a precision of about 3° C over the range of 550° to 950° C. The presence or absence of a magnetic field had no discernable effect on the results. Leakage current was corrected for and a compensation for zero potential gradient effects was made. The method was the only feasible way of measuring temperature in the specific tube under study, and provided insight for problem solution.