Microthermocouple for Soft Tissue Temperature Determination

Platinum-tellurium microthermocouples with a sensing junction of approximately 1.0 ¿m were constructed by vapor depositing tellurium on the exposed conical tip of a glass insulated platinum wire. The thermoelectric power, linearity, and hysteresis of the microthermocouples were determined by comparing the output of the microthermocouple with that of an iron-constantan macrothermocouple. The microthermocouple response was linear and exhibited no hysteresis over the temperature range 27-100°C. Thermoelectric power was typically 300 ¿V/°C. Typical impedance was several hundred M¿. The response time was less than 50 ms.