DEVELOPMENT AND CHARACTERIZATION OF A SURFACE PROBE CALIBRATION SYSTEM AT NIS

This paper presents the development and characterization of a dedicated calibration system for surface temperature probes over the temperature range from 50 C to 300 C. The system was developed at the National Institute for Standards (NIS) to improve the traceability and reliability of surface temperature measurements.The calibration setup is based on a precision-machined aluminum plate combined with a flat spiral heater to ensure uniform heat distribution. The system performance was evaluated in terms of temperature stability, temperature in-homogeneity, and agreement with a calibrated reference thermocouple. The results demonstrate that the system achieves high stability, ranging between C and =0.2 C, while temperature in-homogeneity is limited to values between 0.2 C and 0.5 C across the investigated range.A comprehensive uncertainty analysis was carried out considering all significant sources of uncertainty. The expanded uncertainty (k = 2) was found to range from =0.3 C to =0.6 C over the operating temperature range. The developed system provides a reliable, traceable, and practical solution for surface temperature probe calibration, representing an improvement over conventional calibration method.