Standard source for skin type clinical thermometers
A portable standard source for skin type clinical thermometers was developed at CMS for fulfilling industrial and medical demands. It contains a modified a high quality blackbody with large size opening aperture which with large heat capacity and high emissivity. The blackbody is surrounded with heaters and the walls provide good heat conduction. In addition; the horizontal type blackbody was also restricting any excessive air convection. The temperature was measured with thermistors which were calibrated according to the International Temperature Scale of 1990 (ITS-90). The blackbody was designed at two fixed temperature points (38 °C and 30 °C). The long term temperature stability of the portable blackbody for two hour at 38 °C is ±0.0007 °C and at 30 °C is ±0.0011 °C which operation ambient temperature was within (22 + 1) °C. The emissivity of the blackbody is designed at 0.95. For converging factor (k) equals to 2, the uncertainties of the whole standard blackbody system, without device-under-test (DUT), at 30 °C and 38 °C are 0.046 °C and 0.059 °C, respectively, which were also traceable to ITS-90.
A low-temperature blackbody reference source to C
A blackbody reference source has been developed and constructed using a specially designed ammonia heat pipe cavity. This is a high emissivity (0.9993) source which provides radiance temperatures in the range to with a best measurement capability of . The design and construction of this source is presented with the results of stability, temperature uniformity and intercomparison measurements.
An Oil-Bath-Based 293 K to 473 K Blackbody Source
A high temperature oil-bath-based-black-body source has been designed and constructed in the Radiometric Physics Division at the National Institute of Standards and Technology, Gaithersburg, MD. The goal of this work was to design a large aperture blackbody source with highly uniform radiance across the aperture, good temporal stability, and good reproducibility. This blackbody source operates in the 293 K to 473 K range with blackbody temperature combined standard uncertainties of 7.2 mK to 30.9 mK. The calculated emissivity of this source is 0.9997 with a standard uncertainty of 0.0003. With a 50 mm limiting aperture at the cavity entrance, the emissivity increases to 0.99996.