The Characterization Of Cesium, Sodium Heat Pipe Blackbody Radiation Sources And The Research Of Calibration Methods

As a kind of thermometry technology, radiation thermometry is widely used. It has a lot of the characteristics, such as high sensitivity, fast response, good dynamic response, remote automatic thermometry and so on. Blackbody radiation theory is the theoretical basis of radiation thermometry. The improvement of the blackbody radiation technical level is metrology technical foundation of the radiation thermometry. The radiation characteristics of blackbody depend on its temperature and spectral emissivity. The higher spectral emissivity, the closer of the ideal blackbody radiation characteristics, this means that the high absorption rate of blackbody radiation, the radiation temperation of blackbody is less affected by environmental radiation. Using as a standard radiation source, its uncertainty is smaller. With the development of radiation thermometry technology, the test and calibration requirements of radiation thermometer are increasing, and the demanding is improving. As a standard device, the blackbody radiation sources are widely used in the calibration of radiation thermometers. Effective traceability and evaluation of its radiation characteristics guarantee the accurate and uniform of radiation temperature measurement. At present, most of the blackbody radiation sources can only achieve its removable contact thermometer traceability, they are needed to develop high emissivity blackbody radiation standards for all areas to provide the highest standards traceable in our country.The paper describes the manufacture of blackbody radiation sources (270～1000)℃at National Institute of Metrology of China. In this paper, the composition, performance evaluation, calibration repeatability, emissivity wavelength selectivity and calibration methods of the system are introduced, and the uncertainty level of each heat pipe is analysed.The research contents are as follows:1) The characteristics of (270～1000)℃Cesium, Sodium standard blackbody radiation sources are systematically measured, such as temperature uniformity of the three-zone furnace, temperature stability of the blackbody, axial temperature uniformity of the blackbody cavity, temperature uniformity of the blackbody cavity aperture, temperature uniformity of the heat pipe thermometer well and so on.2) The performance of blackbody radiation source is evaluated; axial temperature uniformity of the blackbody cavity effects on the blackbody cavity emissivity is discussed; the uncertainty factor of blackbody radiation source is analysed; each uncertainty components are described; the expanded uncertainty of each blackbody sources are listed. The uncertainty of the Cesium heat pipe is0.09℃and0.1℃at300℃and550℃. The uncertainty of the Sodium heat pipe is0.12℃and0.13℃at550℃and950℃.3) The multi-wavelength radiation thermometers (LP4, RTA-9032, Hertronics KT19, TRT4.82) are used to measure the radiance temperature of standard blackbodys and customer’s blackbodies, and compare the value of radiance temperature, and research the multi-wavelength radiance temperature calibration method, analyse the spectral emissivity of customer’s blackbodies.4) The lens free radiation thermometer is calibrated by the standard blackbodies and the performance of the lens free radiation thermometer is researched.