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Research paper : Improving the reliability of temperature measurements taken with clinical infrared ear thermometers (J. Ishii)−55−Synthesiology - English edition Vol.1 No.1 (2008) results of this international comparison, it was confirmed that radiance temperature scale realized on each national standard agreed well within the uncertainty level claimed by each institute (about 0.03 °C). The result of this international comparison measurement was the first report in the world for standard BBRs for clinical infrared thermometers, and it became a model case for later international comparative measurements in this field. In the Asia-Pacific region, AIST has also conducted a similar international comparison with National Measurement Institute of Australia (NMIA) and obtained satisfactory measurement results.8 Summary of research resultsAIST conducted research and development as the national metrology institute to improve reliability of new clinical infrared ear thermometers, and obtained the following results.– Developed national standard (standard blackbody radiator) with high precision (uncertainty level 0.03 °C)– Designed and established new traceability system for radiance temperature for calibration of working standard BBR. Uncertainty level of calibration achieved was 0.06 °C.– Verified international equivalence of national standard by conducting international comparison measurement with foreign national metrology institutions. Also, maintained quality of calibration service in accordance with ISO 17025 with third party approval.These results are applied to measurement management system for maintaining reliability (uncertainty level 0.07 °C) required for calibration and assessment of clinical thermometers, while providing autonomous activity for standard equipment of thermometer manufacturers. They contribute to the improvement of reliability of temperature readings of ear thermometers in the Japanese market.9 International cooperation to prevent spread of SARSDevelopment of standard blackbody radiator and calibration technologies for ear thermometer by AIST was an advanced effort in the world at the time, and the technical achievements are highly evaluated by other countries. In 2003, severe acute respiratory syndrome (SARS) occurred in the Asian region and developed into international crisis. With request of national metrology institutions of Singapore and Taiwan, the standard BBRs and technology developed by AIST were provided swiftly, and enabled to make calibration and assessment of clinical infrared thermometers for screening patients with fevers at airports and seaports. This activity was highly appreciated as a case of international research cooperation of measurement standard technology in a serious social problem that threatens safety and security[3].10 ConclusionThe efforts to establish traceability system and to disseminate standard technology for new ear thermometer were described. Development and dissemination of new measurement standard were conducted to make ear thermometers more reliable to users and to strengthen international competitiveness of Japanese manufacturers for clinical infrared thermometer that has totally a different measurement principle from conventional types of clinical thermometers. AIST developed the world’s highest quality national standard based on advanced radiation temperature standard and infrared measurement technology that had been accumulated at AIST, and built new traceability system so high quality standard can be used widely by industry and users. These results contributed greatly to improve reliability of body temperature measurement through calibration service and standardization process by AIST.AcknowledgementThe author is grateful for the support and cooperation by Tomoko Fukuzaki of National Institute of Metrology, as well as many persons in and outside AIST concerned in developing this research.TerminologyFig. 8 Result of international comparison of national standard BBR in body temperature region〇AIST △NPL UK □PTB GermanyRadiance temperatures difference of BBUs of each institute from mean value / ℃37.0 ℃41.5 ℃35.5 ℃-0.05-0.01-0.02-0.03-0.0400.010.040.030.020.05Preset value of blackbody temperature / ℃Term 1.Term 2.Radiance : Amount of radiation energy emitted in specific direction by unit time, unit area, and unit solid angle, for light emission from light source. Unit [W·sr-1·m-2].Planck’s law of radiation: Law of physics governing the thermal radiation characteristic (relationship of temperature and spectral radiation energy distribution) of ideal blackbody. It was formulated by Planck in 1900. Since emissivity is less than 1 in

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