TY - JOUR N2 - Determining the size of source effect of a radiation thermometer is not an easy task and manufacturers of these thermometers usually do not indicate the deviation to the measured temperature due to this effect. It is one of the main uncertainty components when measuring with a radiation thermometer and it may lead to erroneous estimation of the actual temperature of the measured target. We present an empiric model to estimate the magnitude of deviation of the measured temperature with a long-wavelength infrared radiation thermometer due to the size of source effect. The deviation is calculated as a function of the field of view of the thermometer and the diameter of the radiating source. For thermometers whose field of view size at 90% power is approximately equal to the diameter of the radiating source, it was found that this effect may lead to deviations of the measured temperature of up to 6% at 200ºC and up to 14% at 500ºC. Calculations of the temperature deviation with the proposed model are performed as a function of temperature and as a function of the first order component of electrical signal. L1 - http://www.journals.pan.pl/Content/106355/PDF/10.1515mms-2016-0050%20paper%2015.pdf L2 - http://www.journals.pan.pl/Content/106355 PY - 2016 IS - No 4 EP - 667 DO - 10.1515/mms-2016-0050 KW - size of source effect KW - radiation thermometer KW - temperature KW - field of view A1 - Cywiak, David A1 - Cárdenas-García, Daniel A1 - Rodriguez-Arteaga, Hugo PB - Polish Academy of Sciences Committee on Metrology and Scientific Instrumentation VL - vol. 23 DA - 2016.12.15 T1 - Influence of Size of Source Effect on Accuracy of LWIR Radiation Thermometers SP - 661 UR - http://www.journals.pan.pl/dlibra/publication/edition/106355 T2 - Metrology and Measurement Systems ER -