ME30 - Blackbody Calibration Source
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Infrarot Messtechnik Blackbody Calibration Source for Calibration of Radiation Thermometers and Thermal Imaging Systems Temperature Range from -20 °C to 350 °C 1 ■ Aperture: 0 60 mm (2.36") ■ Cavity length: 300 mm (11.8") ■ Uncertainty: 0.15 °C ... 0.70 °C ■ Portable, weight: approx. 20 kg (44 lb) ■ Cavity source immersed in a liquid bath ■ Liquid volume: 1.35 litres (0.4 gal) ■ Excellent temperature uniformity ■ Precision controller, including a programmer ■ High stability, low controller oscillations ■ Fast heat-up: approx. 1 h for stabilization ■ Nitrogen rinsing to suppress dew point ■ Traceable by RTD-Pt100 (DAkkS calibrated) or ■ Traceable by HEITRONICS Transfer Radiation According to the latest development in technology a Blackbody Calibration Source has to be used to calibrate infrared radiation thermometers and thermal imaging systems with temperature ranges within -20 °C to 350 °C. An ideal blackbody sends out radiation -in a defined wavelength region - which only depends on its temperature. Its emissivity is 1 (Planck's law of radiation). A surface which comes very close to this perfect radiator is achieved by the aperture of a cavity whose inner surface is blackened and at a uniform temperature. When the opening is small with regard to the dimensions of the cavity, blackbody behavior is approximated. The emissivity is towards 1. This condition is achieved by a cylinder (tube with a bottom) when the ratio length to diameter is high. Therefore the opening of the cylinder is excellently suited as a calibration source for infrared radiation thermometers and thermal imaging systems. Calibration For calibration, the radiation thermometer, respectively the thermal imaging system, is placed at a certain distance in front of the blackbody's aperture and the output signal is compared to the radiation temperature Trad of the black-body. Its radiation temperature Trad can be measured by a precise HEITRONICS Transfer Radiation Thermometer (TRT) which must have the same spectral response as the radiation thermometer to be tested. Also it can be calculated by an external precise resistance thermometer RTD-Pt100 and a precise meter. History In consideration of the increasingly demanding requirements for a reliable and accurate calibration source for the

Blackbody Radiation Source ME30 The ME30 covers the whole temperature range from –20 °C to 350 °C with only two different bath liquids: a special silicone oil for temperatures from 90 °C to 350 °C and another one for temperatures from -20 °C to 180 °C. Below 40 °C an external chiller is required. In a schematic draft (Figure 1) the blackbody ME30 is illustrated. The cavity consists of a brass tube, with a diameter and clear aperture of 60 mm. The total length measures 300 mm. The back end is sealed by a 30° backplane. The inner surface is coated with a heat resident Figure 1: ME30 Blackbody...

kept at a relatively low temperature, the Controlling of bath temperature is sta- and III. Using blackbody ME30, calibration hot bath fluid does not directly contact ble only 15 °C above ambient tempe- rature (approx. 40 °C). Therefore, an external chiller must be used for lower The determination of the bath tempe- temperatures. A cooling tube is placed rature Tprobe is possible at one copper within the bath. To suppress building of tube with an inner diameter of 6 mm. ice or dew point the cavity can be rinsed Contact thermometers can be used to It is tightly soldered to the outer surface...

Temperature non-uniformity AT at a cavity depth of 200 ... 300 mm -20 °C to 100 °C: AT < 0.1 °C; 100 °C to 200 °C: AT < 0.3 °C; 200 °C to 350 °C: AT < 0.5 °C Temperature non-uniformity AT at a cavity depth of 30 ... 300 mm -20 °C to 100 °C: AT < 0.1 °C; 100 °C to 200 °C: AT < 0.5 °C; 200 °C to 350 °C: AT < 0.8 °C Standard uncertainty u of the radiation temperature at a cavity depth of 200 mm to 300 mm Calibration with RTD Pt100 calibrated by a certified laboratory (in Germany: DAkkS) -20 °C to 100 °C: u < 0.23 °C; 100 °C to 200 °C: u < 0.36 °C; 200 °C to 350 °C: u < 0.54 °C Standard...