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Precision Infared Radiometer

Model PIR

The Precision Infrared Radiometer, Pyrgeometer, is intended for unidirectional operation in the measurement, separately, of downwelling or upwelling longwave irradiance. Unlike instruments that measure the shortwave (short) irradiance, there is no official ISO/WMO classification of pyrgeometers which are designed to measure the longwave (infrared) irradiance from the sky. The PIR comprises the same wirewound thermopile detector and temperature compensation circuitry as found in the SPP pyranometers. This thermopile detector is used to measure the “net radiation” of the PIR and a case thermistor (YSI 44031) is used to determine the outgoing radiation from the case. A dome thermistor is also included if one wishes to measure the dome temperature as compared to the case temperature to make any “corrections” to the final result.

CLICK HERE to download Specifications [PDF]

Field of View 180° (2π sr)
Spectral Range approx, 4-50 microns
Sensitivity approx. 3 μV / Wm-2
95% Response Time 5 Seconds
Temperature Response 0.5% (-30°C to +50°C)
Linearity 0.5%
Stability 1% per year
Zero Offset 2 Wm-2
Tilt Response 0.5%
Uncertainty 5 Wm-2
Operating Temperature
Range -50° to +80°C
Operating Humidity
Range 0 to 100% RH
Traceability World Infrared Standard Group (WISG) International Practical Temperature Scale (IPTS)
Application Working Standard or Network Mesurements