INFRARED RADIOMETER FOR RADIATION AND TEMPERATURE MEASUREMENTS OF REMOTE OBJECTS

Abstract

The amount of radiation emitted by any object depends on its emissivity and the fourth power of its absolute temperature. For temperatures from $0^{\circ}$ to $500^{\circ} C$, the radiation emitted falls in the infrared range from 1 to 15 microns. A radiometer will be described which permits measurements of the absolute radiation level of remote objects by continuously comparing their infrared radiation to an internal black body reference standard. The radiometer uses two thermistor infrared detectors. One of the detectors is equipped with a KRS-5 window which transmits from 6 to 30 microns; the other is equipped with a filter slide permitting examination of selected portions of the spectrum. The field of view of the instrument is determined by the size of the thermistor infrared detector. Rectangular fields of view ranging from $0.1^{\circ}$ to $0.5^{\circ}$ can be provided. The calibration of the instrument will be described, and calibration data for various sizes of field of view will be given. The application of the instrument to various temperature measurement problems will be discussed, including a complete description of recent measurements of a continuous industrial process.