AN ABSOLUTE THERMAL RADIATION CALORIMETER

To allow the absolute calibration of field and laboratory radiometers in the range 0.1 to 1.5 cal/cm(2) sec, a continuous flow radiation calorimeter has been constructed, based on a design originally developed by the British Joint Fire Research Organization. The temperature difference established between a water outlet and an inlet is sensed by a thermistor bridge and the radiation intensity measurement is made in terms of the level of the electrical power, applied to a built-in immersion heater, which is necessary to reproduce the same temperature difference.
Reprinted from: Canadian Journal of Physics, v. 39, no. 11, November 1961, p. 1583-1594. ISSN: 0008-4204