Miniature Net Radiometer Improvements

Abstract

An improved net radiometer was designed with increased sensitivity to match a ±5-mv potentiometer used in a multipoint recording system. Its sensitivity is sufficient to give a full-scale range of ±1.4 ly min?1, with a recording sensitivity and accuracy of 0.003 ly min?1. The radiometer sensor consists of a 22-junction manganin-constantan thermopile with compensating thermistor embedded in epoxy resin. Effects of ambient temperature from 11 to 54C are virtually eliminated by means of a circuit comprised of a shunt thermistor and micronminiature rheostat. The blackened surfaces of the transducer are shielded against the effects of wind by thin polyethylene hemispheres. The improvement also include uniform sensitivity among sensors, better spectral response, and relative ~ of construction.