Abstract

We have built an imaging radiometer for mapping temperature variations on the face of solar receivers. It is designed to image a 700-sun, 600-mm square solar receiver that operates between 400°C and 900°C. The imager is located 5 m from the receiver; this allows it to operate in a moderately absorbing spectral band near 1.9 μm. Over the 5-m path, the in-band transmission is about 80%, while the whole atmosphere absorbs nearly all of the sunlight; thus, the system is nearly solar-blind. We are using a 512 × 512 pixel, PbO–PbS vidicon that has a calculated signal-to-noise ratio of S/N = 9 for a 400°C receiver temperature. For temperatures over 500°C, the camera limits us to S / N = 100. The spatial resolution of the camera lens is good enough to fully resolve the temperature in each pixel. The camera mates to standard video equipment. All of the commonly used imaging radiometers either have much poorer resolution or are not solar-blind.

© 1992 Optical Society of America