Lead Selenide Cells for Infra-Red Spectroscopy

Abstract

The advantages of lead sulphide cells¹ as detectors in infra-red spectrometers have already been described² for the region between 1 and 3 µ. Although it appears that the useful range of these cells may be extended slightly by working at liquid air and liquid hydrogen temperatures³, it seemed to us more profitable to explore further the possibilities of lead selenide cells as a means of extending the range of photoconductive methods in the infra-red. Reports of war-time work in Germany indicated that lead selenide had a peak sensitivity near 3·4 µ as compared with the lead sulphide peak near 2·6 µ; but no figures have been available on the actual performance of these German cells, relative to some standard such as a good vacuum thermocouple. The fact that lead selenide cells never got beyond the laboratory stage in Germany would seem to indicate that progress there had not reached the stage where the lead selenide cell was superior to the thermocouple or bolometer.