This artifact is part of a set of infrared detectors that typify those that were used by astronomers from the 1940's into the 1960's. This unit is a commercial Ektron lead sulfide (PbS) detector made by Kodak. The operation of these tubes depends on the change of electrical properties of PbS when exposed to infrared radiation. The change in conductivity caused by impinging photons is a direct measure of the intensity of the infrared radiation when amplified by appropriate electronic circuits. Ektron PbS tubes such as this one were used as detectors for an infrared spectrometer installed in 1961 on the 82 inch McDonald telescope at the University of Arizona. This instrument was used by the astronomers Robert Cashman and Gerard Kuiper for detailed studies of stellar spectra. This tube is one from a set retained for actual use because of its good signal to noise ratio. The set of detectors was donated to NASM in 1994 by Dale P. Cruikshank.
