Dunkelman Lawrence. Ultraviolet photodetectors

Washington: NASA, 1963. — 16 p. Ultraviolet photodetectors - photoionization chambers, phototubes and photomultipliers.The need for detectors in spectroscopic research in both the laboratory and in space has led in recent years to the development of a variety of spectrally selective detectors which may be put into three broad categories: photoionization chambers having relatively narrow passbands within the region from 1050 A to approximately 1500 A; multiplier phototubes having high-work-function photocathodes and ultraviolet transmitting windows; and multiplier phototubes having high-work-function cathodes and no windows. This report reviews the characteristics of vacuum ultraviolet ion сhambers having fill gases such as nitric oxide, acetone, carbon disulfide, or ethylene oxide with windows of lithium fluoride, cadmium fluoride, or barium fluoride. Their quantum efficiencies range from approximately 0.10 to 0.50 photo- electron/quantum, and the chambers may be operated in a gas multiplication mode with gains of 10^ at 600 to 800 volts. The characteristics of photomultipliers and phototubes having alkali-tellurium, copper-iodine, or other cathodes with lithium fluoride, sapphire, quartz, or no windows are described. Some of the photomultipliers studied have quantum efficiencies as high as 0.20 photoelectron/quantum and exhibit long-wavelength rejection ratios of many orders of magnitude over only several hundred angstroms.