Abstract
Laboratory and space research have both benefited from the new spectrally selective ultraviolet photodetectors. Large band-gap photoemitters, such as cesium telluride, having high quantum efficiencies in the ultraviolet and very low yields at longer wavelengths are now available. An image tube with such a cathode combines the advantages of spectrally selective photoemission with the flux-integrating property of photographic emulsion. Observations can thus be made at selected ultraviolet wavelength regions, either photographically or visually, even in the presence of strong long wavelength backgrounds. Visual measurements with a Cs-Te image converter, having a sapphire faceplate and a green phosphor, were made with the following results: (a) cathode quantum efficiency is 0.016, which is expected to improve in future tubes; (b) minimal detectable converted 2537 A irradiance is 4×10-5 ergs cm-2 sec-1; and (c) tube background is undetectable. Mercury spectra obtained with this tube demonstrate the expected high rejection of visible light. Tables are included which list the brightnesses of several extended ultraviolet and visible sources of interest in the space sciences. The luminance of visible sources; the radiance of ultraviolet sources; and the relative brightness, on a photon basis, of spectrally converted ultraviolet sources along with visible sources are tabulated.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
