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Photomultiplier window materials under electron irradiation - Fluorescence and phosphorescenceThe fluorescence and phosphorescence of photomultiplier window materials under electron irradiation have been investigated using a Sr-90/Y-90 beta emitter as the electron source. Spectral emission curves of UV-grade, optical-grade, and electron-irradiated samples of MgF2 and LiF, and of CaF2, BaF2, sapphire, fused silica, and UV-transmitting glasses were obtained over the 200-650-nm spectral range. Fluorescence yields were determined on these materials utilizing photomultiplier tubes with cesium telluride, bialkali, and trialkali (S-20) photocathodes, respectively. Optical-grade MgF2 and LiF, as well as electron-irradiated UV-grade samples of these two materials, show enhanced fluorescence due to color-center formation and associated emission bands in the blue and red wavelength regions. Large variations in fluorescence intensities were found in UV-grade sapphire samples of different origins, particularly in the red end of the spectrum, presumably due to various amounts of chromium-ion content. Phosphorescence decay with time is best described by a sum of exponential terms, with time constants ranging from a few minutes to several days.
Document ID
19750059286
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Viehmann, W.
Eubanks, A. G.
Pieper, G. F.
Bredekamp, J. H.
(NASA Goddard Space Flight Center Greenbelt, Md., United States)
Date Acquired
August 8, 2013
Publication Date
September 1, 1975
Publication Information
Publication: Applied Optics
Volume: 14
Subject Category
Optics
Accession Number
75A43358
Distribution Limits
Public
Copyright
Other

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