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Vapor-deposited CaWO4 phosphor

Published online by Cambridge University Press:  31 January 2011

P. F. Carcia ,
M. Reilly ,
C. C. Torardi ,
M. K. Crawford ,
C. R. Miao  and
B. D. Jones
P. F. Carcia
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
M. Reilly
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
C. C. Torardi
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
M. K. Crawford
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
C. R. Miao
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
B. D. Jones
Affiliation:
DuPont Central Research and Development, Experimental Station, P.O. Box 80356, Wilmington, Delaware 19880-0356
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Abstract

In this paper we describe the preparation, microstructure, and x-ray excited luminescence of vapor-deposited CaWO4 films up to about 50 μm thick, comparing them to particulate CaWO4 phosphor screens, used in medical diagnostic imaging. Films that we e-beam evaporated on substrates heated at or above 500 °C were polycrystalline with the scheelite structure, while on unheated substrates, films were initially amorphous but became crystalline after annealing them in air above about 750 °C. Crystalline CaWO4 films irradiated with x-rays produced light emission peaked at 430 nm. The emission intensity depended on film thickness and grain size and was comparable to particulate CaWO4 phosphor screens. Because the vapor-deposited films also exhibited superior resolution, they are promising for diagnostic x-ray imaging.

Type
Articles
Information
Journal of Materials Research , Volume 12 , Issue 5 , May 1997 , pp. 1385 - 1390
Copyright
Copyright © Materials Research Society 1997

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