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1 June 1992 Wafer tube for conversion and intensification of thermal images
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Among various devices intended for radiant flux imaging, those involving direct conversion are most space-saving and cheap. The major difficulty in their implementation is selection of the recording medium and the physical principle of data read-out from this medium. We have developed and tested a wafer tube for direct conversion of thermal images into visible ones using ferroelectric LiTaO3 as the recording medium and employing for read-out purposes the effect of exoelectron emission that accompanies alterations of a ferroelectric polarization. The design and operation principle of a vacuum tube are as follows. Thermal radiation passing through the tube''s germanium input window is focused onto an absorbing coating and transformed into a thermal field which in turn is transformed pyroelectrically into polarized charges distributed over a LiTaO3 target surface facing a MCP. Owing to a vacuum gap between the target and the MCP, the distributed pyroelectric charges are transformed into an electric field that sets over the target surface. Under the action of exoelectron emission the resulting pyroelectric field turns into an electron flux directed toward the MCP input surface. The emission flux amplified by a chevron-type MCP produces an image on a phosphor screen. The earliest manufactured tube enabled resolution of up to 3 p.l./mm for (lambda) equals 10 micrometers .
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Boris Efimovich Dashevsky, Alexander L. Surovegin, and Vladimir I. Pechorsky "Wafer tube for conversion and intensification of thermal images", Proc. SPIE 1655, Electron Tubes and Image Intensifiers, (1 June 1992);

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