General Electric Company

Robert K Swank

Dominic A Cusano

Philip J White

Stanley Joseph Lubowski

Kei-Hsiung Yang

Scintillator structures are disclosed in which the phosphor is embedded or suspended in an optically transparent matrix which is selected or adjusted to have an index of refraction which is approximately equal to that of the phosphor embedded therein at the wavelength of the light emitted by the phosphor. In accordance with one embodiment of the invention, BaFCl:Eu is embedded in a matrix formed by the polymerization of 2-vinyl napthalene and vinyl toluene. The scintillator structures of the present invention provide superior optical coupling to photoelectrically responsive devices. Also disclosed are methods for manufacturing index-matched phosphor scintillator structures.

Index-matched phosphor scintillator structures

An improved direct charge readout electron radiography apparatus of the type having an upper electrode receiving differentially-absorbed X-radiation, a lower electrode including a plurality of parallel transparent, conductive strips overlaid with a layer of photoconductive material; and means for scanning a beam of light through the transparent strips and into the overlying photoconductive material layer for selectively transferring charge patterns induced therein responsive to the pattern of differentially-absorbed X-radiation, utilizes at least one lead means strip, positioned substantially transverse to, and spaced from the ends of, the plurality of conductive strips. The transverse lead means strip is connected to sequential ones of the parallel strips responsive to illumination of the photoconductive material in the area between the transverse strip and an adjacent end of each sequential parallel strip. The reduction in device capacitance in parallel with a device output signal, facilitates an increase of about 100 times in the amount of readable charge, for equal exposures. Apparatus for optically scanning each conductive strip; while maintaining the connection thereof to the transverse lead means, is also disclosed.

Direct charge readout electron radiography apparatus with improved

A phosphor screen for converting x-rays to light includes a large number of discrete columns of the phosphor material, say doped CsI, with the spaces therebetween preferably filled with a reflective substance, which itself may be phosphor (e.g., Gd.sub.2 O.sub.2 S or La.sub.2 O.sub.2 S). Because of the resulting inhibition of lateral spread of light within the phosphor screen, it may be made thicker than conventional screens while achieving at least as high resolution and contrast, thereby increasing brightness (and thus requiring lower x-ray 'doses'). A method for making the screen includes using a patterned substrate and wide-angle vapor deposition (as in a hot-wall evaporator) so as to deposit the phosphor only on the raised portions of the substrate.

Process of making structured x-ray phosphor screen

A conventional x-ray screen-film system includes a phosphor intensifying screen 'sandwich', including a backing layer facing the x-rays, the phosphor layer itself, and a so-called 'overlayer' adjacent the photographic film. X-rays passing through the backing cause scintillations within the phosphor, emitting light photons which, in turn, pass through the overlayer, a small air gap (caused by lack of perfect optical contact of the overlayer and the adjacent surface of the film) and into the film so as to form a latent image on the photographic film. The present change involves making the overlayer partially light absorbing so that those light photons which, for example, have been totally internally reflected at the overlayer to air gap surface, returned into the phosphor and then scattered out again through the overlayer, will be absorbed to a much larger extent than those light photons which travel more or less directly from their point of origin through the overlayer into the film, since the indirectly transmitted photons will travel through the overlayer at least three half-trips (at least two of which will be at a substantial angle and therefore through a relatively long path). This selective absorption of the long-path light photons substantially increases the resolution of the screen-film system without adversely affecting the signal-to-noise ratio (in particular, the quantum mottle).

Radiographic screen with improved resolution

A phosphor screen for converting x-rays to light includes a large number of discrete columns of the phosphor material, say doped CsI, with the spaces therebetween preferably filled with a reflective substance, which itself may be a phosphor (e.g., Gd.sub.2 O.sub. 2 S or La.sub.2 O.sub. 2 S). Because of the resulting inhibition of lateral spread of light within the phosphor screen, it may be made thicker than conventional screens while achieving at least as high resolution and contrast, thereby increasing brightness (and thus requiring lower x-ray 'doses'). A method for making the screen includes using a patterned substrate and wide-angle vapor deposition (as in a hot-wall evaporator) so as to deposit the phosphor only on the raised portions of the substrate.

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Schenectady, NY, United States of America

Robert K Swank